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Duct Tape for Pest Control

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At the Plant-a-Row-for-the-Hungry garden where I volunteer, squash bug eggs have shown up on some of the squash plants. The eggs stick very tightly to the leaves, making them difficult to remove by hand. Duct tape, though, can help with egg removal.

Why are squash bugs “bad”?

Squash bugs aren’t essentially bad, but their activity on our plants can have a bad result. North Carolina State University’s Extension tells us that squash bugs suck the sap out of our squash plants.

Even if the plants don’t die directly as a result of this feeding activity, it can weaken them. The result is that they can make fewer squashes and become wilted. Neither of those outcomes is good. Getting rid of the eggs can slow the infestation down.

How to use tape to remove squash bug eggs from leaves

Cluster of tiny, shiny, bronze colored eggs on a green leaf.
Cluster of shiny, bronze colored squash bug eggs on a squash leaf.

First, identify the clusters of eggs.

What the eggs look like

Squash bug eggs are pretty distinctive. They are shiny, hard, bronze-colored, and appear in clusters on the leaves of squash plants. Sometimes, they are on the stems, too, but this is less common.

Why remove the eggs, rather than smash them where they are? These particular insect eggs are difficult to smash without damaging the leaves. Removing the eggs completely from the plant is the best hope for keeping the numbers of hatching eggs to a minimum.

Duct tape egg removal technique

Actually, the blue painters tape works, too, if you don’t have duct tape. It is likely that clear package-sealing tape would also work, but I haven’t tried it.

Bronze-colored bug eggs and hairy yellow larvae stuck to the sticky side of a piece of duct tape.
Duct tape can lift eggs and squishy larvae from leaves of your garden crops.

Just press the sticky side of a short section of tape to the squash bug eggs, then peel it away from the leaf. Most of the eggs will be stuck to the tape.

You may need to press a fresh section of the tape to the eggs a second time to get them all, but the tape works. With little effort on your part, the eggs will be gone from the leaves.

Now, of course, those shiny eggs are on the tape. When your piece of tape is “full”, fold it over and smash the eggs as well as you can, before putting the tape into a trash bin.

Duct tape can lift away other pests, too

You may have noticed that there are some yellow fuzzy things on the tape pictured above, along with the squash bug eggs. Those fuzzy things are the larvae (babies) of squash beetles.

Normally, I just smash those beetle larvae with my fingers, but I already had the tape in hand. Picking the larvae up with the tape was convenient, easy, and less icky than my usual method.

You can read about squash beetles and the damage they can inflict on your squash patch in my 2018 article about those particular pests. Older articles, from 2015 and 2012 confirm that this is not a new pest for my area.

Upbeat pictures, to end a “pest post”

After thinking about pests for awhile, it is good to switch over to thinking about more of the positive parts of gardening and being out of doors. These pictures might help:

  • Yellow swallowtail butterfly resting on a large yellow squash flower; several bees are clustered in the center of the large flowers
    Yellow swallowtail butterfly on large squash flower, that also has several bees working at the center.
  • Tomatoes, squash, cucumbers in a cardboard box.
    Home garden vegetables from a recent morning’s harvest.
  • Frog on the table on our back deck.
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The Mid-July Garden

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From gardens across the area, I’ve had reports of great successes and annoying troubles. Gardeners are bringing amazing vegetables into their kitchens from some of their crops, but the usual troubles of mid-summer are beginning to appear.

First — here are some successes:

  • A recent morning’s harvest
  • ‘Park’s Whopper’
  • ‘Blue marbut’ pole bean flowers
  • ‘Oda purple bell’ peppers
  • My Southern pea patch
  • ‘Mrihani’ basil, a new variety for me

Now for some less-than-successes, which we all experience to some degree pretty much every year:

Insect pests

In the past week, I’ve seen for myself or heard other gardeners discuss these garden pests:

green tomato with hole near stem
Hole in tomato near the stem is a sign of fruitworm activity
  • Fruit worms on tomatoes and peppers (in my own garden)
  • Pickleworms on squash, melons, and cucumbers
  • Squash vine borers on yellow squashes and zucchini

Plant disease

More than one gardener has mentioned that all their tomato plants, except for one, look healthy. The one exception has been a plant that wilts in the day, then seems to recover at night.

Going through the steps to identify the cause, listed in my “wilting tomato plants” article, can help. Checking soil moisture and looking for stem damage are easy steps that anyone can do. The hard steps are the ones that ask the gardener to sacrifice the plant.

I understand. We love plants. Pulling them up to look at the roots or cutting them down to look inside the stem just seems wrong. However, those are the best ways to identify the problems that begin underground (nematodes and wilt-funguses). Also, leaving ailing plants in the garden can allow some problems to spread to other plants.

Problems caused by factors like the weather

red tomato showing a black soft spot on its underside
Blossom end rot appears on the bottom side of a tomato

Another way to name these problems is to call them “physiological”. They are the plant’s reaction to things like temperature and uneven watering (or too much rain, then no rain, then too much rain, repeat).

Blossom end rot

I see this most often in tomatoes, but Iowa State University’s article on blossom end rot says it also occurs in peppers and squashes. This looks like a dark soft spot that appears at the bottom of the fruit — the side opposite the stem — and Iowa State’s article says it is caused by a lack of calcium, that is caused by uneven watering.

Considering that I was away from home for much of May and June, it may be a miracle that I have seen blossom end rot on only a few of my tomatoes this year. Or, maybe the miracle is in the mulch that I put down before our travels began. Mulch keeps moisture in the soil longer.

Other gardeners have been less lucky; a large number of their tomatoes have this problem.

Sunscald

If there are squishy spots on the shoulders, up near the stem, of your blocky fruits like tomatoes and bell peppers, the cause is likely to be exposure to too much sun. In essence, the fruits get sunburned, but the specialists call it sunscald.

Avoiding sunscald is a good reason to prune tomato and pepper plants as little as necessary. (To see how I prune my tomato plants, watch the video in my article on determinate vs. indeterminate tomatoes.)

Some plants, even without pruning, do not have enough — or large enough — leaves to shade their fruits. This could mean that the plants are not getting enough nutrients to grow well.

Tomatoes not getting ripe

A lack of tomato-ripening is causing frustration among several gardeners I spoke with last week. There are plenty of big, green tomatoes on their plants, but none are turning red, even though they should be.

Depending on which state’s publications you read, in order for the red pigment in tomatoes to form, the daytime temperature has to stay either below 86 degrees F (Ohio State University) or below 90 degrees F (Arizona State University). The difference may be in the tomato varieties tested.

Nighttime temperatures also need to go below 70-to-75 degrees F for the red pigment to form.

Weirdly enough, my tomatoes are ripening on the plants, and they are growing with essentially the same air temperatures as the tomatoes of my gardening friends.

One of my friends is growing one of my ‘Park’s Whopper’ plants, started alongside the one that is in my garden, so we know that the problem isn’t just a difference in tomato varieties. Maybe my plant is in a cooler spot — with a different enough “microclimate” to allow ripening.

If your tomatoes are not ripening, and you are sure that they should be by now, consider rigging a shade cloth over your plants. Shade cloth can reduce the temperature by 5-9 degrees F, which could be all that your tomatoes need.

Tomato plant and yellow flowers
Section of my July garden, with black-eyed Susans to the right.
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What Caused my Tomato Plant to Wilt?

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Some varieties of tomato die in my yard. The most obvious sign of their impending doom is wilting. The presence of many dead leaves is another easy-to-notice sign.

Wilted green leaves on a tomato plant.
Wilting of tomato leaves can have many causes.

When a tomato plant starts to look extra-pathetic, figuring out the cause is important. Sometimes, the plant can be saved. More often, it can’t, but knowing the cause can help the gardener prevent problems in the next-summer’s garden.

This article describes the way I figure out what is wrong with an ailing tomato plant.

Wilt versus leaf roll

Stressed plants will sometimes roll or curl their leaves. This is different from wilting. In the leaf roll response, leaves roll or curl upward at the edges. The roll can be extreme, so that each rolled leaf is almost cigar-shaped, with the lower leaf surface seen on the outside of the roll.

University of Washington’s publication on leaf roll in tomatoes explains that this sign has several possible causes, that are not diseases, including high temperatures and fluctuating soil moisture levels, and that it is more common in indeterminate plants than in determinate plants.

Wilted leaves, unlike leaves doing the leaf roll thing, do not roll inward/upward.

Wilting caused by something other than disease

Wilting in tomato plants can have non-disease causes.

Soil moisture

The obvious first thing to check when a plant looks wilted is the soil moisture level.

Tomato plant standing in water puddle
Too much water.

It makes sense to pretty much everyone that a plant might wilt in dry soil, but when soil is too wet, that can also cause wilting due to roots that have drowned and no longer work to pull water into the plant.

If you aren’t sure about the soil moisture level, poke a trowel down into the soil not too far from the wilted plant, then pull back on the handle to make an open wedge that your hand will fit into. Reach down into the soil with a bare hand to check for dampness.

Too-dry soil is one cause of wilting that a gardener can fix. Too-wet soil is less easy to fix quickly, and a drowned root system takes a long time to overcome.

Damage to the main stem

If a plant is wilted, another thing to check after soil moisture is whether the main stem is damaged.

tomato stem showing wound
Plant may wilt above a wound on the stem.

If the main stem is very damaged, it is possible that the plant’s water-conducting tubes have been damaged, too, and can not move water well-enough through the plant.

A damaged tomato-stem cannot be fixed. If the damage is near the ground, caused by a mechanical injury (being bumped or scraped), raising up a mound of soil above the damaged area may help.

Tomato plants can make new roots on the main stem,. The mounded up soil can allow new roots to form above the damage. Growing new roots takes time, though. The tomato harvest may be slower to arrive and smaller than for a plant that didn’t have a delay.

Loss of roots due to gophers

Gophers can ruin a garden, plant by plant. They burrow underground and eat plant roots. Most of us will not ever have this problem in our gardens, but gophers were my second stepdad’s garden nemesis.

Gophers usually leave mounded trails through the garden. If a plant simply falls over one day, and you discover that its roots have disappeared, look for the trails.

A plant that has lost its roots to gophers won’t recover.

Wilting caused by diseases in the soil

The next step, if all of the above do not seem to be the cause of wilting in your tomato plant, is to dissect the plant for a closer look.

Cut across the main stem near the ground, and look inside the stem. Is the tissue a healthy greenish-white all the way across, or are there some brown areas inside the stem?

Fungus underground

Cross section of tomato stem showing brown sections inside the stem; evidence of a fungal wilt disease.
Cross section of tomato stem showing the browned areas that are evidence of fungal wilt disease.

The two fungal diseases that cause most of the wilting in tomato plants that I have seen in Georgia are fusarium wilt and verticillium wilt.

To be honest, I usually cannot tell which one has caused the trouble, but both will show browned areas inside the stem that are where the fungus has entered the plant through the roots and clogged up the water-conducting tubes.

These diseases cause more trouble in very wet soils.

I have grown the heirloom tomato variety ‘Mortgage Lifter’ in both wet and dry years. In dry years, the plants are productive and make delicious tomatoes through the whole season. In rainy/wet years, the plants die from one of these fungal wilt diseases by mid-July.

EDIT from 20 Aug 2019 – A new soil-borne fungus that attacks tomato plants has shown up in my garden. See my article “What Caused my Tomato Plant to Wilt, Part 2” to read about Southern Blight in my garden.

Bacterial wilt

Bacterial wilt causes rapid wilting of the whole plant. If your plant has wilted completely, seemingly overnight, this is a cause to suspect.

University of Florida’s information on bacterial wilt describes a simple stem-streaming test that you can do at home, to check for this disease:

Cut a stem from the wilted plant and suspend the cut end in clear water. White, cloudy material oozing out of the cut end into the water is a sign that the plant is infected by bacterial wilt. If nothing oozes out of the stem, then bacterial wilt is not the cause of your tomato plant’s wilting.

I have only been able to confirm bacterial wilt as a cause of tomato wilting once, in someone else’s garden, in my many years of looking at wilted tomato plants. That makes me think that this cause of wilting is not super-common.

Wilting caused by nematodes in the soil

Root-knot nematodes — microscopic wormlike creatures — are another possible cause of wilting in tomato plants. If all of the above-ground parts of the plant check out as being fine, except for the wilting, the next place to look is the root system.

Dig up the roots of the wilted plant, and examine them carefully. Healthy roots are creamy white in color, and they are fairly uniform in diameter, gradually decreasing in width as you follow them to the growing tips.

The roots of tomato plants infested by root-knot nematodes are lumpy, looking a bit like they have swallowed large beads.

The University of Arkansas publication (pdf) about root-knot nematodes includes photos of healthy and infested roots, side by side, for comparison. If your plant’s roots are lumpy, then root-knot nematodes are the likely cause of wilting.

Wilting caused by leaf diseases

All of the above causes of wilt can include some yellowing of the leaves, but not brown spots on the leaves. If a tomato plant has many wilted, yellowing and/or browned leaves, and it also has a lot of spotted leaves, then a leaf spot disease is a likely cause.

Leaf spot diseases can affect most tomato plants as the season progresses. These diseases tend to be worse in wet years than in drier years, but nearly every spring-planted tomato plant in the Southeastern US will show some signs of a leaf disease by the end of September.

  • Brown spots on tomato leaf are sign of leaf disease.
    Brown spots on tomato leaf are a sign of leaf disease
  • Tomato plant with nearly all brown leaves
    Too many dead leaves; this plant will not recover.

The brown spots on the leaves are an easy-to-see clue.

Cure for wilted tomato plants

Many of the causes listed above do not have an easy cure. Most of them, though, can be avoided in next-year’s garden with some planning.

If the garden soil is in a place that stays wet much of the time, raising it up a few inches can improve drainage and reduce the risk of the moisture-related wilt problems, like the soil-borne diseases.

Another simple step is to grow disease-resistant and nematode-resistant varieties. Many of these are hybrids, not heirlooms, but some heirloom varieties also survive just fine in my garden. Some will do fine in yours, too; however, finding them may take time.

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June in the Garden

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This year, because of some planned travel in May and June, I planted my summer crops later than usual. I didn’t want crops to mature to harvest-stage, and go to waste, while no one was at home to bring them into the kitchen.

The good news is that, while I was gone, the garden was fine. A neighbor (thank you, Heather!) did water the garden once, in the middle of that extra-hot, extra-dry stretch of weather in late May. However, mulch on the garden held the moisture well enough that the one watering was enough.

How the tomatoes fared

Me with a quite tall ‘Park’s Whopper’ tomato plant. PHOTO/JoeD

I had clipped off the first flower cluster from each of my two tomato plants, as part of my effort to delay production of ripe fruits. Both plants were small when I left, each of them tied to a stake in the center of their large tomato cages.

Now, the ‘Park’s Whopper’ (a hybrid variety) is taller than I am. Yesterday, we stacked another section of a Texas Tomato Cage on top of the first two, to provide support for the higher parts of the plant.

The entire ‘Park’s Whopper’ plant is gloriously green and healthy, and it holds many, many tomatoes.

  • Cluster of three immature, green tomatoes attached to a plant.
    The first tomatoes on the ‘Park’s Whopper’
  • Tomato beginning to ripen on the plant, with some brown leaves nearby.
    ‘Black from Tula’ tomato ripening, but notice the brown leaves.

The other tomato plant is a ‘Black from Tula’. This heirloom plant is not as tall, and some leaves have turned brown. I do not yet know why. Our first ripe tomato for the summer will come from that plant, I am sure, since one is already turning. It will probably be spectacularly delicious.

I think, though, based on the presence of several dead leaves, that the plant will not live to produce tomatoes for as long as the ‘Park’s Whopper’.

How the peppers fared

‘Purple bell’ peppers.

This year’s garden has three varieties of peppers. Plants of the two kinds of sweet peppers, ‘Feherezon’ and ‘Purple bell’, are all alive and productive. We lost one of the ‘Carlo Putini’ Italian hot pepper plants, but the other (there were two, originally) is healthy and loaded with peppers.

We have eaten some of the sweet peppers, but I am waiting for the ‘Carlo Putini’ peppers to turn red and fully ripe before bringing any in.

Some other crops

Cucumber/squash family plants

The cucumbers and zucchini were just seedlings when we left town in mid-May, but they are large and flowering now. The first fruits from both of those should be ready in the next week.

Bean family plants

The pole beans – ‘Blue Marbut’ – and the Southern peas were also just seedlings when we left town. They are all beginning to flower.

Annual and bi-annual herbs

All the basil plants are large, and some are making flowers. Yesterday, I brought in a lot of ‘Genovese’ and ‘Lettuce leaf’ basil to make the summer’s first batch of pesto. That batch is in an ice-cube tray in the freezer, to save for use in winter.

The parsley is large and healthy, and it will be added to many kinds of salads over the next several weeks. Purslane also has popped up around the garden, and some of that went into salads this weekend.

The borage and nasturtium plants have plenty of leaves, but no flowers yet.

Garlic and onions

Bulblets from a winter onion plant, sprouting leaves and roots.

Usually, the garlic is ready to harvest by now, but for some (unknown) reason most of the plants are still mostly green. Soon, though, it will be time to pull those plants.

The only onions in the garden this spring/summer are Grandpa Bill’s ‘winter onions’ (aka: ‘tree onions’, ‘walking onions’). The tiny bulbs that form in a cluster at the top of the stalk are sending out roots and shoots, to make new onions for the coming year.

To plant next

In the next few days, I will be starting some more summer crops, to go into the garden soon. There will be another tomato plant, this one a ‘Winter Keeper’, and some summer greens.

The greens will be Swiss chard, the varieties ‘Perpetual Spinach‘ and ‘Verde di Taglio’. The two look similar, but I am interested to find out whether they grow about the same and whether they work in the kitchen the same.

Another green is the amaranth variety ‘Chinese multicolor spinach‘. The new, small leaves are supposed to be good in salads, and the older, larger leaves for cooking.

Masses of yellow and orange flowers growing at the left side of the garden are for pollinators. The right side of the garden is green, with vegetable plants that have less conspicuous flowers.
Flowers to the left, veggies to the right — the upper garden bed in June.

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Organic Garden Pest Control

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As the summer progresses, more and more plant-eating pests will find our gardens. Farmers and horticulture specialists call this build-up of unwanted insects and other creepy-crawlies “pest pressure”, and, in the South, it can become spectacular.

However, organic gardeners everywhere have a wide range of non-chemical strategies available to reduce pest-problems.

Simple pest control strategies for organic gardeners

Remove pests by hand

Cluster of shiny orange squash bug eggss on a leaf of summer squash
Squash bug eggs can be lifted off squash leaves using the sticky side of duct tape.

One of the simplest ways to deal with a whole assortment of plant-eating bugs and beetles is simply picking them off the plants and smashing them (possibly while wearing really good garden gloves) or knocking them into a little tub of soapy water, where they will drown.  This strategy works for many kinds of beetles and bugs when the population of pests isn’t too large.

Mowing and weeding

Keeping the surrounding vegetation down helps reduce the number of places pests can hang out.

Water spray

Spraying sturdy plants with a hard stream of water can knock smaller, soft-bodied insects like aphids off a plant. Very small insects can’t always manage to climb back up. 

Barriers

Bird netting over strawberry plants
Netting set out over young plants  can protect strawberries from birds and chipmunks.

Placing fine mesh netting or a specially manufactured row cover over plants can keep them from being attacked by some kinds of insects. Especially if you want to keep an adult form from laying eggs that hatch into a destructive larva/caterpillar, this is a great strategy. I use netting over cabbage family plants to keep from getting cabbage worms and loopers on my crops. 

Netting can also protect plants from birds and small mammals, if it is placed over-and-around the plants before the birds and mammals find your crop I get to eat a lot more of my own garden-strawberries when my plants are defended from chipmunks (my nemesis…) with heavy netting.

Baits

Organic-approved baits are available for some pests, like slugs, snails, and roly-polies (aka: sow bugs, pill bugs). These work, but patience may be required.

Bacillus thuringiensis (Bt)

This bacterial product is toxic to certain insects and is certified for use in organic gardens. The one I’ve used is the brand Thuricide, and it is for managing caterpillars. This includes those Cabbageworms and loopers, tomato fruit worms and hornworms, and cucumber pickleworms. It should also include Squash Vine Borers, but the success I’ve seen with these is patchy. For the vine borers, I have had better success when using several strategies together, rather than relying on just one (see link in “change the crop” section below). 

Less simple pest control strategies

This next set of strategies includes practices that require either more thought or time or that require more than one “step” to complete.

Encourage beneficial insects (predators)

Many garden helpers, such as ladybugs, predatory wasps, and lacewings, are attracted to areas that have nectar-providing flowers nearby. Growing flowers like white clover, chives, hyssop, comfrey, or viper’s bugloss in the garden or in nearby areas can attract these helpers to your yard. Dandelions are another favorite.

The predatory insects also need a source of water, such as a very shallow birdbath that includes rocks or sand (to help them climb out, if they fall in).

Change the timing of your planting

beans and small purple bean flowers growing on a bush bean plant
A bush bean patch can make a lot of beans before beetles arrive to destroy the plants.

Mexican Bean Beetles can strip all the green tissue off bean plants pretty quickly. They aren’t a problem every single year, but some years they totally halt production of beans in the garden because they’ve actually killed the plants.

These pests don’t typically become abundant in my garden, even in a “bad” year, until July. That means that early-planted bush beans have ample time to make a great crop and then be removed from the garden completely after the gardener has harvested plenty of beans for fresh use and more to either can or freeze for later use.

If your garden has had a couple of bad Mexican bean beetle years, this strategy can be a great work-around for the problem.

A similar strategy of changing the planting dates, based on when a particular pest seems to appear, can work for other crops, too.

Change the crop

One mature, buff-colored butternut squash and one green, immature butternut squash, growing next to each other on a vine.
Butternut squash resist damage caused by squash vine borers.

Around mid-summer, gardens across the area are filled with wilted squash plants. Most of these plants are dying (or dead, with a gardener nearby holding a watering can and a hopeful expression on his or her face) from damage caused by the squash vine borer.

It turns out that we grow four main species of squash for food: Cucurbita pepo, Cucurbita mixta, Cucurbita maxima, and Cucurbita moschata. Of these, the C. pepo group contains most of the squashes we like to grow and eat: zucchini, summer squash, acorn squash, spaghetti squash, and most pumpkins. Sadly, this group is highly susceptible to squash vine borers. 

The C. moschata group has the best resistance to the borers. The most familiar representative of this group may be the butternut squash, but this group also contains the cheese squashes, ‘Seminole Pumpkin’ squash, and a variety of squash sometimes called ‘Trombocino Rampicante’ (sometimes also called ‘Zucchetta’) that, when immature, is somewhat similar to zucchini. 

Most of the C. moschata plants can grow to sprawl across 20-30 feet of garden. Gardeners working in smaller spaces can look for a dwarf version, like a dwarf butternut.

Not all insects are pests

For new gardeners, becoming comfortable with the universe of insects that inhabit the garden can take some time. It might help to remember that some of these creepy-crawlies are working with you, not against you.

Pollinators

Some insects are the pollinators that help your crops make delicious food for you to bring into the kitchen. Pollinators include many kinds of bees, butterflies, wasps, beetles, and flies.

The babies of butterflies are caterpillars, which do eat plants. This means that gardeners should determine some level of acceptable damage, not killing every caterpillar on sight, so we will have plenty of butterflies. Planting some crops specifically for caterpillars may help. 

The ones that are wimpy eaters

Some insects that eat plants never become abundant enough to keep your plants from making good food. The caterpillar called the bean leaf roller is usually one of these. These may not be “garden helpers” like some of the other creepy-crawlies, but they aren’t exactly the bad guys, either. I usually leave these alone.

Predators

Saddleback caterpillar almost covered up in the white eggs of a parasitic wasp.
Some wasps lay eggs on caterpillars; baby wasps that hatch will eat the caterpillar.

Becoming familiar with the predators (wasps, ladybugs, lacewings, and their babies) can help you avoid killing them by mistake. Of course, the predators are not all super-choosy about their prey, so some of them may eat others of your beneficial insects. Try not to worry about that too much.

The caterpillar covered with wasp eggs in the picture nearby is a saddleback caterpillar. This type of caterpillar has stinging hairs that are very unpleasant for people to encounter.

 

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When to Harvest Summer Squashes

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The summer squashes are the ones we grow to eat soon after harvest; they are not “storage squashes” like pumpkins and butternuts. For most purposes, we want to harvest the summer squashes while they still have thin skins, tender flesh, and soft seeds.

To achieve this ideal, a gardener needs to pay attention to the garden. Squashes can reach the perfect point for harvest one afternoon, then have zoomed past it by the next morning.

However, bringing good food into the kitchen is an essential part of gardening, so a little vigilance can be worth the effort.

Smaller squashes are often best

Yellow straight-neck squashes in various stages of maturity still growing on the plant.
Yellow straight-neck squashes are best when harvested small.

Some gardeners plan to eat their summer squashes raw. The veggies may be added to salads or sliced to use in scooping up dips. If “raw” is the goal, then harvesting squashes while they are small is a good practice.

As the squashes grow, they become tougher, the skins thicker, and the seeds chewier. But how can we know when the turn to toughness happens?

Some seed packets, for some varieties, provide information about when-to-harvest for the best flavor, but not all do. The guidelines below, for many kinds of summer squashes, are pulled from University Extension Service publications (from Clemson, NCSU, UGA) and from seed packets.

Yellow summer squashes, straight-neck and crookneck

Most of these will have the best quality if they are harvested before the fattest part gets more than one-and-a-half to two inches across, and while the squashes are still shiny. The first yellow squashes are usually ready for harvest about a month and a half after planting.

As the squashes mature, the skins turn dull and thick, the seeds harden, and the flesh loses its buttery tenderness. The sign that is easiest to see besides size is the loss of gloss from the skins. This doesn’t mean that larger, duller squashes are not ok to eat! However, it does mean that preparing them for use in cooking may need another step or two beyond simple slicing.

If the seeds seem tough, scoop them out before using the fleshy part in cooking. If the skin has turned weird (it happens), peel the squash before using the rest of it in your recipe. The result may not be the same as for a squash harvested at the “peak of perfection”, but it can still be good food.

If you leave larger squashes on the plant for more than a few days, the plant will slow down in making more squash. This is a good reason to check your squash plants often!

Regular Zucchini

Freshly harvested green beans and two green zucchinis in an oval basket.
Most zucchinis are best when harvested before they get more than about eight inches long.

Most varieties of zucchini should be harvested before they grow longer than about eight inches. I usually grow ‘Black Beauty‘, which gets mixed reviews from other gardeners, but it has excellent flavor, and I like the contrast of the dark-green skins with the pale inner flesh.

Round Zucchini

Round zucchinis like ‘Ronde de Nice’, ‘One Ball’, ‘Eight Ball’, or ‘Tondo di Piacenza’ should be harvested before they get any larger than a baseball. These little veggies are great for stuffing, and the smaller sizes, at two to three inches in diameter, seem to work the best for that purpose.

A reviewer on Baker Creek’s catalog website says that ‘Ronde de Nice’ survived squash vine borers and squash bugs longer than other squashes in his Arkansas garden. I haven’t tried this variety yet to find out whether the same is true in my garden in Georgia.

Scallop-edged squashes

Many scallop-type squashes, also called pattypans, should be harvested when they are between two and four inches across. However, the recommended harvest-size for ‘Scallop Early White Bush’ is much larger, at six-to-eight inches across.

This variation in recommended harvest-size is a good reason to save your seed packets, so you will have the information handy. If the seed packet is already lost, or doesn’t include the information, check your seed catalogs for best size-at-harvest for the variety, or search online.

When what a gardener really wants is a green “baseball bat”

Years ago, it never would have have occurred to me that a gardener might actually WANT an enormous, super-tough zucchini. My experience had been that we all ended up with a couple of these, even in small gardens, because zucchini plants can be huge and finding the squashes can be difficult.

Zucchini plants in a long garden bed, with corn growing at the far end.
It is easy to miss finding overgrown squashes when they are on large, bushy plants.

When I find one of these green baseball bats in my own garden, I scoop out the seeds, then grate the rest to use in zucchini bread or croquettes. However, huge zucchinis have never been my main goal. Then I met a couple of gardeners who let their zucchinis grow to hugeness on purpose.

They wanted the big, tough vegetables to make mock-apple pies. When they first explained their goal, I was skeptical, but I found several recipes online, which meant that these gardeners were not the only ones using zucchini in sweet pies.

To find out what I was missing, I used one of their big, tough zucchinis to make a pie (an example recipe is linked here) and took it to work to share with my co-workers. Everyone was amazed by the similarity to actual apple pie.

The texture of the big zucchini was a near-perfect match for the texture of cooked apples, and the cinnamon, sugar, and lemon were enough to match the flavor.

If your squash plants are not doing well

Here in the South, it is common for summer squash plants to last for only part of the summer. By mid-summer, they may have been attacked by pests and diseases that they cannot survive.

For help with problems that summer squashes can experience in the South, like squash vine borers, squash bugs, and mildew leaf diseases, see the article Summer Squash in the Southern Garden.

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When Compost is the Fertilizer

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Years ago, I somehow got the idea that a product wasn’t a fertilizer unless it had a guarantee of its N-P-K ratio (nitrogen – phosphorus – potassium) on the label.  This idea totally contradicted my personal experience of growing vegetables in mounds of nearly pure compost.

An early experience with “composted humus and manure”

Back in the early 1990s, when Joe and I first got serious about gardening in Georgia, the red clay in our yard was a major obstacle to success. I had been reading about gardening — mostly information from up North — that said: if you can grow radishes, you can grow tomatoes.

Pink radishes with leaves, on the grass next to a pair of garden shears.
Radishes are a beloved crop at my house, probably partly because we couldn’t grow them for so long!

The problem, of course, was that we couldn’t grow radishes. We added our own yard-compost to the garden, which included bags of leaves and grass clippings from our neighbors’ yards, to make more compost. However, improving the garden-soil/clay to a more loamy texture was slow.

At the time, we had small children and a tight budget. Buying enough amendments to improve the whole garden in one season was not really an option.

About the third year (could have been the fourth), I bought some commercial “composted humus and manure”, in bags, at a garden center. There was no N-P-K information on the label. The stuff was stinky, which means it was not completely composted, and it contained some large, suspicious-looking lumps (wads of cow poo?), but it was cheap.

My method was unorthodox, I am sure: I dug shallow holes, like saucers, a foot-and-a-half or more wide, in the garden, then dumped on about a half a bag of the “composted humus and manure” per hole for big plants like tomatoes and squashes, and about a third of a bag per hole for smaller plants like peppers and cucumbers. Luckily, the garden at that time was small, so not too many bags were involved.

Cluster of small tomatoes just beginning to form.
Tomato plants need more nutrients than some other crops for good production.

The holes were shallow enough that the composted stuff made low mounds. I pushed my spading fork through each mound a few times, to break up the interface between the compost and that red clay, then, I planted right into those stinky mounds.

Our plants grew, and they made plenty of vegetables. Around the middle of July, I dumped about a quarter bag of the same “composted humus and manure” around each plant as a side-dressing to provide additional nutrients, to keep that productivity going.

At the time, buying the compost meant that additional fertilizer didn’t fit in our budget. All the nutrients for plants in the garden came from the yard-compost, which was distributed throughout the whole garden, and the mounds of composted humus and manure.

What counts as fertilizer?

Greensand is a good sources of potassium for organic gardens.
Greensand is a concentrated source of potassium, with an N-P-K of around 0-1.5-5 .

The definitions of fertilizer vary, but there is general agreement that a fertilizer contains elements that improve plant growth and productivity; they are given to plants to help them grow.

I usually think of fertilizers as being products that are concentrated sources of plant nutrients. Examples are sul-po-mag for potassium or blood meal for nitrogen.  You can buy these in little bags or boxes, and a cup or two in a small garden can be enough to support good plant growth, if potassium and nitrogen are in too-low amounts in the soil.

Composts, though, are typically added by the wheelbarrow-load, instead of being measured in cups. They do not seem to be concentrated sources of nutrients.

Nutrients in compost

Information from the University of Massachusetts says that most finished composts have an N-P-K ratio of about 1-1-1.  The numbers tell the percent of that nutrient in the product, so a product that has an N-P-K of 1-1-1 contains 1% each of nitrogen, phosphorus, and potassium.

These are low amounts, considering that a standard chemical fertilizer recommended for home gardens is 10-10-10, which contains 10% each (ten times more!) of the three major nutrients.

In addition, Iowa State University’s article on the Do’s and Don’ts of Composting cautions that compost should not be considered a fertilizer, because the release of nutrients from compost is slow. Again, though, my experience was that the compost was enough.

One advantage of composts is that the nutrients N-P-K are not the only nutrients they provide. Since composts are made of broken-down plants, they also can contain magnesium, zinc, boron, iron, and other essential plant nutrients — that the original plants were made of — that support plant growth.

Is compost safe?

Safety for people

Composts made from animal manures, if they are not completely composted, can contain pathogens that are dangerous to humans, like E. coli and Listeria.  Most home-made composts will not contain manures, which lets most of us cross that off our lists of potential hazards.

However, home compost piles will contain a wide range of bacteria and fungi that can cause allergic reactions in some people. Cornell University’s Waste Management Institute recommends that susceptible individuals wear dust masks when turning the compost on dry/windy days.

Safety for the garden

Composts made with bio-solids (treated sewage sludge) can contain more heavy metals than are safe, especially when compost is used in very large amounts (from report posted on Cornell University website). Home-gardeners who are filling raised beds with purchased, all-compost mixes may want to check the origins of the compost, to see if bio-solids are in it.

Composts can also contain fairly high amounts of soluble salts (See the U. Mass article on compost use and soil fertility). This is not normally a problem in gardens and fields that receive adequate rainfall, but in greenhouses or high tunnels where the soil doesn’t get good, drenching rainfall, the salts can be a problem. Mushroom compost, especially, can be high in soluble salts (see table in Oregon State University’s pdf about organic fertilizers). 

If your garden has received many loads of compost, but productivity seems to be dropping, consider having the soluble salts level in the soil checked through your local Cooperative Extension office.

Interesting bits I learned while looking for good resources about “compost as fertilizer”

Tom Thumb lettuces in the Spring Vegetable Garden
Lettuce is a known bio-accumulator of some heavy metals.
  1. The odor/aroma of finished compost, like a damp log that is decaying in the forest, is caused by the action of actinomycetes, which are a kind of beneficial bacteria. (From a chapter summary on this webpage from ScienceDirect.)
  2. Lettuce, spinach, and celery are three crops that can accumulate heavy metals in higher amounts than other crops.  (From a Cornell University paper about compost guidelines.)
  3. In some places in the U.S., composting food scraps aboveground is not allowed. (University of Maryland article about how and why to make compost.) 
  4. Compost is known to suppress some plant diseases, but if nutrient levels are high, the ability of compost to hold down diseases is reduced. (Chapter summary from ScienceDirect.)

Why am I thinking about this now?

I have a bag of Soil3, a cubic yard of compost, that I’ve been using to amend my garden with this summer. It reminded me of the olden days, when I grew some of my crops in little mounds of compost. The good news is that the stuff in my pile of Soil3 is not at all stinky!

 

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Bridging a Garden’s Hungry Gap

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The garden can experience a little bit of a “down time” here in late May, with regard to harvests. Most of the spring crops are gone from the garden, and the summer crops are too new to produce much food. This time of lean harvests has long been known as “the hungry gap.”

Garden planted with young plants of tomato, peppers, basil will not produce food for several more weeks.
These tomato and pepper plants will not produce food for several more weeks.

In the Southern US, the spring hungry-gap is fairly brief, but in the hottest parts of the South, there can be a second time of lean harvests in August and early September, when crops fail due to extremely high temperatures that occur day and night, for weeks on end.

My gardening sister in Louisiana routinely faces this second gap in garden productivity, in August and September, that is less common in the Atlanta area.

May crops for Southern gardens

For most crops that we can harvest in May, planting in the cool weather and cool soils of early spring is required. This can take some extra effort. A few of the bridging crops will be warm-season vegetables, like bush beans and zucchini. Both of these crops could need to be protected under a frost blanket (or an old flannel sheet) if the temperature drops down below about 38 degrees F.

However, the effort of protecting the plants can be worthwhile. When I plant bush beans in early April, the plants produce mature beans that we can harvest and eat by the end of May. In 2015, our patch of Provider bush beans was producing well by May 27; other years the bush beans have come in even earlier.

In most of our gardens, though, the best bridging-crops for spring are cool season crops that can stand a bit of warmer weather. Different varieties of the same vegetable can have different tolerance to heat, so read seed information carefully to find heat tolerant varieties for late May and early June harvests.

  • Dill in the May garden.
  • Parsley in the May garden.
  • Strawberry patch in May.

This is a list of crops I’ve been able to harvest in May: strawberries, bush beans, lettuces, Swiss chard, radishes, carrots, onions, edible pod peas, English peas, beets, potatoes.

Vines of sugar snap peas, with both white flowers and peas ready to harvest.
Sugar snap peas help bridge the fresh-produce gap this year at a Plant a Row for the Hungry garden.

This year, I’ve given over a large part of the garden to a basil experiment, which means I have less room than usual for vegetables. After pulling up the truly cool-season crops, as we wait for tomatoes, peppers, cucumbers, etc, we have just strawberries, dill, and parsley. It is a very lean May/June!

Most years, by the end of June, the summer vegetables will begin to mature for use in the kitchen, but harvests in early June can, like in late May, be kind of spare.

This is a list of crops that produce for me in June: bush beans, strawberries, potatoes, onions, garlic, zucchini, peppers, Swiss chard, eggplant, assorted berries, tomatoes (cherry tomatoes usually ripen earliest).

Berries coming soon, in my yard

One major value of planting berry-type fruits in the yard is that many of them produce ripe fruits in this lower-harvest time. We’ve been eating strawberries (variety called ‘Chandler’) for a few weeks, and there are more berries ripening on those plants! For us, giving space to strawberries is easy, even though they hog the space year-round.

Other berries are on their way. The first mulberries in my yard will be ripe for harvest in just a few days, well before the last of May.

Green and red mulberries ripening on a branch of the tree will be ready for harvest when they turn black.
The earliest mulberries in my yard will be ready for harvest next week.

Raspberries, blueberries, and blackberries all will be ready for harvest in June.

  • Jewel black raspberries beginning to ripen.
  • Buds of wineberry, to ripen after Jewel raspberry.
  • Flowers of thornless blackberries. Fruits will mature later than wineberry.
  • These blueberries ripen in late June in my yard.

We can use lists of successful bridging crops to help plan next year’s planting, if harvests in May/June have been a bit light in our gardens.

Which crops fill the hungry gap in your yard?

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National Public Gardens Week

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Today is National Public Gardens Day, but next week, from 13-19 May, is National Public Gardens Week. For many of my readers, the Atlanta Botanical Garden may seem like the obvious choice of gardens to visit that week, but my nearest public garden actually is Smith Gilbert Gardens (SGG) in Kennesaw.

Years ago (2007-12) I worked in that garden, because it provided a space in those years for the Plant a Row for the Hungry (PAR) garden for which I volunteer. The PAR garden is on another property now, but SGG is still a great place to visit, especially for people whose yards are shaded by numerous tall trees and who are looking for inspiration about how to enhance those wooded areas.

Woodland plants at Smith Gilbert Gardens

Dr. Bob Gilbert, a former owner of the property, told us (volunteers in the early days) that he and his partner had planted small fruiting trees and shrubs below and around the existing trees to support the annual bird migration, especially of warblers. Each spring, when I see black-throated blues or other warblers in my backyard, I am reminded of the nearby SGG.

Leaves of bloodroot shaped like fat hands, and trillium plants that have only three leaves that attach at the top of a single stem.
Spring ephemerals, Trillium and bloodroot.

Some of the fruiting trees and shrubs planted for birds provide fruit that people can eat, too. Along the trails through the woods you can find hawthorn and the less common parsley-leaf hawthorn. A sparkleberry, with its tart but gritty fruits, is growing in the rock garden.

Growing in the shade are also many non-edible “spring ephemerals” – plants that die back in summer, but re-appear each spring.

Unusual dogwood species at SGG

Some of my favorite plants at SGG are the dogwoods.

White four-petaled flowers of Kousa dogwood on branch with dark green leaves. Petals are actually bracts.
Kousa dogwood flowers

Kousa dogwood, Cornus kousa, makes its flowers later than our native dogwood tree, Cornus florida. Kousa dogwoods resist the disease that has been killing our native dogwoods, making it a good alternative small tree for suburban yards. Even better, the fruits are edible. Like most new foods, it takes a few tries (trust me on this one) before they are a loved-fruit, but anyone looking for a “stealth fruit” for the yard might want to try this tree.

Small tree, Cornelian cherry, growing on open lawn at a woodland edge at Smith Gilbert Gardens.
Cornelian cherry at SGG.

Cornelian cherry, Cornus mas, is another unusual dogwood growing as SGG. The flowers are yellow instead of white, and the leaves tend to hang downward. This small tree is growing in full sun at SGG, but it can also grow in partial shade. Fruits of this plant are edible, and are reported to taste somewhat like tart cherries, but I have not tasted these. According to Stark Brothers nursery, two trees are needed for good pollination, to make the fruit.

Our native silky dogwood, Cornus amomum, is my other favorite dogwood at SGG. It is a shrub, not a tree. The fruits are not edible (for people), but it is great for birds, and the flowers attract many kinds of native pollinators. The specimen at SGG is along one of the woodland trails. When I saw it last week, the shrub had been heavily pruned, so it might be hard to find this year for anyone who doesn’t know where to look.

The silky dogwood in my yard is about to bloom. The flowers will be small and in clusters. When they open, the flowers will be white. The fruits, when they form, ripen to black.

Arisaema plants are Smith Gilbert Gardens, tall flowers with purple spathe and long spadix emerging.
Arisaema plants along a woodland trail at SGG.

Even if you are not super-fond of dogwoods

A visit to either SGG or your nearest botanical garden in National Public Gardens Week is a good idea. Each garden has its own mission and design aesthetic. Seeing how someone else chooses the plants and then places the plants with regard to their form, color, and other characteristics can spark ideas for our own gardens.

Smith Gilbert Gardens does not have special programs planned for National Public Gardens Week, that I know of, but check the website for hours of entry. If your nearest public garden is not SGG, consider visiting that nearer garden, instead.

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Stop Garden Weeds with Mulch

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Mulches can stop weeds from growing in the garden, or at least slow them down, making mulches a great addition to an organic garden. They work by blocking sunlight. No chemical weed-killers are required! The choice of mulch can depend as much on the plants in the garden as on which mulches are available.

Kinds of mulches for organic gardens

A mulch is a material that we spread over the soil and around plants. Many materials are used for mulch, even plastic sheeting, but organic gardeners may want to use materials that will improve the soil as they decompose.

Examples of these preferred materials include old leaves (saved from the fall), pine straw, pine bark nuggets, and bagged soil conditioners (which are ground up “forest products”).

Pros and Cons of Different Mulch Materials

Old Leaves have the benefit of being free. They might need to be stored over the winter, if they are needed for the spring or summer garden. Also, they are not super-long-lasting. However, “free” can override those minor problems. They do pack down over time, so pile them on a little higher than the depth you are aiming for. Do not use leaves from black walnut trees — they contain a compound that is toxic to some plants. Leaves dropped from other trees should be fine.

Pine straw mulch under a Loropetalum bush.
Pine straw mulch lets a few weeds through after several months.

Pine Straw is long-lasting, but it packs down over time, and it does seem to allow more weeds through than woodier mulches. However, near a house, pine straw has the advantage of not attracting termites. I use pine straw in shrub beds near the house.

Pine Bark Nuggets are long lasting. This makes them good for garden beds that will not need replanting any time soon. I use mini-sized nuggets, but others may prefer bigger pieces of pine bark. Over time, these will decompose and the mulch layer become thinner. Then, the bed will need to be re-mulched. If the bed needs to be reworked sooner, for any reason, the bark nuggets can be raked and removed, then re-used when the gardener has finished dividing/replanting or doing whatever task needed to be done.

Garlic growing in the garden, spacing is a grid pattern, and the plants are surrounded by a fine-textured mulch.
Garlic mulched with purchased soil conditioner.

Bagged Soil Conditioners are good to use in parts of the garden that need more frequent replanting. Soil conditioners are ground-up forest products (wood and bark), and they are highly variable between brands and even within brands, from year to year. This variability is caused by changes in where the pieces of tree are coming from. Regardless of the origin, the smaller size of the particles allows faster decomposition. This stuff doesn’t have to be raked away when reworking the garden; it can be turned into the soil, where it will help to improve the texture and water-management of our Southern clay and/or sand soils.

Will it help to start with a layer of cardboard or newspaper?

My own experience is that I can use a thinner layer of mulch, and still get fewer weeds, if I spread a thin layer of paper or cardboard on the soil first. Since mulch can become expensive, this is a big help for the garden budget.

However, researchers at Washington State University published a summary paper, that you can read as a pdf, that includes six reasons why using newspapers or cardboard is not always a great plan.

Here is a summary of the reasons they give:

  • The paper layers can become home to pests, including termites, which are attracted to cardboard.
  • Mini nuggets and other wood-based mulches, when used properly, do a fine job of stopping weeds on their own.
  • Wind can blow the paper and cardboard layers around.
  • If the paper dries out, it can repel water, stopping rain and irrigation water from getting through to the roots of your plants.
  • If the paper stays soggy, and it is on heavy clay soil, it may stop oxygen from getting through to the plant roots.
  • Paper and cardboard mulches are not attractive.

The most compelling reason to me, in the list above, is the one about termites, but the document seems to refer to the use of very thick layers of cardboard and/or paper that are not covered by another mulch material.

Most gardeners are not using multiple layers of cardboard around their plants, or super-thick layers of old paper. We also are not leaving it uncovered to blow around, mostly because of that last reason: it’s not attractive.

In the past, I have laid cardboard in a single layer under pine straw in the shrub beds near the house. The information in the Washington State document about termites’ being attracted to cardboard has changed that practice. Now, when I re-do mulch under those shrubs, I spread a thin layer of paper instead of the cardboard.

How to mulch the vegetable garden

If you decide to use paper under your mulch in the vegetable garden, these are the steps to follow:

  • Make sure that either all the plants are up and visible, or that the spaces where seeds are still below-ground are marked, so you don’t accidentally cover them up.
  • Remove any existing weeds.
  • Spread a thin layer of compost or a little fertilizer over the bed, to help the soil microbes whose job is to break down your mulch layers.
  • Water the soil, since mulch can slow the rate water soaks through.
  • Lay newspaper between plants, in layers just two-four pages thick; it shouldn’t touch the plant stems. Don’t cover places where you have planted seeds that are still under ground.
  • Water the paper. This holds it down so it won’t blow away while you’re working, but it also improves contact with the soil. Water will get through the paper faster if it starts out wet.
  • Spread your chosen mulch over the top. Keep it an inch or two away from plant stems.
  • Newspaper spread on soil between plants in vegetable garden.
    Thin layer of newspaper over the soil.
  • Mulch covers some newspaper in a vegetable garden.
    Water the paper, then spread mulch over the top.

Some weeds are tougher than others

Weeds that have large, long-lasting roots, like dandelions and the remains of shrubby plants, need to be dug out of the garden before any mulch is laid. They can rise up through a surprising amount of mulch.

Bermuda grass, which can be great as a Southern lawn, will come up through almost any mulch. I have seen it come up through contractor-grade weed barriers, through cardboard, through gravel. I have seen it grow up through Very Deep raised beds. It should be dug out of the garden before any mulch is laid.

The good news

Using mulch in the vegetable garden really can cut back on the task of weeding. Some weeds will probably come up around the edges of the garden and in any gaps that develop in the barrier created by the mulch, but the work of keeping weeds down will be greatly reduced.

Mulch also reduces water losses from the soil, which means the gardener can spend less time watering the garden. The past two summers, my garden has been fine with zero watering in the months of June, and July. Those were both generally “wet” summers here in the Atlanta area, but there were some dry stretches mixed in.

Another benefit of a mulch that decomposes fairly quickly, like soil conditioner or old leaves, is that they improve soil texture as they break down. As those mulch materials decompose, they provide some of the same benefits as compost. To read more about the use of compost in building good garden soil, see my blog post about the topic.

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