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Organic Garden Pest Control

18 June, 2019 by amygwh Leave a Comment

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)

These bacterial products are 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.

When to Harvest Summer Squashes

1 June, 2019 by amygwh 3 Comments

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.

When Compost is the Fertilizer

26 May, 2019 by amygwh 4 Comments

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.

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.)
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.)
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.)
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!

Bridging a Garden’s Hungry Gap

20 May, 2019 by amygwh Leave a Comment

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?

You can add yours to the comments section, to help your fellow gardeners.

Thank you for pitching in!

National Public Gardens Week

10 May, 2019 by amygwh Leave a Comment

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.

Stop Garden Weeds with Mulch

6 May, 2019 by amygwh 2 Comments

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 text 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.

Thin layer of newspaper over the soil.
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.

Garden Gifts for Spring

26 April, 2019 by amygwh Leave a Comment

Spring and summer can provide one or more gift-giving opportunities for gardeners. Choosing the right gifts, though, can be difficult. What will your gardener appreciate? The best place to start is with any tools or supplies that your gardener might have mentioned needing.

If, however, your gardener has not offered any suggestions — or maybe has, but you’ve forgotten what they were — here are some ideas that may help:

Gifts for the gardener

Oilcloth half apron with three gingham check pockets and yellow floral background. — PHOTO/greatergood.com

A cheerful and practical half-apron with roomy pockets, made of water-repellent oilcloth is fun to wear and keeps seed packets and small tools from getting lost in the garden. I have a similar apron that a gardening sister bought for me one year at a craft fair. I love mine! Your gardener might like one, too. The apron linked here is sold by an animal rescue group, with proceeds going to support its work.

Mini pruners from Corona tools. A 5-inch long pruning tool might not seem super-practical on first sight, but I use mine to harvest greens and vegetables like peppers. The small pruners are easier to keep in my apron pocket (see above) than larger pruners, and they are also easier to use in tight spaces than the kitchen shears that some gardeners use for the same purposes.

Fall Garden Planning book explains how to choose crops, create a schedule, and prepare the garden for fall planting.

My Fall Garden Planning book can help your gardener prepare for the whole gardening year, which extends well into fall and winter for gardeners in the Southeastern U.S. I have been told that the book is easy to both read and understand, and that it’s helpful. Of course, that was the goal!

For gardeners who tend to “walk on the wild side”, the book The Wildcrafted Cocktail would be a fun addition to the cookbook collection. On days when the weather is not great for gardening, the gardener can spend enjoyable time in the kitchen with foraged foods (including daylily buds – which many gardens can provide) preparing elements of the various cocktails.

A Gift for the garden

Texas Tomato Cages are pricey, but I love mine. These are wide enough for good stability and tall enough to contain most tomato plants. The cages come in two sections that stack together (securely), and here is another great feature: they collapse to nearly flat for storing when not in use. They can be hung up — out of the way — in the shed or garage in winter.

If your tomato plants tend to erupt out the tops of your cages, extensions are available to make these even taller. You can see one of the cages – without an extension – in my earlier blog post about planting tomatoes. We also use the Texas Tomato Cages at the Plant-a-Row-for-the-Hungry garden for which I am a volunteer.

If none of the above seem like a good fit for your gardener, check out the gift ideas provided by a couple of my gardening friends:

From Miss Smarty Plants – Garden Gifts to Make Mom Smile
From The Washington Gardener – (to be added soon)

Growing Summer Salad Greens and Potherbs

23 April, 2019 by amygwh Leave a Comment

Many of the most well-known salad greens, like lettuces, and potherbs such as spinach and collards, are cool season vegetables. That means that they do not stand up well to summer heat, especially the intense and humid heat of the Southeastern U.S.

Jewels of Opar plant with pale green, slightly succulent leaves, growing near the base of a wooden half-barrel. — Jewels of Opar is both beautiful and edible.

However, the onset of summer does not necessarily mean the end of garden salads and cooking greens. It does, though, mean that our summer salads and cooking greens might look and taste a little different from those we enjoy in cooler weather.

What is the difference between salad greens and potherbs? In general, we eat the salad greens raw and the potherbs cooked. Some greens can be used both ways. The list below is not a full list of all the possibilities; it is a start, though, to help diversify our gardens and our diets.

Salad greens we can grow in summer

Lettuces

In the Southeastern U.S., growing full-sized summer lettuces — that are not too bitter to eat — is difficult in a home garden. However, some gardeners in the Southeast cannot imagine life without garden-fresh lettuce. The good news is that it is possible to keep growing lettuce here, in the summer heat, but the gardener will have best success when harvesting the lettuce as “baby greens”.

That means harvesting the lettuces when they are only about four inches tall, letting them regrow once (maybe) for a second harvest, then starting over with another bunch of seeds. Lettuce plants in the garden eventually will turn bitter in the summer heat. Planting a new patch of seeds every few weeks lets a gardener harvest fresh lettuce that is still sweet.

Planting the lettuces in a spot that gets afternoon shade, with rich moist soil, and not allowing the soil to dry out, can help delay the bitterness.

Chicories can be grown and used the same way in summer – harvested small, grown in rich, moist soil, in afternoon shade, to minimize the bitterness.

Purslane and Jewels of Opar

These plants are grouped into the same plant family: Portulaceae. Both have leaves that are a little tart, or maybe lemony in flavor, and succulent — plump with an interesting interior that skirts the edge of slimy.

Purslane pops up in my garden on its own. I have never planted seeds for it, but buying seeds is possible if this plant doesn’t just magically appear in your summer garden. Baker Creek sells seeds for both green purslane and golden purslane. They grow well in full sun.

Purslane seedlings in the garden.
Purslane plant in a space between leaves of a squash plant in the home garden.

Jewels of Opar (see photo near top of this article) is a cultivated plant that self-sows in many yards after the first plant becomes established. I have written about Jewels of Opar in a previous blog post, but the best news is that the plant is attractive enough to grow in a flower border. If your garden is in the front yard, this is a salad green to try.

Parsley

The strong flavor of parsley is not a favorite for everyone, I know, but this green is an essential ingredient in the Mediterranean salad known as Tabbouleh. The Lebanese version includes a lot more parsley and less bulgar wheat than some versions, and it is a good argument for including more parsley in other kinds of summer salads.

Parsley may be my favorite summer salad green. My garden has four parsley plants in it right now, growing to hugeness.

Potherbs we can grow in the summer garden

Swiss Chard

Some Swiss Chards languish in the summer heat, but I have had good success with a variety called ‘Perpetual spinach’. If you enjoy beet greens, this is an excellent similar-flavor substitute for summer.

Smaller leaves, harvested while still tender, can also be used as a salad green.

Amaranth

Leaves of amaranth wilt pretty quickly when they are cooked, so have the garlic chopped and ready to go before adding the leaves to a hot pan with olive oil. Like for many other plants, new small leaves are tastier than older, larger leaves.

Some varieties of amaranth grow very tall and are cultivated for their seeds, rather than as greens.

Look instead for a variety like Baker Creek’s ‘Green calaloo’ or ‘Chinese multicolor spinach’. These are cultivated for their more delicious leaves.

Malabar spinach

Many years ago, when I was growing malabar spinach, our substitute mail-carrier was from Barbados. One day, when she was delivering the mail, she stopped to ask about our garden. She said that our malabar spinach was the green her mother cooked for her family back home. She called it REAL spinach. I quickly harvested a large pile of leaves for her to take home, and told her to stop by any time for more.

Once established, this crop is a vigorous vine. Be sure you have plenty of room and a strong trellis before planting this one. The thick leaves are more mucilaginous inside than most cooking greens, but the slimy aspect is lessened with cooking. According to our mail carrier, adding a few chopped leaves to soups is a good way to work your way toward eating them as a stand-alone dish, if they don’t appeal at first.

I never managed to love this crop, so we don’t grow it any more. I have met, though, plenty of gardeners who do love malabar spinach and who can’t imagine not growing it in the summer garden.

How to Plant a Tomato

12 April, 2019 by amygwh

Most of the work of planting takes place before the actual planting day; the work is in soil preparation and careful selection of your tomato variety, finding one that will do well in your yard and that makes delicious fruits.

Once that part is done, though, there is more to consider. I made a little video that tells about setting a tomato transplant into the ground and how to defend it from cutworms. Here is the video:

The tomato that I planted today is a Park’s Whopper. I don’t usually plant my tomatoes this early, but I know that plenty of gardeners are planning to do just that this weekend. Hopefully, the video will be helpful.

After the planting, the protecting

After planting the one tomato plant, I laid a thin layer of newspaper on the soil around it, to keep fungal spores from splashing up onto the leaves from the soil below. Then I spread a thin layer of pine bark mulch over the paper, to hold it down.

A thin layer of newspaper helps protect the plant from soil-borne leaf diseases.
Thin layer of pine bark mulch holds the newspaper down and adds another layer of protection.

When the plant looked well-defended from soil-borne leaf diseases, I wrapped the lower part of the cage with clear plastic sheeting. The reason for the wrapping was primarily to protect the plant from too-low temperatures.

Tomato cage with lower portion wrapped in plastic helps protect early-planted tomato from cool night temperatures.

We are still having some nights with temperatures in the 40s. On the coolest nights, with the sides already protected, it will be easy to cover the top to hold in some extra heat.

The peppers and remaining tomato plants will get planted in another week or so.

For now, I will keep bringing them into the house on cool nights. However, they will all get the newspaper and mulch layered around them after planting.

Growing (and Eating) What’s Good for the Garden

7 April, 2019 by amygwh

New gardeners often are advised to grow foods that they and their families like to eat. It makes sense. Why grow tomatoes if no one at home will eat them? That advice, though, is less firm for gardeners who have been working their soil for a few years. Longer-term gardeners should consider branching out a bit, with regard to what they grow. Here is why:

Different crops can improve your crop rotations

Crop rotation is the practice of growing different kinds of crops in succession within a growing space. “Different kinds” here means plants from different plant families. An example of crop rotation, to illustrate the practice from one space in my garden, is this: kale (fall/winter), followed by peppers (summer), followed by garlic (fall/winter).

Why should you be concerned about your crop rotations?

Bowl filled with shelled cowpeas surrounded by garden vegetables including okra, tomatoes, and peppers. — Cowpeas, in the bean family, help diversify my crops in summer.

University of North Carolina’s article, Advantages of Crop Rotation, explains that rotating crops can reduce buildup of pests and diseases. It can also improve the balance of nutrients in the soil and improve soil structure.

Organic gardeners, especially, who may see themselves as stewards of the soil, will find that crop rotation is a practice that can enhance their gardens.

A chef argues for eating more kinds of crops

I remember reading a Yale Environment 360 interview with chef Dan Barber who explained how he came to understand that supporting sustainable agriculture can mean learning to eat new crops.

The central example discussed in the interview was a farm that was growing emmer wheat, an ancient variety that Barber was excited about using in recipes. This is the relevant bit in the interview:

…I was standing in the middle of a field, and all of a sudden discovered that he [the farmer] was growing very little wheat, and that instead he was growing a whole suite of lowly grains like millet and buckwheat and barley, and leguminous crops like Austrian winter peas and kidney beans. He was growing a lot of cover crops like vetch and clover. And they were all meticulously timed and spread out among the 2,000 acres I was standing in the middle of. And that’s when I sort of had this agricultural epiphany. But it led to this gastronomic epiphany, which was that here I was as a farm-to-table chef waving the flag of sustainability and realizing that I wasn’t supporting most of the farm. In the case of Klass [the farmer growing the emmer wheat], he needed these lowly crops and cover crops and leguminous crops because his soil health needed it to grow wheat. You couldn’t get the wheat unless you grew all these other crops. And you had to time it in this way that brought the fertility to the soil to give you this incredible tasting wheat.
Diane Toomey, How to Make Farm-to-Table a Truly Sustainable Movement, interview with chef Dan Barber, Yale Environment 360, 15 Sept. 2014

Most of us are not going to develop elaborate rotations for the production of emmer wheat, but the interview made me feel like less of a loon for growing – and learning to prepare and eat – crops that are not my favorites, all because I thought they’d be good for the garden.

Adding more plant families to the rotation, for home gardens

An example of adding beets

Red beet with red-veined green leaves growing in soil. — Garden beet in April.

Years ago, I decided to expand my spinach/amaranth family plantings by growing beets, even though I didn’t really like beets. I could have planted more spinach, instead, but the phosphorus level in my soil was a little high. I knew that a root crop like beets would use up some of that extra phosphorus, helping to rebalance the nutrients in my garden’s soil.

Over time, as a result of this decision, I learned how to prepare beets in a way that Joe and I actually like. Now, beets are just one more good food that we look forward to bringing in from the garden.

I have worked on collard greens in the same way, but with less success. The good news is that Joe likes them.

Why grow collard greens?

A good reason to grow collard greens is that collards (and mustards) help suppress the root-knot nematodes that are such a big problem in Southern soils. At the garden/farm where I used to volunteer, the winter mixed-greens crop of collards, mustards, kale, and radishes was called a “fumigant” crop for the good work it does in cleaning up the ever-present nematode pests in the soil.

These greens can stay in the ground all winter long in the South, harvested leaf by leaf, so they work on the soil for many months. Tilling in the remaining leaves and roots about a month before spring planting just frosts the cake of their beneficial effects.

Plant families for garden crops

The list of plant families that include food crops, to enhance your own garden crop rotations, is large. Here are examples of plant families and some crops in each one:

Tomato family – tomato, pepper, eggplant, potato, tomatillo
Cabbage family – cabbage, broccoli, kale, collards, mustards, radish, turnip, kohlrabi, Brussels sprouts, cauliflower, arugula/rocket
Bean family – bush beans, pole beans, Lima beans, peas, Southern peas, cover crops like clover and vetch
Onion family – onions, garlic, shallots, chives
Carrot family – carrots, parsley, cilantro, parsnips, dill, fennel
Spinach family – spinach, Swiss chard, amaranth, beets, Good King Henry
Squash family – cucumbers, summer squashes, zucchini, winter squashes, pumpkins, melons
Sunflower family – sunflowers, lettuce, chicory, radicchio, escarole, endive
Mallow family – okra, roselle
Morning glory family – sweet potatoes
Mint family – mint, basil, oregano, thyme, anise hyssop, rosemary, sage, marjoram
Borage family – borage
Grass family – corn, wheat, rice, oats, lemongrass
Buckwheat family – buckwheat, French sorrel (and rhubarb, which is not a plant for the South)

Growing some chicories

Pale green lettuces and dark red radicchio plants growing together in a garden bed. — Radicchio (right) is a kind of chicory, which is in the same plant family as lettuces (left). Growing them together makes crop rotation simpler.

Personally, I would like to see more gardeners branching out a bit into the unknown, in terms of crops. That is why I took seedling chicories to the Soil3 Garden Show, to give away with a handout of information about chicories.

I have found that these plants are relatively pest-free in our area. For organic gardeners in the South, pest-free crops are an amazing gift! Chicories also have deep roots, which can help break up heavy soils and can bring up nutrients from deeper soil layers.

Clump of 'Italiko rosso' chicory - upright leaves are dentate and have red veins. — ‘Italiko Rosso’ chicory in the fall, ready for harvest to use in salads or on pizza.

In addition, they are useful in the kitchen as greens, which we all probably need to eat more of (chop some up to put on your pizza), and the roots can be roasted to make a coffee substitute. If the plants stay in the garden over a winter, they will produce a tall stem with blue flowers, in spring or early summer, that will support many pollinators.

Not everyone will appreciate the bitter flavor of chicories, but if you like the flavor of radicchio in your salads, you may like other garden chicories, too. The very first one I grew, Italiko rosso (which Baker Creek labels as a dandelion, possibly because of its leaf shape), is still a favorite.

Hope your gardens are all growing well!

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