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What Caused my Tomato Plant to Wilt, Part 2

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One of my two mature, productive tomato plants wilted last week. Surprise! My previous article (was it just five weeks ago?) about wilting tomato plants was more timely than I knew.

This is the story of what happened.

Wilted, green top of tomato plant
The whole plant had wilted. See the droopy leaves up top?

We had rain. The rain in our area has been patchy, so the rain in my yard may not be like the rain in your yard, but one day we had about 10 hours of steady rain. When I looked out the front windows the next morning, thinking that the garden would probably look great after all that water, I saw that one of my tomato plants had wilted.

I thought back to my previous article about the steps to follow, to figure out what happened to my plant.

At the very least, I can say with confidence that dry soil was not the cause of the wilting.

The plant hadn’t wilted only on one side, and it wasn’t merely slightly droopy. All the leaves on the entire plant were hanging limp on the branches, and smaller branches were sagging.

Tomato stems suspended in jar of clear water.
The streaming test for bacterial wilt was negative.

At first, I thought “cool, bacterial wilt”, since the wilting was so sudden.

Checking for Bacterial Wilt

This is a disease I have seen only once, but I knew that one sign of bacterial wilt was sudden wilting of the entire plant.

Often, this wilting takes place in hot weather and moist soil.

I trimmed off leaves and branches to do the bacterial wilt streaming test. If bacterial wilt was the cause, then white cloudy ooze should stream out of the branches when they were suspended in water.

When the first couple of leafy branches failed to produce the white cloudy streaming that I expected, I cut a thicker section of stem to add to my jar of clear water, to see if maybe I just hadn’t used a big enough section of branch. Ten minutes later, the water was still clear.

Looking at base of the plant for more clues

Then, I finally looked at the base of the plant, where the stem emerges from the ground. This was when I thought “uh oh”. There was white fungus-looking stuff right near the base of the plant and climbing up the stem.

White stuff on ground and on two green stems growing through the white stuff

To be honest, this is probably a bigger problem than bacterial wilt would have been for the future of my garden. My knowledge of white fungus climbing up stems from the ground leads me to think the fungus is Southern Blight. (Link is to a pdf about Southern Blight from University of Kentucky)

White fungus climbing up green tomato stem and extending into nearby soil

Lots of fungal diseases are host-specific. That means that they can infect only a limited number of crops. Southern Blight, on the other hand, can infect many kinds of crops.

How can I reduce future damage from Southern Blight?

I already removed the plant, including as much of the root system as I could. University of Kentucky’s information (linked previously) recommends removing the soil in that area, too, to reduce the number of reproductive bits, called Sclerotia, in the garden.

The next recommendation that organic home gardeners can follow is to grow plants that can resist Southern Blight in that area for a few years.

Resistant plants, according to University of Florida and Louisiana State University include woody plants, ornamental grasses, corn, and wheat.

The other recommendation is to raise the soil pH a bit. The fungus grows more slowly in higher-pH soils.

The good news: no evidence of root-knot nematodes

Smooth roots from dug-up tomato plant
Smooth, tapering roots show no evidence of root-knot nematodes.

If there were root-knot nematodes adding to the damage, the roots would look lumpy. Maybe other gardeners are not as relieved as I am to see this lack of lumpiness, but some years my garden is seriously affected by the nematodes.

Where did the Southern Blight come from?

This is hard to know. My garden has never, until now, shown any sign of harboring Southern Blight. The disease can travel on infected plants, mulches, soil, and contaminated tools. I am thinking that it could also be spread by ground-scratching birds, but they are not mentioned in any of the publications I checked.

A new tomato plant growing nearby

At the end of June, when we returned from five weeks of travel and before we drove across Texas to visit family in the Austin and Houston areas, I planted two tomato seeds in the garden. Luckily, they are in a separate garden bed from the blighted plant.

I set the seeds inside a collar formed by a paper cup that had the bottom removed. The collar was to help hold moisture and to protect the seeds from being eaten. I watered the area well before we got in the car and headed west.

Small tomato plant next to a stake, and several Swiss chard plants planted in an arc nearby
Healthy, young tomato plant was started from seed in late June.

Amazingly, when we got back from our 8-day tour of relatives, a little tomato plant was standing where I had planted those two seeds.

I had planted some Swiss chard and a leaf-amaranth in the same little garden area, and they were coming up, too. A caterpillar of some kind found those to be delicious, so I had to replant the greens, but all is looking good now.

That little tomato plant has flowers on it today. If all goes well, there will be more garden-tomatoes coming into my kitchen by late September, and, hopefully, the potential disaster of Southern Blight will not be causing too many more problems.

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.

Summertime Adventure

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Anyone who has been reading this blog for very long may have been wondering when I would get around to telling what I’ve planted in my garden this year. Usually, I spend most of January and February all in a tizzy over seed catalogs, trying to decide what new crops will go into the garden in spring.

This year, I tried not to look too closely at the seed catalogs that arrived in my mailbox, because I knew that I would be away from home for much of the summer. Reading them could have caused a bit of mental conflict!

My food-garden right now has a lot of herbs in it, the big strawberry patch, garlic and shallots planted in early winter, a few lettuces (unless a neighbor has eaten them)

Plenty of strawberries in the yard this year!

View from where I am writing today.

Container gardens: Not many veggies, mostly herbs and flowers.

Wonderful place not far outside of town!

and flowers for the local pollinators. There are no summer crops in the garden because I am in Italy!

I left an assortment of college students in charge of the house and the lawn-mowing, and the only plants they are tending are two houseplants and the big container/planter by the front door.

When I get home, I can start thinking about the fall garden (and a whole lot of weeding, I expect). It has been weird, though, to not plant any vegetables. I have grown vegetables in my yard in NW Georgia every summer since 1991.

I am looking forward, while I am in Italy, to learning more about gardening here. On a walk outside the city walls this weekend I found a large garden center, and even though my Italian language skills are sketchy and the English language skills of the people at the garden center are only a little better, we managed to communicate well enough.

The garden center features many annual and perennial flowers, but I also saw trays of vegetable transplants and pots of herbs. I will be going back again in the next few weeks to see/learn more.

Already I have seen that anyone with even as little open ground as a 5×10 foot patch is growing at least an olive tree. Larger spaces often include other fruits. I’ve seen quite a few cherry trees (sweet cherries, that don’t do well in the humid Southeastern US), a few other fruit trees, and outside the walls of the town and in parks, there are umbrella pines that produce big pine nuts that are good to eat. It is great to find that so many people grow at least a little food!

The center of the hilltop town I am in, Montepulciano, is very paved, which accounts for the large number of container gardens, but farther down the sloped sides of the town there is more unpaved space, and some homes that have little yards. One yard that I saw on Friday includes a chicken coop, some fencing around a planting of tomatoes, a couple of olive trees, and a peach or apricot.

On another walk, I found the local biodynamic farm, Fattoria San Martino. I am hoping to make an official visit soon, complete with lunch reservation, and I will be reporting back on what I learn there.

Hope that all your gardens are doing well! If garden problems crop up, though, please feel welcome to ask about them through the comments link of this blog.

-Amy

Georgia Organics Conference, Part 2

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Really, the very best parts of attending something like the Georgia Organics conference are meeting new people and hearing those peoples’ thoughts about food and our food system. This is probably an example of what is called “confirmation bias,” where we seek out and bend information in ways that support our own world view, but I did leave the conference with an upbeat feeling about local food production in Georgia.

Cover of our conference schedule. It is actually green. PHOTO/amygwh

After my friend Electa and I arrived on Saturday morning, we signed in, then went through the breakfast line and looked for a place at a table.

We wound our way through the big breakfast area to a table that had only one woman and her young son seated there. Over breakfast we learned that they both had completed a growers bootcamp put on by Habesha Atlanta (but held in Augusta), and they were starting their own small food-growing operation.

While we ate and talked, more people who had participated in the same bootcamp, and who had begun working to grow some good food, joined us. This was a GREAT way to start the conference!

Throughout the day, we met and spoke with other people who had established small (1/2 acre or less) orchards and veggie farms and small chicken production operations in urban and suburban areas throughout Georgia.

Then one speaker (could have been GA’s Ag commissioner Gary Black; my notes are sketchy here), in talking about Georgia’s food system, listed big farms, medium farms, small farms, and home gardens as all contributing to our food system.

Home gardens! It was so great to hear these recognized as an important element of food production in the state.

My dream, of course, is that everyone finds a way to grow at least a little food. Our individual production may be small, but it all adds together.

Georgia Organics Conference, Part 1

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Yesterday, early in the morning, I drove across Atlanta with my friend Electa to the Georgia Organics Conference, which was being held at a convention center near the airport. We had a fun day, met people who grow and love good food, and learned lots.

Cover of the Conference Schedule. In real life, it is green.

Eight different topics were presented in each time slot during the day, and they pretty much all looked interesting and potentially useful. However, picking the topic to see for our first session easy, because my friend Terri Carter was presenting about Food History in the South.

I was especially interested in the maps of trade routes she showed us and in the role of failing economies in influencing which foods were adopted into the “mainstream” diet. 

At other presentations during the day, I wrote down ideas/thoughts that could help home gardeners. This is a not-so-short list:

  • Sustainability starts with the seed. Choose varieties that are disease resistant and that don’t need pesticides.
  • In a small farm or garden, “diversification hedges your bets.” Grow more than one variety of each vegetable.
  • In a small space, ‘Georgia Rattlesnake’ watermelon, which produces Very Large Fruits, might not be the best choice, even though its flavor is spectacular. The plant covers a lot of ground to make those enormous fruits.’Ice Box’ and ‘Moon and Stars’ have a much lower brix reading than ‘Georgia Rattlesnake’. You might want to try different smaller varieties than those two.
  • Look for open pollinated varieties when you can, since these tend to have a diverse genetic background. Even in bad years, some of these may survive and produce food.
  • Trellising saves a lot of space and can reduce fungal diseases on leaves and fruits by getting them up off the ground.
  • In trials looking at yields of tomatoes on different trellising systems, cages gave the most pounds of tomatoes per plant. 
  • For blackberries, our farmer-presenter got higher yields on North-South trellis rows than on East-West trellis rows.
  • The same guy shears off the tops of his tomato plants about a foot above his trellis system (he uses a fence system, of wire fencing on T-posts, for his tomatoes).
  • There are no effective sprays to stop diseases in organic systems. Serenade and Sonata sprays may slow down the mildews, but getting good coverage of the leaves is not easy, and these products need to be re-applied every 7-10 days.
  • Neem is not helpful for squash bugs.
  • Avoid composting plants that have root diseases, but composting plants that have leaf diseases is okay. 

More thoughts prompted by the conference will be in my next post. Meanwhile, I have completely ignored my own good advice and planted out some lettuce seeds. The weather is seductively warm, and I am ready for spring!

 

Can You Dig This? – The Movie

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On Tuesday evening, Joe and I went to see the movie Can You Dig This at a one-time-only screening. The movie, set in LA and featuring Ron Finley and other area residents, shows how the simple, basic act of growing food can transform lives.

The movie, in addition, was a powerful reminder that not everyone has access to health-giving produce, straight from the garden, and I know I am very fortunate in being able to grow food in my front yard.

We saw the movie at a theater inside the perimeter, and after the movie, people who are very involved in urban farming and the Atlanta local-foods movement stood up to say a few words about urban farming in the metro area.

One of the speakers was Eugene Cooke, of Grow Where You Are. I love this guy’s vision of integrating farming more fully into communities, but he seemed to be having trouble containing some of his frustration as he spoke at the screening. He is hoping that more growers step into leadership in the urban-ag arena, but right now there are many other players who are poking their fingers into his pie (I know – mixed metaphors, but I am hoping the point comes across). Since Eugene follows agro-ecological principles and uses Veganics as his guide, it is likely that a lot of people who visit his farm don’t really understand how much of his work goes into building and maintaining the soil.

Some of our Asian persimmons – Ichi Ki Ke Jiro.

Other speakers included someone from the Georgia Farmers Market Association,  Dr. Ruby Thomas who is a pediatrician promoting veganism for her patients (her website is called The Plant-Based Pediatrician), a representative from Truly Living Well who said that the group would be increasing its outreach to children and families in the upcoming year, someone from the Georgia Food Bank (I think … my notes are getting more sketchy as I go along) who mentioned the work of Georgia Food Oasis,  Robby Astrove who has headed up the planting of many, many fruit trees in the metro-area, and last of all, Cashawn Myers of Habesha, whose chance to speak was cut short by the beginning of the next movie. I had hoped, actually, to hear what Cashawn would say, since two of my friends have been through his farmer training program, but I will have to wait for another opportunity.

The refrain that ran through the movie and ended the evening was “Just plant some shit!”, and there already is a planned “Plant some shit day of action” on December 15,  from 2-4 p.m., in Edgewood at the corner of Whitefoord and Hardee. The flyer I picked up on the way out of the theater specifies “Dress to get dirty, bring gloves, water, & garden tools.”

Meanwhile, at home, I am reaping some of the rewards of having “planted some shit” already. Joe brought out a ladder today to harvest the rest of our persimmons, and we have plenty of cool-season vegetables from the garden still adding to our meals.  Feeling very blessed…

Compost Contemplations

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Last week was “International Compost Awareness Week,” so compost was uppermost in my mind for much of the time. One major aspect that’s been on my mind is that, even though my six pet bunnies add a lot of old hay and bunny manure to my compost pile every week, there still isn’t enough compost for my whole garden, and my garden is not large.

I read once that the average WWII Victory Garden encompassed ~600 square feet. My vegetable growing space is just a little over half that. Remember — Victory Gardens during WWII provided about 40% of this nation’s produce at a time when that production was sorely needed. That is a huge amount of productivity!

The U.S. could do that again, if needed, but it would take a lot of compost.  Maintaining a warren of rabbits in my garage is, apparently, not the answer to the question of where all the needed compost is going to come from. You may be asking — “why is compost needed in such large amounts?”

Part of the answer would lie in the brick-like consistency of Georgia clay in summer, or the non-absorptive properties of soils that are mostly sand.  Even for conventional/chemical gardeners, compost can improve the physical properties of very poor soils.

Gardeners working in the kinds of subdivisions in which all the soil was rearranged by giant machines before construction even began, removing the topsoil and putting it who-knows-where, will totally understand what I mean by “very poor soils.” Many of us begin without any real topsoil at all!  Compost improves moisture retention, nutrient availability, and biological activity in these soils.

For organic growers, abundant compost is basic to the whole process, with the “biological activity” part being of utmost importance, since without the underground microbes and their slightly larger associates, there would be no nutrients available for plant growth.

Even beyond the productivity gains that can come from nourishing the teeming billions of lifeforms underground, yet another reason to compost may lie in the ability of that compost to help move carbon underground. In my scanning of the morning news this past week, I read a surprising headline: “First time in 800,00 years: April’s CO2 levels above 400 ppm”. We all knew that was coming, but it does seem a little soon.

Couple that headline with an article that I had seen through Resilience.net, originally published at Yale Environment 360 — “Soil as Carbon Storehouse: New Weapon in Climate Fight?” — and compost is looking even more like the “black gold” that some gardeners call it, even though compost isn’t specifically mentioned in the article. Instead, it mentions other practices that could help store carbon in the soil:

“…replanting degraded areas, increased mulching of biomass instead of burning, large-scale use of biochar, improved pasture management, effective erosion control, and restoration of mangroves, salt marshes, and sea grasses”

Much further along, the article mentions the important role of fungi in storing carbon in the soil:

“…scientists from the University of Texas at Austin, the Smithsonian Tropical Research Institute, and Boston University assessed the carbon and nitrogen cycles under different mycorrhizal regimens and found that plants linked with fruiting, or mushroom-type, fungi stored 70 percent more carbon per unit of nitrogen in soil.”

Using composts and degradable mulches can do a lot toward welcoming the right kinds of fungi to a garden.

The article was aimed more at larger scale agricultural activities, but that doesn’t mean that gardeners can’t do their part to help out.  If more of us are more intentional about what happens to the carbon that flows through our lives, it certainly can’t hurt.

This is my birthday month, and one of my best buddies, as an early birthday gift, took me to a book signing for Farmer D’s new book, Citizen Farmers (and she bought me a copy of the book, for Farmer D to sign!). One great aspect of the book is its focus on compost. Really, all gardening should start with compost, but most garden book don’t make that point so emphatically.  Farmer D lists, right in the introduction, his citizen farmer basics, and number one on the list is “Make composting a way of life.” That sounds like a very good idea.

What is Organic Gardening?

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In my not-vast-but-not-tiny experience of talking with other gardeners, I have found that the word “organic,” as applied to gardening, seems to be not well understood. There’s a good reason for that; the definition isn’t easy or brief, but I am offering here a simplified explanation.

When we refer to organic gardening or farming, we mean growing food using a specific set of principles and inputs that are as close to the natural state as possible in a way that maintains a living soil with a diverse population of micro and macro-organisms. Spraying anything for pests and diseases is the LAST option for resolving garden problems, even if an organic-approved spray is available.

There’s some significant overlap between organic and conventional gardening. Plants need nutrients, soil/support, water, sunlight, air in the root zone, and good air circulation around the leaves and stems, and those are the basics that good gardeners using both systems provide.

There are huge differences, too. In conventional gardening, soil is viewed as a substrate with important physical and chemical properties that affect how nutrients and water move through the soil. Fertilizers tend to consist of salts of various essential nutrients, which are available for uptake by plants as soon as they are dissolved in water. Many chemical options are available for diseases and pest control, and correct use of inputs (fertilizers, for example) depends on some simple math and basic guidelines.

In organic gardening, soil is viewed as home to an abundant and diverse community of tiny life forms. The physical and chemical properties are important, too, but more important is that nutrients are made available when released through the action of those microbes, fungi, and other tiny lifeforms that live in the soil. This action is, essentially, the decomposition of organic matter and other soil amendments. Maintaining the health, abundance, and diversity of this community underground is essential to having a productive organic garden. There are very few spray-on options available for pest and disease control, and those that are available don’t work all that well (in general). Choosing inputs — manures, composts, and rock powders, for example — to maintain the abundant liveliness of the soil, takes careful thought and planning.

Looking at the differences between the two systems, and the absence of absolutes — or simple prescriptions for what to do next — in going organic, the big question is “why would any sane person choose organic gardening?”

Well, I can think of plenty of reasons. To start:

1. living near an ecologically sensitive area (like a stream) and not wanting to mess that up
2. wanting to provide as little support as possible for “big agriculture,” for one reason or another
3. being majorly into DIY (doing it yourself), because with organic, you can
4. having small children or pets, and as a result not wanting to risk storing hazardous chemicals 
5. having a serious sensitivity to a wide variety of chemicals, and wanting to be free of rashes, fatigue, etc.
6. being concerned about losses in populations of bees and other pollinators
7. having a tendency to put food in your mouth – unthinking and without washing – while in the garden, or having a child with the same tendency
8. wanting to eat organically grown food, while at the same time having a tight food budget
9. being concerned over some of the newer, systemic pesticides used on commercial crops that can’t be washed off, because they are taken up inside the cells of the plants

It is difficult to just go partway organic. Using composts and manures can be a big help in conventional gardening, improving water retention/drainage and nutrient flow/abundance, but using conventional fertilizers in an organic system is more likely to have negative effects. Some members of the below-ground community of micro and macro-organisms are very sensitive to the fertilizer salts; they will do less well if conventional fertilizers are added. If the action of those lifeforms is the major source of nutrients for your garden, their doing less well will be a problem, because your crops will also do less well.

Going organic also means that most pest and disease control is done through prevention, involving crop rotations, disease-resistant plants, avoidance strategies, cover crops, promotion of beneficial insects, and other strategies that require advance planning.

This sounds supremely complicated, but plenty of gardeners seem to be managing organic food production quite well, and we are fortunate in having a lot of information and other resources to help us along the way.

Benefits of Crop Rotation

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I have understood for a pretty long time that crop rotation, which involves the practice of NOT planting the same crop (or crops in one plant family) in the same location year after year, is important for a variety of reasons.

One reason is that plants in one family often are attacked by the same pests and diseases. Rotating out of a particular space, and planting crops from a different family there instead, can help reduce the buildup of diseases and pests that attack crops in one plant family.

Another reason is that plants in one family often make similar nutrient demands on the soil. Jessica Strickland of North Carolina Cooperative Extension, in a May 2013 article, wrote:

“Vegetables in the same family are similar in the amount of nutrients they extract from the soil, so over time planting the same vegetables in the same spot can reduce certain nutrients in the soil. If the same family of vegetables is planted every year in the same location, insect and disease problems continue to increase and soil fertility drops. Using pesticides and fertilizer could provide little help but over time they would not be able to keep up with the increasing problems.”

Also, rotating to some particular crops can help reduce a pest problem that already has built up to damaging levels. An example pest is root knot nematodes, which can lower productivity of a crop pretty dramatically – if they don’t actually kill the plants outright. A population of these soil-dwelling pests can be lowered by planting a bed solidly in one of the nematode-repelling marigolds or in a grass-family crop like rye, wheat, or oats.

What I didn’t know until recently is the effect of crop rotation on the diversity of soil microbial life, the maintenance of which is so integral to successful organic gardens. In the Science Daily article “Why crop rotation works: Change in crop species causes shift in soil microbes“, Professor Philip Poole of the John Innes Centre in England is quoted as saying,

“Changing the crop species massively changes the content of microbes in the soil, which in turn helps the plant to acquire nutrients, regulate growth and protect itself against pests and diseases, boosting yield.”

Professor Poole added: “While continued planting of one species in monoculture pulls the soil in one direction, rotating to a different one benefits soil health.”

Yet another good reason to plan a careful rotation in the veggie patch.

For Healthier Fruit Flies, Go Organic

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Every now and then, the big debate over whether organically grown food supports an eater’s health more than food that’s conventionally grown rages anew, but a recent study suggests that, regardless of the effects on human health, organically grown foods do improve fruit fly health.

As a gardener whose kitchen in late summer and early fall typically becomes home to a whole lot of fruit flies, I am not sure this is the best of news. Most of the odds and ends in my compost pail are from organically grown produce, which means I am just making the annual infestation worse.

I read the news in an article titled Fruit Flies Fed Organic Diets are Healthier than Flies Fed Nonorganic Diets, Study Finds, which appeared on the website of Science Daily. The study was led by a high school student in the lab of biologist Johannes H. Bauer, at Southern Methodist University in Dallas, Texas.

 Here’s the quote that pretty much says it all:

“To our surprise, in the majority of our tests of flies on organic foods, the flies fed organic diets did much better on our health tests than the flies fed conventional food,” Bauer said. “Longevity and fertility are the two most important aspects of fly life. On both of these tests, flies fed organic diets performed much better than flies fed conventional diets. They lived longer, had higher fertility, and had a much higher lifetime reproductive output.”

In other words, I probably either need to learn to get along with the fruit flies, or I need to keep the compost pail in the fridge until its contents are taken out to the compost pile.