Category Archives: Research Spin-off

Compost to control plant diseases (revised)

November 23, 2008 by The Manic Gardener

Field tomatoes stricken with P. nicotianae Breda de Haan
USDA Forestry image fr. Division of Plant Industry Archive
Florida Dept. of Ag. and Consumer Services

So a day or two ago I was innocently researching away about compost and just for fun, hit the Google ‘scholar’ option to see what came up under the wide-open search term “compost.” (Toe surgery confines me for the moment to whatever I can find on the Internet; even the University library six blocks away is too far).

Lo and behold, I found myself looking at a number of articles dating back to the eighties and continuing right up to the present day about managing diseases with compost. Slap my ass and call me Judy, but I never heard of such a thing. Like a good metaphor, however, it makes sense as soon as I hear it: so many plant diseases are soil-borne that changing the soil balance would reasonably affect disease contraction, severity, and so on.

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Posted in Composting, Research Spin-off

Soil + sand = cement? Not so much.

October 17, 2008 by The Manic Gardener

They say adding sand to clay soil yields cement. Maybe sometimes. But based on a highly unscientific experiment in my back yard, not always.

The warning about sand pops up here and there all over the internet, often coming from university Extension offices. The one in Colorado for instance, says flat out, “Don't add sand to clay soil,” predicting a consequence that would make any gardener quake in her gardening boots: “this creates a soil structure similar to concrete.” A specialist with Ohio State University goes even further, saying that the result is usually “a disaster.”

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Posted in Research Spin-off, Soil & Amendments

Bindweed, garden enemy #1

September 2, 2008 by The Manic Gardener

This is the first of several posts on bindweed, scourge of the gardener’s life. I’m hoping to hear from plenty of people about methods and tactics. After all, it all started when a woman in the north-east corner of Montana sent me these pictures of her garden:

Those are bind-weed sprouts there against the bare ground and bindweed climbing the tomatoes. (I think those are tomatoes.) Now take a look at this one:

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Posted in Organic Gardening, Research Spin-off, Weed Control

Run! Run for your life! Kudzu is coming– (revised)

July 27, 2008 by The Manic Gardener

This is a revised (shortened) version of the original post, which included a long section from the lawn-care article mentioned below. For that article in its original context, click here for the weed page and scroll down for kudzu.

kudzu on the march– photo from the Coalition.

Research spin-off

The endless lawn article (Hey—how’d that work as a movie title? The Endless Lawn Article. You know, as a sequel to The Endless Story? No?) included a section on weeds, of course, and it occurred to me to wonder if the most famous weed of all, kudzu, was a problem in lawns. So I started googling away, and found things that made it hard to sleep at night.

I swear, kudzu is the stuff of nightmares and really bad science fiction movies, but it’s real. It’s a leguminous vine—yes, it’s cousin to your beans and peas, and brother to soy beans—but unlike any of those, it can grow several feet per week, enveloping entire trees, which it kills by depriving them of light and water. It looks most spectacular when draped over a thirty-foot-tall tree, but left unchecked, it will take over whatever is in its way, including, yes, your lawn.

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Posted in Research Spin-off, Weed Control

Ashes: Almost the Perfect Lawn Amendment

July 16, 2008 by The Manic Gardener

The Soil Series # 3

Having gone on at some length a while ago (twice!) about how wood ashes aren’t going to cause lead or mercury or cadmium poisoning if you use them in your garden, I am now prepared to tout them as the nearly-perfect lawn fertilizer. Since it seems that I’ve adopted this poor, misunderstood amendment as my own, I might as well do it thoroughly.

Grass needs calcium, which might be considered a non-renewable resource in a lawn: once the roots have used it up, it’s gone. So additions are necessary. The most common materials for such additions are gypsum, which contains about 22% calcium, and lime, at about 30%. The calcium content of ashes varies widely depending on type of wood, but even softwoods will produce ashes containing about 15% calcium, and hardwood ash may be as high as 50%.

A couple of things make ash a superior amendment, especially for lawns. For one thing, both gypsum and lime are quite insoluble. The term “immobile” seems an excellent metaphor for how they behave when applied to grass, but it’s also the technical term for a compound that doesn’t dissolve easily and therefore doesn’t move with water into and through soil. As a result, it is hard to get lime and gypsum into a plant: unless they’re snugged right up against the roots, they might as well be on Mars, for all the good they’ll do.

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Posted in Lawns & Grass, Research Spin-off