Organic Ways to Amend Your Garden Soil Structure

Fall and winter are great times of the year to begin improving your garden soil’s structure, enriching with organic matter and boosting the soil’s nutrients after having produced the year’s vegetation and in preparation to next year’s growth.

Plant Cover Crops

For some unknown reason, I’d say most gardeners don’t grow cover crops! This is a big mistake; perhaps they just aren’t aware of the benefits of doing so. They add great organic matter to your soil and help choke out weeds.

What are cover crops? They are crops grown for the purpose of improving your soil. Sometimes they are called green manures, most cover crops are grown for a few weeks, then turned under into the soil before they bear seeds. They directly add a crop of organic matter to the soil. It’s like composting on the spot.

Leguminous covers, such as vetch or clover, have root nodules that help fix nitrogen and so provide extra nitrogen for the next crop grown in that spot. It’s encouraged to inoculate legume seeds with the appropriate rhizoidal bacteria before you plant it to help its nitrogen-fixing capacity. Just ask the person who sold you the seed what powder to use and shake the seed in a bag with the powder before planting.

Crops like buckwheat or annual rye that are fast growing and thick as well can beat out or smother weeds. Who doesn’t want fewer weed problems next year? To rid a flower or vegetable bed of that quack grass, plant the area heavily in annual rye as soon as the soil can be worked in the spring. When the last frost date comes, mow down the rye, till in its roots, and plant a thick patch of buckwheat in the same spot. Once a month turn the buckwheat under, and plant more. Then in fall plant winter rye seed. By the following spring your garden plot should be cleansed of persistent weed troubles!

Cover crops can also be used to over winter parts of your garden that otherwise would be bare and vulnerable to erosion for months on end. Winter rye, for instance, will start growing in the autumn and, in most areas, survive winter. Then they have a new spurt of growth in the spring. Try growing annual rye in the fall. In your area it may winterkill and make great mulch for next spring’s planting. Try also combining either rye with a hardy vetch, hairy vetch is most popular, which adds nitrogen to the soil and seems to have other benefits, as well. A hot new idea among tomato growers these days is sticking their tomato plants in a chopped-down but not turned-under bed of over wintered hairy vetch.

All of these uses are in addition to the old, main reason for growing cover crops: to add green matter to the soil.

Mulch

Mulch, along with its weed-smothering, water-retaining, and soil-cooling virtues, provides an ongoing supply of rich organic matter as the soil beneath it as it breaks down. It’s a very successful way to build up soil but, well, it is kind of slow. In addition, fresh mulch (such as fresh sawdust) consumes nitrogen in its first breakdown stages, so green mulch can temporarily absorb that nutrient.

Adding a mulch cover is a fine way to improve the organic matter content of your soil. After all, there are those deep-mulchers who maintain perfectly good gardens by doing nothing more than continually piling on more and more mulch!

Some gardeners believe in keeping one third to one half of your garden in a cover crop at any one time. Or allowing a full year’s time dedicated to cover crops and then rotating your actual garden area the following year into the rich organic and rested soil. Then planting cover crops the following year to the area just used.

Your goals don’t have to be huge and elaborate. But, for certain work cover crops into your crop rotation scheme. That way, you’ll be rotating not three elements, but four: root, leaf, fruit, and cover crops. Along with that plant cover crops any other chance you get.

Cover crops are easy to grow. Just work up the soil enough so you can plant (you don’t need to make it super smooth). Broadcast the seed, sowing thickly by hand, first in one direction and then perpendicular to it. Then lightly rake over the area to cover the seed.

I can’t begin to cover all the cover crops available, so I’ll just mention the most popular ones:

Buckwheat

This weed-smothering crop grows so fast you won’t believe it and makes a little grassy field topped by lovely, small white flowers. Very easy to turn under. Only grows in warm weather. Not a nitrogen fixer, but great for adding green matter.

Clover

Clovers are as easy to turn under as buckwheat and have the added advantage of adding Nitrogen to the soil. White or red are popular varieties, and seeds are readily available.

Hairy Vetch

A delicate legume with purple flowers, hairy vetch is quite cold hardy. It can be a little hard to get a thick stand of it, so it’s often grown with a rye (especially winter rye) to provide fuller soil cover and give the vetch support.

Rye

Annual for spring, winter for over wintering it provides great volume of tall, grassy growth. Winter rye can be mowed as needed the following spring to keep it under control until you’re ready to turn it under. Try to turn it under in early spring however as the roots can be difficult to do so if you let it remain until later spring.

Soybean

This is another nitrogen fixer, one that provides a good leafy soil cover. Turn it under before it flowers or most of the nitrogen value will go into the seeds.

How do you turn them under? It can be pretty hard to do by hand. If possible, I like to mow my cover crop down; it chops the plants into small pieces that turn under easily and decompose rapidly and till the cuttings and roots under with a rototiller. If the crop’s too big to mow, you can cut it with a weed eater, or swing blade. Then rake the cuttings off to a compost bin (thus add to the soil later), and turn under the roots.

Don’t plant vegetables or flowers in a cover-cropped area until at least three weeks after you turn the cover crop under. It takes that long for the green matter to begin to break down.