Many old time farmers and backyard gardeners seem to have found the secret to growing produce successfully, year after year.
We, on the other hand may have a bumper crop for one, two, maybe even three years in a row and then run into problems that produce only stunted, unhappy plants.
Sound familiar? Take heart, this is a common problem that can easily be fixed once you understand why this happens.
Vegetable plants are very heavy feeders and consume high levels of nutrients during their short growing period. As a result, vegetable plants leave the soil tired and depleted of fertility.
A lack of soil fertility will result in slow growth and plants that can appear stunted.
Insufficient nutrients can also leave plants more vulnerable to pests and disease, because there are not enough reserves to fight off the attack. Just like us, when we haven’t been eating a balanced diet, plants can get sick due to a lack of vitamins and minerals.
In the same way that we regularly feed our bodies, we also need to regularly feed our plants.
Plants are fed by drawing up nutrients through their vascular system from the roots. The roots draw nutrients present in the soil moisture and an effective natural method to feed the soil is with a green manure.
Green manure is a crop that is grown for the purpose of reinvigorating tired soil, adding nutrients and bulky organic material to the soil. Green manure is grown for a short time, usually only about six to eight weeks.
While the crop is still soft and sappy, it is slashed at ground level and dug back into the soil where it was grown. Because the growth is young, it is still fleshy, and full of nitrogen, which provides the next crop with the elements required for good strong leaf and shoot growth.
Any crop can be grown and dug back into the soil, but some plants are especially good for certain things. A legume is grown for adding nitrogen to the soil and lucerne, peas, clover and lupins are used for this purpose.
A cereal or grain crop like wheat, buckwheat, oats or rye can be grown to add bulk organic material and provide a range of minerals. After it breaks down, the remaining humus helps improve the soil structure by opening up heavy clods in clay soil allowing better drainage and easier root development.
These two types of plants can be sown together with a fumigant plant as well, such as mustard, fenugreek and marigolds, which are often used as green manures and dug into the soil to repel nematodes and other soil borne diseases. Microorganisms feeding on the extra organic material can work as good bacteria in breaking down pathogens.
The best time grow your green manure is during the cooler months, several weeks before you plan to plant your next season’s crops. Choose a suitable variety of legume, cereal and fumigant for your area and then broadcast the seed over the proposed garden bed.
Firm the seed into the soil and water it gently. Keep the area moist until the seed has germinated. The garden bed should be sown heavily, more densely than you would normally grow plants together, since it will only grow for a short time.
Grow the plants until the crop reaches about knee height. Then, simply slash it all and dig it in. Leave it to rot down for a couple of weeks and the soil will be ready for planting your next crop. Your soil will then be rich and full of life once again.
Toni Salter, ‘The Veggie Lady’, is an Australian registered horticulturist living in Sydney. Follow Toni on Twitter and ‘Like’ her on Facebook.
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