Tomato plants planted in recently sown clover.

Cover Crops are an inexpensive convenient way of increasing Organic Matter in your soil. Some crops will also eliminate contaminates and fix Nitrogen into the Garden soil. They also smother weeds and prevent their germination during fallow times.

We all have down time in our gardens when it’s too hot or too cold to grow much, this is a perfect period to sow a Cover Crop to be turned back into the ground prior to the main growing season. Another practice in Organic/Biodynamic Gardening is to spell an area with a Cover Crop each year as part of a good rotation plan, generally every four years.

Listed below are some of the more common species ground to improve your Organic Garden Soil.

Legumes

This family all fix Nitrogen into the soil, they pull that Nitrogen out of the air through their leaves and then fix it via their roots onto the soil particles. So, in essence, they grow fertiliser for you, perfect, some also provide good bulk to be dug in for Organic matter. The most common are:

Lupins,

Excellent winter crop as they stand a reasonable frost, great for sandy soils as they don’t need much water either. My father-in-law swore by Lupins for his coastal garden, he grew them every winter. Cut them just as they flower and dig into the garden. Winter Crop.

Clovers,

Either White or Red, the results are similar, not as easy to get, you may need to visit an Agricultural Merchant to obtain seed. Doesn’t provide as much bulk as Lupins but can be left in place and planted through as they don’t get very high to compete with your vegetables. A lot of Commercial Farmers are now sowing a crop of Clover between their normal crops and then sowing the new crop through the Clover.  This will provide weed control and the Clover is continuously fixing Nitrogen in the soil. As it is only a small plant there is no completion for moisture. Winter Crop but doesn’t mind a mild Summer.

 Peas,

This group includes common Garden Peas, Chickpeas and Cowpea. I like this group as they will also provide a good source of food for the freezer if you can get them that far! Be wary with these if you have a wet winter as they are prone to fungal attack. Turn in after flowering or directly after picking the pods. Garden Pea is a Winter Crop, Chick and Cow pea will tolerate warmer climates.

Vetch,

A spreading plant that will choke out weeds and also encourages good Mycorrhizal activity in the soil. Adds plenty of bulk and doesn’t require a lot of moisture for its survival.  Winter Crop.

Soil Cleaner

Mustard,

A Brassica (Broccoli etc), Mustard removes chemical nasties from the soil. An excellent crop to rejuvenate a soil that has had years of conventional gardening to contend with. Let it grow to flowering and then mow and dig in. Used a lot in conventional market gardens when the soil gets extra “sick”. Winter Crop.

Bulk Plants

Corn,

A great crop to fill the freezer with winter vegetable while adding plenty of Organic matter. The roots add large amounts of material for soil improvement let alone the tops.  Needs to be processed before digging in, slash them down after picking the Corn and then mow the residue before digging in. Does need plenty of water. Summer crop.

Sunflower,

Not only a spectacular flowering plant but excellent at extracting Nutrients deep in the soil profile that your normal vegetables don’t get to. This nutrient is stored in the Sunflower plant tissue to be returned to the soil when it is worked in. As you can imagine the sheer volume of plant material available is enormous and will contribute a lot of Organic matter in one season. Needs plenty of water. Summer Crop. 

Grass

Rye,

Rye grasses be it annual or perennial have a “magic” effect on the soils Mycorrhizal activity. They can transform a tired overworked soil in one season, as with Clover can be left in place and just planted through. The Annual species can be left to die out naturally. Rye is good at smothering weeds and doesn’t need or use a lot of moisture. Another Cover Crop used in Commercial Cropping between main sowings, some graze the grass off with sheep prior to the new crop been sown. Winter crop.

Be Happy,

Barry.

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