By the end of autumn, summer's crops have been harvested and stored, the dead plants removed and the soil is left fallow. Good planning late summer and autumn will have winter crops planted whenever a patch of garden becomes empty. For example, leeks, Brussels sprouts, silver beet, kale, broccoli, cabbage, cauliflower, turnips, beetroot, parsnips and carrots can all be planted then for harvesting for winter meals.
Any empty areas of garden should be dug over, removing all traces of weeds and their roots. It is better to do this in autumn before the soil becomes cold and wet in the winter. Digging sodden soil is very bad for the structure, besides which it’s simply not fun to be out there digging in the depths of winter.
Nature doesn’t like bare soil and will attempt to fill the garden with weeds if left for long enough. For areas not planted in winter crops, there are various ways to keep your garden relatively weed free over the winter. You can spread a thick layer of compost or manure – the deeper the better. During the winter the earthworms will do a lot of the work pulling it into the earth to improve the quality of your soil.
Alternatively, you could plant a ‘green manure’ crop which will crowd out any weeds and then enrich the soil when you dig it back into the garden. Unlike most garden crops, a green manure crop provides all of it’s resources back to the soil.
Green manures work by drawing goodness out of the soil and storing it in the plant’s cells and root nodules. When the plants are then dug back into the soil they rot down and gradually release these nutrients to the next crop in a more readily-available form. Regular use of green manures improves the soil structure, breaking down hard soils and adding organic matter to light soils.
A green manure crop can be grown on empty ground at any point during a growing season. The fast growth and quick turnaround also makes a green manure crop perfect for planting and recharging your entire garden space in the early spring. Depending on the crop selected, the entire process can go from seed to "soil" in as little as 4 to 6 weeks.
Cover crops or ‘green manure’ crops, such as lupin, mustard, clover, oats, lucerne, broadbeans and buckwheat are grown from seed. They are fast growing and add value to the garden in a number of ways:
It is very important not to allow your cover crop to set seed or it will become a weed in your garden.
Blue lupin about to flower - dig this crop in now!
Mustard seed and young seedlings
Mustard mature enough to be dug in
Digging in cover crop oats