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Last week I encouraged you to replace your summer crops with Asian greens and to start thinking about putting in winter vegetables such as cabbages and cauliflowers. Well if you're not up for another season of gardening, or if you're heading up north for some warmer weather, green manure is a great way to give your soil a boost with a minimal of effort and no maintenance.
The idea of a green manure crop is that you sow seeds in an empty (or fallow) garden bed and simply just let the plants grow. But rather than obtaining any kind of harvest, you simply dig the mature plants back into the soil!
Now bare with me because I know this sounds like a kind of pointless exercise, I mean why grow something when you just dig it up again? The thing is when it comes to growing food organically, our focus tends to be on the soil rather than just the plant. So by planting out a green manure crop we're really just 'feeding the soil' and making sure it's in the best shape to deliver nutrition to our veggies.
By digging in your green manure it will add fertility, aid with soil structure and encourage earth worms to pay your garden bed a visit. Plus with all that organic matter now in your soil, your revitalised veggie patch will be much better at holding water.
So what can you plant as 'green manure'? An old favourite is Lucerne - probably better known as alfa alfa. Yes believe it or not those little sprouts that polarise culinary tastes in sandwich bars world-wide are the same seeds that grow into the most popular feed for horses and cattle on the planet. Belonging to the legume family, lucerne will enrich the soil with nitrogen, but any other unwanted pea or bean seeds will also do the same.
Perhaps a more accessible seed to use is simply a mixed bird grain which you'll find at any supermarket or pet food supplier. For the beds I'm I've been using the grain mix I feed my chickens, plus adding any old pea and bean seeds that I've stumbled across so I get the advantage of nitrogen 'fixing' to the soil. Just make sure you don't accidentally sow a nice bed of kikuyu or other running grass or you'll forever be stuck with it in your veggie patch!
Of course one of the other advantages of having something growing in a otherwise empty bed is that you'll be less likely to suffer weed invasions. Green manure crops can be planted very densely and grow vigorously making it a difficult for unwanted seeds to germinate.
So to give your vegetable beds the equivalent of long service leave, try planting a green manure crop this weekend and reap the rewards come spring time!