Allotment Secrets – Green Manuring

Green manuring is the big, but largely unknown, ace in the hole for the serious allotment gardener. Growing vegetables is an intensive business after all, and every vestige the goodness that goes into your lovely crops has to come from sun, water and … soil. So what you take out of the soil has to be replaced and the easiest way to do this is to use a green manure on parts of your plot that are not in current cultivation.

So, for example, let’s assume you had a lovely crop of winter veg and didn’t fill that area with summer plants – what you should do, to guarantee a rich and fertile soil, is sow a green manure and then dig it into the ground before it flowers so that it doesn’t become a weed and so that all the goodness of the crop goes into the earth. This does two things; it provides a small amount of nutrient that subsequent plants will be able to extract from the soil, but – more importantly – it increases the humus content of the soil which means that it can absorb plant foods more easily and has an improved structure which is easier to work and more retentive of water. Suitable green manures are mustard seed, annual lupins, rape, winter spinach or vetch, or many companies now sell a blend of green manure that you simply sprinkle on the soil and then dig in. These crops will all need a nitrogenous fertilizer (I use ammonium sulphate granules) at about 2 ounces a square yard sprinkled on the soil as you dig the crop in – this allows the bacteria in the soil to do their work of breaking down the crop. If, however, you plant a nitrogenous fixing green manure such as peas, beans or clover, the fertilizer isn’t necessary.

Now the thing you’ve got to bear in mind is that if you don’t get to your green manure in good time, it will flower and seed all over the place which will make you VERY unpopular with other allotment holders, so don’t plant a crop unless you’re absolutely sure you’ll be on hand to cut it down and dig it in.

Labels: allotment-crops, allotment-secrets, green-manure