WE all know that better soil equals healthier plants. For many that means laying down a thick covering of well-rotted manure at the end of the season. However there is an alternative.
Green manures offer a simple, cheap way to fertilise your plot. They boost soil structure by preventing erosion and improving drainage, and increase fertility by helping return nutrients to the ground when they’re dug in, covered and left to break down over the winter.
The range of green manure crops is too extensive to cover here, see for yourself, but we’ve picked a few options to get you started:
Summer Quick Fix Mix
A blend of seeds (including mustard and several types of clover) best sown between May and July, Summer Quick Fix Mix is excellent for building up nitrogen levels in your soil. As the name suggests, it’s a fast-growing variety, meaning it can be dug into the soil after just 10 weeks. Just make sure you don’t allow it to seed.
Yellow Trefoil & White Clover
A slower growing mixture that can be sown from mid-March onwards, Yellow Trefoil & White Clover are an excellent weed suppressor and a magnet for bees and other insects if left to flower.
Good for fixing nitrogen and improving soil structure it can also be undersown – sown in a patch where, for example, brassicas or beans are already well established.
A short-term, fast-growing summer option, Buckwheat is best sown between April and June. An excellent weed suppressor, its long tap roots mean it’s good at scavenging phosphate from deep in the soil.
Rye/Vetch Over-Winter Mix
No single species of green manure can provide everything your soil needs, so growing a nitrogen lifter and a fixer together is an excellent way to improve your patch. This rye and vetch mix can be sown through September and October and dug into the soil between February and April.
Quick growing and able to germinate at low temperatures it’s no wonder phacelia is the pick of green manure for a large number of allotment holders. An excellent weed suppressor its extensive roots also mean it’s superb for improving soil structure and is a good nitrogen lifter. A favourite of insects thanks to its high nectar output, Phacelia can be sown from May to mid-September and dug in within six weeks of sowing.
Note: Phacelia is currently available at the St Julians Allotment on-site shop