A perfect time for a green manure

With the harvest of your vegetable crops well under way, there will start to be spaces appearing in the vegetable patch. There are several options to how you manage your beds over the winter, including the covering of them with mulches after digging in organic matter to replenish your soils nutrient.

This includes organic mulches such as newspaper or straw which break down over the winter, provide carbon, prevent soil erosion and keep the weeds away. Less favoured for myself is the use of black plastic or mypex, however they also prevent nutrients being washed away. The key thing is ensure you have it secured firmly otherwise you could be hunting down your cover after every stormy night.

A great alternative is the living mulch or green manure. A green manure protects your soil from erosion and adds organic matter to the soil when it is tilled (turned into the soil) so next spring your vegetable garden is ready for planting.

Winter Tares
Winter Tares is a hardy annual that can be sown March-May or July-September for over-wintering. It is good at nitrogen fixing and for weed suppression on heavier soils but avoid acid or dry soils and dig in before flowering.

Winter Tares green manure is part of the legume family so grow on ground with/after legumes in a crop rotation plan. Any harmful pests & diseases will show up in the green manure rather than the more valuable veg. It helps to fix nitrogen and once dug in will fertilise the following nitrogen hungry crops like brassicas.

Protect from slugs/snails and birds especially pigeons who like to nip the tops off. Winter Tares releases a chemical that inhibits the growth of small seeds (particularly carrots, parsnips & spinach) so a month should be left after digging it in before sowing the next crop. It does not pose a problem for transplants or young seedlings.

Grazing Rye
Forage Rye Green Manure (also known as Hungarian Grazing Rye) can be used anywhere in crop rotation plans and is one of the best for over wintering.

It’s an excellent nitrogen lifter and it can lift and release up to 90% of nitrate to the next crop. Rye has deep penetrative roots that help to break up heavy soils and so improve soil structure. It is brilliant at suppressing weeds as it grows quickly and continues to grow in cold conditions. It suits most soils and copes especially well with heavy clay ones. It does require the correct conditions to germinate in autumn (not too much rain) and watch out for slug/snails who like its tasty leaves and birds who like to nip off the tops!

It may be fairly hard to dig in after winter especially on heavy clay soils (good exercise though!) If it is difficult either loosen roots one day and then dig in a couple of days later, or cut down foliage and cover with a light excluding mulch such as black plastic for 3 weeks and it will then be easier to dig in. The foliage can also be added to your compost. Sow August to October and dig in during early spring.

Now is the perfect time to sow them to allow for germination and for essential growth before the ground temperatures drop. And as a pack of seeds come in at under €2 you can’t go wrong with a green manure and our advice comes free of charge.

4 thoughts on “A perfect time for a green manure”

  1. I want to use Alfalfa on my patch which can be quite wet, I have been told Alfalfa is a suitable green manure. Would you recommend it?

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