News From The Allotment: March 2018

March 03 2018

HARDLY a month goes by in this column without the mention of compost and there’s good reason for this, it is after all, the lifeblood of any plot. But even so, to some our headline may seem bizarre.

Growing crops for compost?

HARDLY  a month goes by in this column without the mention of compost and there’s good reason for this, it is after all, the lifeblood of any plot. But even so, to some our headline may seem bizarre.

Compost bins on some plots are there merely too be filled with plants that have reached the end of their useful life, so actually growing plants simply to help fill these containers may seem a little strange at first. There’s good reason for this – but which plants would you use for the purpose? For example, who would really want to take their favourite bedding plants in their prime or beautiful vegetables and deposit them on the heap? The answer is something which is relatively quick and inexpensive to grow, put simply, Green Manures.

Green Manures come in a wide variation and all offer a win-win solution for many problems; the list is actually quite extensive and diverse in their objectives in life. But without doubt all are excellent multi-taskers, some add nitrogen to the soil; others help break up heavy clay, the resulting foliage of all varieties can be dug-in to the soil which adds humus, or cut and chopped as an excellent addition to the compost bin. And if that was not enough, should you have an area of your plot that is expected to be dormant for several weeks, a cover of green manures will supress weeds and protect the soil from erosion whilst gaining the soil improvements just mentioned.

The only perceivable downside of green manuring is that the dense carpet of green that will be produced makes a perfect environment for slugs and snails. Nevertheless, if specifically required for composting, the foliage if cut young will bulk out the contents of your compost heap and quickly rot down. This green matter will rapidly generate heat at the start of the decomposing process, but once cooled tiny red brandling worms which have been described as ‘the intestines of compost’ will move in and spend their days munching through half their body weight of the dead organic matter, which is deposited out the other end as worm castings – a refined, nutrient rich material that when added to soil will both condition and fertilise.

Taking this process a step further, one of our plot holders, who’s asked to remain anonymous but for now we’ll call him Ern, has recently planted an area on his plot with Mustard and Buckwheat green manures specifically for the thick foliage alone that these plants will produce over the coming weeks. The main reason being is that he has created a temporary compost bin as a bed for growing giant pumpkins and he needs to fill it as quickly as possible with nutrient rich material. Hopefully, Ern says the contents of the bin which will contain a mixture of other waste items such as old grass cuttings, straw, spent hops, leaves, coffee grounds, brown cardboard and all peelings from the kitchen will feed the ravenous plants throughout the summer to produce some handsome specimens (watch this space) for our Pumpkin Show at the end of October.

The containment of worms has yet another useful addition to the plot by adding a ‘wormery’. This produces small amounts of rich composted material but is mainly used for the worm wee that is collected as a by-product. Commercially produced worm homes are available but it is relatively easy to make one. Simply, these consist of three plastic boxes, ones that do not let light through and will nest inside each other to form a tower. Cut out the bottoms of the boxes and replace with strong one inch wire mesh, securing it with cable ties.

The tower needs to be supported over bricks so a tray, about 3 inches deep can slide underneath to collect the liquid. But before so doing add a further piece of wire mesh slightly larger than the base of the boxes to form a bridge, add a perforated plastic sheet immediately on top of this mesh and under the first box, this will stop worms dropping through and drowning in the liquid. Cut the plastic sheet larger than the tray to stop rain entering.  The first box is then half-filled with damp compostable material such as general kitchen waste (no cooked food) is fine. Add to this as many as possible of bright red brandling worms, you’ll find these in an existing compost heap, but not the fatter earth worms. Add another layer of material to cover the worms, then half-fill the other two boxes with scraps, place inside each other to form a tower. Add a lid to keep out rain but do not make it air tight. The worms immediately get to work consuming and recycling the organic matter in the first box.

Once food becomes scarce in the bottom level the worms will naturally gravitate upwards to the next box through the mesh leaving a box of worm castings behind, which can then be emptied onto your plot as excellent compost. The worms having moved up to box number two can now become the lowest box, the empty box is re-filled with scraps and is replaced on top of the tower. And so the cycle goes on, the worms will rapidly re-produce and happily continue life in the tower, but by regularly rotating the boxes they never reach the top! The tray will collect highly charged liquid compost that when emptied will need to be diluted 20 to 1, better than any liquid fertilizer you can buy.

We have produced a leaflet if you would like to learn more about green manuring or if you need help building a wormery please get in touch with us.


Bristol East 

Allotments  Association.

Nicholas Lane

St. George

BS5 8TY.


Email: or call 0117-932-5852.