Garden compost | Leaf mould | Potting compost |
All sorts of plant material can go on the compost heap
Good hygiene – clearing away old crops and weeds – is an important preventative measure against pests, diseases and weeds. In addition, there is always a lot of grass clippings, and foliage from hedge-trimming and pruning – not to mention fallen leaves! The best way of disposing of this material, turning it into a valuable asset – garden compost – is to set up a compost heap.
Simply stack up a 25 centimetre layer of plant waste in an out-of-the-way corner. Scatter a handful of general fertiliser over it, if desired, and put on a 5 centimetre layer of soil. Start another layer of plant material and repeat the procedure until the heap is about 90 centimetres high, and 150 centimetres square.
Timber or galvanised sheeting can be used to retain the sides of the heap. Turning the heap speeds up the process. The compost is best left for a year or so, but can be used after six months if sufficiently decomposed.
Leaf mould for use as an ingredient of potting compost – a peat substitute – can be made by gathering leaves in autumn and placing them in a separate heap made in the same way as described for a compost heap. Place and old carpet on top to keep moisture in and maintain a little downward pressure on the heap. Do not add soil or any other material.
The leaves will rot down and can be turned after one year. They may need to be watered in dry weather. After a second year, the leaf mould will be dark and crumbly and it can be run through a shredder to break it down and make it finer.
Home-made potting composts can be quite satisfactory. They are made from soil, peat or leaf mould, and sand in the ratio 7:3:2 by volume. The soil should be good quality garden soil, sieved to remove big stones.
For seed compost, the soil can be sterilised by cooking in an old saucepan, or such like, for about half an hour, but this is not necessary for potting compost, and it is not even desirable because it destroys useful soil predators and parasites that offer a good level of protection against vine weevil larvae.
The steam generated by heating the soil kills pests, diseases and weeds. After about half an hour of good steam, allow the soil to cool and then mix it with the new peat and sand. The latter should be clean horticultural sand, and if not, sterilise it too. Do not use sea sand.
Into the mix, put John Innes Base Fertiliser at the rate specified on the pack. This varies depending on how rich a compost is to be prepared. Compost for seedlings and small plants need not be rich – older plants need more food. Lime will need to be added if the soil used is acidic.