Compost
Compost
MAKING COMPOSTYou can liken making compost to making a stir-fry - you need a balance of as many ingredients as possible, and all of the finest quality. Too many beansprouts and it's boring. It is the same with compost; there must be a blend of lots of ingredients, preferably chopped into small pieces.
Large pieces of material have a small surface area compared to their volume so will take a long tome for the bacteria and fungi to attack them. In a stir-fry we chop all the pieces the same size so they cook quickly and evenly. Just as a hot wok will kill germs in a stir-fry, heat generated in a compost heap should kill weed seeds and diseases, but only if the compost is decomposing correctly. It is the bacteria in the heap that create the heat, and to thrive they need air (oxygen), moisture and nitrogen.
The most important balance to achieve is the proportion of woody (high carbon) material to sappy (high nitrogen) plants. Woody material, full of complex carbohydrates is like roughage in the compost heap. It keeps the compost open and aerated, preventing the soggy mass that results when you compost just nitrogen-rich material (such as grass cuttings). However, it has virtually no nutrients for the bacteria. Soft material contains the nitrogen bacteria need, plus water.
In winter, many gardeners fill a trench with uncomposted material in which to grow beans. This provides organic matter but it also encourages and feeds soil-dwelling slugs. While better than nothing, it's not good for clay soils with large slug populations.
ACTIVATORS
There are many types of activator but the most important role of most is to add nitrogen to the heap, which stimulates bacterial activity. Organic sources are best because these encourage fungal growth too. Most are sprinkled onto the heap as it is filled. Animal manure and urine are good activators (do not add cat, dog or human faeces) and you can add soil to introduce bacteria. Some activators also contain bacteria and fungi and these inoculate the heap to help get the decomposition started. You can buy brand name activators such as Garotta but we recommend Sulphate of Ammonia at £1.40 for 3kg which does the same job for a fraction of the cost.
GRASS CUTTINGS
Rather than taking them down the tip, use them in your garden. On their own, grass cuttings do not decompose well unless you use a special activator such as Biotal for grass, instead, mix them with dry waste on the compost heap or use them as a mulch on the garden in a layer about 5cm thick. In autumn, when clearing up, you can add the dried grass to the compost heap. Do not use grass cuttings as a mulch if the lawn has recently been treated with a herbicide or if the lawn is infested with weeds - the seeds will germinate in your flower beds.
SHREDDERS
A shredder is invaluable in a large garden where branches and woody stems are regularly removed from plants. Once shredded into small pieces they can be added to the compost heap as a source of woody material or mixed with manure to speed up its decomposition and make a valuable material for mulching around shrubs and to improve the soil.
No shredder- For twigs and thin woody stems just lay them on your lawn and mow over them with your rotary mower, it will chop them small enough for composting.
FULL OF LIFE
A rapidly decomposing compost heap will be too hot in the centre for many worms or other creatures but as it cools, and around the edges, you will find worms. At the drier, cooler edges, you will find woodlice and millipedes, which will be feeding on the dead plant material. If the heap is too dry ants may also make their nest - turn and water the heap to dissuade them. Occasionally slow-worms, grass snakes or hedgehogs make their hoes in unkempt heaps. These are not dangerous or harmful and should not be discouraged.
Wormeries can be kept in a shed or outbuilding, in a temperature of 12 - 25C. Kitchen waste is regularly added in small quantities. The resulting material can be added to potting compost and a concentrated, liquid plant food is collected from the base. Most kits are supplied with worms, starter feed and a source of calcium for the worms. You need to start with about 1000 worms.
LEAFMOULD
Every autumn, great fragrant plumes of smoke can be seen in gardens around the land as autumn leaves are burned. What a waste! Leaves are not a problem, they are part of nature's bounty and potentially the best soil conditioner available. Small amounts can be added to the compost heap or you can make leafmould.
Leafmould is wonderful stuff and, if well composted, can be used in potting composts. It is fibrous and looks similar to moss peat but has the advantage of containing plant nutrients. The best leafmould is made from leaves that contain the most lignin (woody tissue) and beech and oak are traditional favourites. However, these also take the longest time to produce a usable product. Softer leaves such as sycamore and horse chestnut decompose rapidly but result in a wetter product. But do not reject any leaves - even pine needles, which take years to decompose on their own, are useful in leafmould.
Fallen leaves in autumn contain little nitrogen and it helps to add extra. A convenient way is to mix grass cuttings with the leaves - easy if you have picked up the leaves when mowing. Or add organic nitrogen such as blood, fish and bone.
You do not need an elaborate bin to make leafmould; any compost bin will do but larger sizes are best to build up heat. Chicken wire cages fixed to stakes are ideal. Keep treading the leaves, water well and put a plastic cover over the top to keep out excess winter rain. You can use the leafmould as a garden mulch by the following spring or as a potting compost additive in about 18 months.
TROUBLE SHOOTING
If you tip out your compost heap and it?s a slimy, smelly mess, you did not add enough woody material. Mix in some straw or dried leaves and put it back in the heap for six months. If the heap has hardly changed at all it has been too dry and did not have enough nitrogen. Add some manure, if you can get it, an activator, some sappy weeds or grass cuttings and keep the heap moist.
COMPOST MYTHS
A compost heap will attract vermin and flies.
If you avoid adding cooked material and meat, your heap will not attract rats or foxes. In summer, kitchen waste will often attract fruit flies but these pose no health hazard.
A compost heap smells.
Provided that you do not add large quantities of grass cuttings a compost heap does not smell.
Compost heaps take up too much space.
Every garden has a shady place where it is difficult to grow plants. This is the ideal place for a compost heap and wooden compost bins are not unattractive.
Compost bins are too expensive.
You do not need to buy an expensive bin - you can make an efficient bin out of old pallets or other cheap timber. Within a year it will have produce the equivalent of many bags of soil conditioner for little cost and will continue to do so for many years, without the environmental costs of transporting bulky matter in your car or having it delivered.
You cannot compost rhubarb leaves.
Although rhubarb leaves are poisonous to humans (because of the high levels of oxalic acid) they are not dangerous to other plants and can be added to the compost heap, as can shredded hedge prunings of privet and conifers. For the best results mix them up with other types of materiel. Back to top