Lists of Compost Ingredients help you to choose materials that will be beneficial to your compost
The best compost comes from a variety of materials. Introduce as many different compost ingredients as you can.
Common sense will usually indicate what compost ingredients are suitable and what are not and as long as you take reasonable care, you will have few, if any problems. If you do make a mistake, your compost heap will tell you, usually by developing a not-so-lovely perfume!
On a day-to-day basis, the most common additions you will make to your heap will likely be kitchen waste and garden rubbish.
Compost Ingredients from Indoors
Organic waste from food preparation in the kitchen is all acceptable, as long as it is vegetable matter, NOT meat, fish or dairy. That means no egg yolks, (dry egg-shells, well crushed are OK) milk, butter, yoghurt, bones, skin or fat. There are two reasons for this:
- These products are slow to decay, smell bad and attract vermin to your pile. A plague of maggots, rats, or even the odd fox is not what we are about here.
- Because these compost ingredients take time to decay, there can be a build-up of the fat component which can block off the oxygen that your microbes need to do their work.
(Having said that, there are compost systems, for example Bokashi composting, which can be carried out in your kitchen, that can cope with these materials should you decide that you want to deal with them..)
So from the kitchen waste, we can use, among other things, fruit and vegetable peelings, dry egg-shells, tea bags, coffee grounds and filters. From the rest of the house, consider shredded newspaper and cardboard, rags made from natural fibres like cotton or wool, fluff from your vacuum cleaner, hair clippings, and pet fur. A sprinkling of ash from the wood-fire is fine, (coal is a no-no) but do not overdo it and mix it in well. Any vegetables or fruit that have started to decay would be welcome too.
DO NOT compost kitty litter, pet manure, human manure (do-able, but needs specialist knowledge and equipment) meat, dairy, oils or fats. Pet manure can contain pathogens that are harmful to humans.
Compost Ingredients from Outdoors
From the garden, our compost ingredients will include most of our garden waste (including grass) we accumulate when weeding and pruning. Grass/lawn clippings are good, although you may prefer not to collect them but to leave them as a mulch on the lawn itself. Should you decide to compost them, be sure not to just drop a vast quantity on the pile and leave it there. Grass clippings, when in a dense pile, heat up rapidly and start to rot. They quickly become anaerobic, smelling bad and, as with the fat from meat, blocking off the oxygen needed by the aerobic bacteria to do their task. Always toss grass clippings through your heap, roughly dispersing them and making sure that there are no big clumps. Leaves, both dry and fresh are fine, twigs and small branches – the fruits of pruning and some weeds are OK, too. Do not forget sawdust and fine wood chippings (not too much), hay and straw, manure from horses, (be wary of seeds from bedding straw and hay) cows and chickens, feathers and dead plants. An occasional shovel-full of top-soil is good, too, to keep things moving along.
When collecting your garden waste, DO NOT include diseased plants, those which have been sprayed with pesticides or herbicides, coal or charcoal, wood which has been treated with chemicals, or glossy magazines.
A special warning here! Avoid adding specimens that are carrying seeds or which grow vigorously from pieces of the stem or root (rhizome) like Agapanthus and do not add invasive weeds such as Morning Glory, or noxious weeds like Old Man’s Beard (in NZ). These will vary from country to country, depending on local conditions. In NZ, for example, Agapanthus grow like mad and spread everywhere. They are very difficult to control, once they get out of hand and are often referred to as “the rats of the plant world” . They are used on motorways (they do look great – heavenly blue, vibrant green and a matching blue sky) as they are so vigorous and need no care at all. In the UK, they are sold often to grow in pots. The colder conditions here are less than optimum and so the problem is not so acute. In any event, you need to be sure that your compost reaches a very high temperature to be confident that any seeds are killed. If this is not the case, you are just spreading trouble for you and for the environment at large.