This time of year is the time to prepare your soil. Soil needs feeding just like plants do. When you grow anything in the ground you take goodness from the soil, and vegetables take quite a lot of it. Whatever you eat is taken from the soil and the goodness leaves with it. Hence you must put goodness back. Organic growers feed the soil so that the soil can feed the plants
Well rotted manure is a good idea. Manure comes in various kinds. Horse manure comes from stables and often contains weed seeds, but it is still good. Cow manure is taken from barns where cows are kept. Ideally manure should be well rotted before you apply it, as otherwise it might burn the plants as it rots down. Pig manure is very strong and not the best for gardens. Chicken and other poultry manure is fine, but it is very strong and should be applied sparingly. It is not a bad idea to add it to the compost heap, as this will enrich the soil but will be distributed throughout the compost. Manure often comes in pellets supplied in tubs and bags. This is an easy way to cart it around, but while it still contains nutrients, it does not supply much bulk to the soil and lacks the water found in unpelleted manure. Apply manure as a mulch over the ground and around the roots of trees.
Compost, which is the decayed remains of plants, comes in various kinds, and there are different kinds of compost for different tasks. For generally preparing your ground a general purpose is good. However, there are some loam based composts still available. These contain more soil and are quite beneficial. They are derived from composted turf.Garden compost is the remains of garden plants allowed to compost down in a bin or compost heap. However kitchen compost is very useful, as it contains remains of foods, which are quite nutrient rich. I keep my kitchen compost in a large bin, but have compost heaps for the allotment compost, the plant remains. Tea bags and banana skins are good components of kitchen compost, as they are rich in potassium, which is an essential soil nutrient. Meat should never be added to a compost bin, as it attracts rats.Nettles are a useful addition to your compost heap, as they draw up minerals from the subsoil, which can then enrich the surface layers.
Worm compost is a kind of manure. It is produced in a wormery, also known as a worm bin. It is very strong and should be applied sparingly across the plot. However, the juice form a wormery, which is drawn out by tap, is extremely nourishing for plants [foul smelling, though.] This is very strong and should be applied by diluting it in a watering can.
Mushroom compost is left over from mushroom production. It is a useful soil supplement and can supply much needed calcium.
Seaweed is an important source of nutrients. It can be applied directly, if you live near the sea, but the rest of us have to purchase it as seaweed meal or in liquid form. I like to apply it to all my crops, as it supplies essential trace elements. It is not unduly salty.
Well rotted leaf mould can add some goodness to the soil. This is made from piles of leaves that have been allowed to rot over a year or two. It does not add a great deal of nourishment, but it does enrich the soil structure. It is of course possible to mulch [cover] the ground with leaves and leave them to rot down. This will supply nourishment as the leaves rot and also help to suppress smaller weeds.
A recently introduced soil enricher has been rock dust. Soils contain minerals derived from rock, and these are an essential component of soil health. In recent years there has been a growing awareness that soils are becoming demineralised through mineral loss from agriculture and horticulture. But it is possible to find granite dust obtained from grinding granite in quarries. Other kinds of rock might also be used in future, if they are suitable. Supplies can be found on the Internet if you type rockdust into your search engine.Clay also helps to mineralise soil, as clay soils are extremely fertile, if hard to work. Clay can be dug in, but it is not easy to obtain.