How to fix compost: the compost not all is the same, it depends on the source material, and the difference essentially consists in the ratio between carbon (C) and nitrogen (N), that is the two most important chemical elements for plants, of the composted mass. Organic waste all have a different chemical composition and the result can only be one compost more or less carbonaceous or nitrogen based.
If you do not have the do-it-yourself chemist's kit for the analyzes (have the contents of the composter it seems excessive) you can get an idea of the composition of yours compost based on what it takes. Here, for example, are some 'ingredients' divided into the two families of 'nitrogenous' and 'carbonaceous' with (in brackets) the relative C / N ratio.
Organic waste rich in nitrogen: slurry (2-3: 1), chicken droppings or droppings (10: 1), grass clippings (12: 1), vegetable waste (13: 1), kitchen waste (23: 1), potato plants (25: 1), horse dung 25: 1), alder, ash and hornbeam leaves (25: 1), cow manure (30: 1).
Carbon-rich organic waste: leaves of lime, oak and birch, poplar, beech (40-60: 1), peat (30-50: 1), fruit (35: 1), coniferous (30-100: 1), barley / legume straw (40-50: 1), rye / wheat straw (100: 1), bark (100-130: 1), shrubs (100-150: 1), pure wood sawdust (100-500: 1).
Indicatively a good one compost usable as natural fertilizer it has a C / N ratio between 25: 1 and 30: 1 but your plants may also need other chemicals. In this case you can add additional substances (as well as natural bioactivators) to the mixture of composting. Here are for example which ones.
Different types of manure (they contain nitrogen but also potassium and phosphorus, as well as bacteria and fungi that help decomposition), horn flakes (nitrogen which is released slowly), blood meal (like horn but faster), d 'meal bones (phosphorus and calcium), wood ash (potassium), calcareous algae meal (calcium, trace elements, silica), rock flour (silica, calcium and trace elements, it is also a bioactivator and promotes the formation of stable humus), flour clay (absorbs moisture and odors, promotes the ability to store nutrients).
Do you need a large composter? Here (available online with home delivery) a 600-liter composter ready for use
If you buy the composter I also recommend the composter base
You may also need a (generous) package of compost bioactivator