Composts
A term applied to any mixture of different soils or manures, either for potting purposes, or for top-dressing plants in pots or in the open ground. It may consist of different ingredients, with or without the addition of any manure, according to the habit or requirement of the subject for which it is intended. Manures that would prove destructive by their strength to any plant in a pot, may be mixed to form a certain proportion of the Compost, and thereby prove beneficial. Loam, in most cases, forms the greater bulk of soils used for fruit-trees, and for most strong-growing plants of the soft-wooded class. This is not often suitable for use wholly by itself, consequently the addition of other material has to be made, to render it lighter, and so encourage root action, or to keep it sufficiently porous to allow the free passage of air and water. Charcoal, sharp sand, leaf soil, burnt earth, peat, and many other things, besides so-called manures, may be used for this purpose; and, although it may be necessary to add something stronger for sustaining any given plant, yet one or more of these may be generally used beneficially. A Compost of any description should be thoroughly mixed before being used, in order that the different parts may be evenly incorporated. It should be in a condition not too dry nor sufficiently wet to cling together. This is very important, as the after condition of the plants will, in many cases, testify. All manures should be used when somewhat dry, and none applied when in a fresh state, as then they often prove destructive. Good leaf soil is one of the most useful ingredients for Composts, and that which has never been placed in sufficient bulk to cause violent heating, is the best. If obtained from woods where decay has taken place very gradually, it is much to be preferred. It should then be collected ready for use as required, and it will not, as a rule, generate sufficient heat afterwards to cause injury. Hard-wooded greenhouse plants succeed in peat and sand, and manure should never be applied to them. It must be remembered, in preparing a Compost for such subjects, that it will probably have to last for a period of at least twelve months. The following questions should be considered when preparing a mixture of soil. What is the description of plant for which it is intended? Is it a hard or soft-wooded subject and Is it to be potted temporarily or permanently? Young plants are, in all cases, benefited by having a lighter soil than others better established, as root action is thereby encouraged. These principles should always be considered, and all subjects treated accordingly. Suitable Composts for most plants are given under their respective headings; consequently, it is only necessary here to give instructions for general guidance. Study and personal experience with the various requirements of the plants to be potted, must be exercised in the application of suitable ingredients in the Compost. See also Manures.