Lime is the key to the soil. It is not so important to know in what form lime can be applied, for almost any form of lime will do, and the cheapest local supply is generally the best to buy. Finely ground lime is ideal, since it quickly mixes with and sweetens the soil. Ordinary slaked lime from the nearest builder’s yard is good, especially for heavy and acid soils. It should never be mixed with other fertilizers. Quicklime, when spread over vacant ground, is excellent, because it acts as an insecticide as well as a fertilizer.
As a rule a small application of lime annually—from two to four ounces per square yard—is better than a large dose every three years; but a neglected garden, where the soil has become sour, needs an extra large dose, and half a pound to the square yard can be given in such cases. The best time to apply lime is immediately after digging in the winter. Rains will gradually wash it down into the soil where it will do its work.
Chalk is a form of lime, and can be used with special advantage on sandy soils, where it assists in retaining moisture Chalk should be used at twice the rate of lime, and as it has no burning action, it can be used at any season, and hoed or forked into the soil.
Chalk is valueless as an insecticide, but for other purposes may be regarded as a substitute for lime.
Gas lime when fresh is an efficient insecticide for vacant ground; it should be used not later than November, at a rate of not more than four ounces to the square yard, if planting is intended the following spring.
A useful all-round mixed fertilizer can be made up of one part each of sulphate of ammonia and sulphate of potash, and three parts of superphosphate. It can also be made up into liquid form, with a pound of mixture to twelve gallons of water; apply at the rate of about three gallons to a square yard.