Retarding requires as much skill as forcing, for as the latter requires the application of all that is suitable to the promotion of a plant's rapid healthy growth, so retarding requires the withholding from it of those contingencies. Thus to retard growth, the lowest temperature, and the least degree of light compatible with healthy growth must be secured; and to this end plants for succession are often placed on the north side of a wall.

Then again, as in the case of raspberries and strawberries, plants are often cutdown in the spring, compelling them to form fresh foliage and stems, and thus be productive in the autumn instead of the summer.

The vegetation of many bulbs may be prevented by merely keeping them dry, and, indeed, the withholding the usual supply of water, giving it only in diminished quantities, is necessary in all retarding treatment. To secure the entire quiescence of bulbs, and of such plants as will bear so low a temperature, the atmosphere of the ice-house is effectual; and to this end it should have a few shelves for the support of boxes or flower pots. Banks of earth ranging east and west, and facing the north at a very acute angle, are very useful in retarding the early advance to seed in hot weather, of spinach, lettuces, etc. Espaliers ranging similarly, and shaded during the whole of March, and the two following months, will blossom later and more unfailingly than trees more exposed to the sun in spring. Similar exclusion of heat and light retards the ripening of picked fruit, and if the air be excluded from them, or its oxygen withdrawn, fruit will remain unripened for weeks. To effect this, put a paste formed of lime, sulphate of iron, and water, at the bottom of a wide-mouthed glass bottle, then a layer of large pebbles to keep the fruit from the paste, - then fill the bottle with peaches, apricots, or plums, gathered a few days before they are ripe, cork the bottle tight, and cover the cork with melted resin.

They have been thus kept for a month, and summer apples and pears for three months. They ripen when again exposed to the air.