24 " " 7-1/2 16 " " 8-1/2 12 " " 9-1/2 8 " " 11 6 " " 12-1/2 4 " " 14 2 " " 15-1/2 1 " " 18

==Watering== is sometimes conducted on the principle that the usual time has arrived, and therefore the plants must have water.  But do they need it?  Press the fingers firmly on the surface; if particles of soil adhere it is too dry.  Or tap the pots smartly with the knuckles or with a stick, when a clear and unmistakable answer will be obtained.  Plants differ widely in their demand for water.  Some are very thirsty, others require less frequent attention.  The season of the year and the state of the atmosphere have also to be considered, as well as the fact that a heavy soil is more retentive of moisture than a lighter compost.  A watchful eye and a willing hand will seldom err on this point.  The water should always be of the same temperature as the house, otherwise the plants will be constantly checked.  A tank in the greenhouse meets this requirement.  In its absence, the watering-pots should be kept full under the stage, and they will be ready when wanted.

In the open ground, it is better to water a few plots thoroughly for two or three successive evenings, and then have an interval, rather than moisten the surface daily.  The effect of constantly applying small quantities of water is to encourage the surface growth of roots.  Then, if the sun shines fiercely on the soil, the first day of neglect results in immense mischief.

==Drainage== is easily managed.  Into each pot put a crock almost the size of the bottom, with the convex side upwards.  There need be no niggling to remove sharp angles, or to make the fragment shapely.  Cover this with smaller crocks, and these with moss, or in some cases with small pieces of charcoal.  If the compost has a proper admixture of sharp sand or grit, free drainage will be insured, and yet the soil cannot be washed through the pot.  Silver sand is often employed, and there is nothing better for the purpose.  But the sweepings from gravel walks, finely sifted, may be substituted.  Road grit is often infested with weed seeds.

==Ventilation== is important, for a house full of plants cannot long be kept closed with impunity.  The lights should be opened whenever the state of the weather may permit, and by doing this on the side opposite to the quarter whence the wind blows it is frequently safe to give air when it may be dangerous from other points of the compass; and it should be done early in the day, before the sun gets hot.  Often the lights remain closed on a sunny morning until the atmosphere becomes stifling; and then perhaps plants which have been made sensitive by excess of heat are subjected to a killing draught.