THE GREENHOUSE FLOOR
Greenhouse flooring is a very important matter, since so many beginners seem to think that the floor is to be grown in. If the ground soil of a greenhouse is used there is invariably trouble. Today we recommend using only properly prepared composts in containers. The floor is therefore best only regarded as for walking on, or standing things on.
If a greenhouse border effect is wanted, a trough can be used to contain the compost. This can be sunk into the ground, the lining being thick polythene with a few holes or perforations for drainage, or the polythene can be draped over a frame of timber boards resting on the greenhouse floor. The depth of the trough or frame will depend on the plants being grown. Alternatively, such containers can be filled with peat and the plants in pots plunged in this.
A greenhouse floor can be of concrete or similar material. However, this often has the disadvantage that water can collect in puddles. It also holds little moisture over long periods, and this may be a disadvantage in summer because of its poor contribution to atmospheric humidity.
Generally it is simple and convenient to use the ground on which the greenhouse stands. This can be pressed firm and covered with shingle or gravel, of the type used for drives and paths, to give a clean, neat appearance. To make walking more comfortable, concrete paving slabs can be put down on top where required. A floor of this type will hold plenty of moisture and keep the greenhouse nicely humid in summer. In winter it should be allowed to dry out so as to keep the air more dry.
Any total weed killer can be watered into such a floor freely sodium chlorate or any of the proprietary path weed killers but plants must of course always be stood on plastic or paving so that their roots cannot enter the treated ground.