Beds, Flats and Pots Growing plants directly in ground beds in the greenhouse and directly in the soil in the hotbeds or cold frames, is rather common. However, the use of flats or plant boxes in plant growing offers a number of advantages as compared with planting in the bed. Transplanting can be done at benches under conditions of comfort and convenience which make for efficiency. Moisture can be more precisely controlled and flats can be shifted if some plants grow faster than others. Plants can be moved with more dirt on the roots, and this is a great advantage when plants are sold and hauled some distance, though, of course, pulled plants are handled more cheaply. On the other hand, the first cost, and the maintenance and storage of the flats must be considered. Flats may be set on the ground in the greenhouse without use of benches. Flats are of many dimensions, ordinarily six to ten per sash or about 18 × 22 inches or 13 × 18 inches outside measure. They may be made of lumber from used boxes, but they ought to be uniform in size and made to fit beds without loss of space. The more durable kinds of wood, cypress or chestnut are preferred. Some growers make the bottoms of the flats of square-mesh galvanized screen (hardware cloth), about five or six meshes to the inch. This allows roots to penetrate the soil of the beds, permits root pruning by shifting, and there is no wooden bottom to rot. Some growers use clay pots for plants which are receiving special care. Their cost is an obstacle though they are used repeatedly. Such pots also hold less soil for the area occupied than flats or square dirt bands. [Illustration: FIGURE 12.--Plants for the early crop. 1. Shows plants in paper bands of excellent proportion and thrift but not yet in bloom. 2. In blossom but fruit has not yet set. 3. Similar to 2 but a little further advanced and has actually set fruit.] Paper pots are used to some extent. Organisms decomposing the paper may use and so render unavailable some of the nitrogen of the soil thus hindering the growth of the plants. This may be corrected by seeing that abundant nitrogen is present in the soil either when made up or by later application of nitrate sowed upon the soil while plants are dry or applied in solution in watering. Dirt bands of veneer are used and are very satisfactory. Blocking as practiced by many growers is a cheap and effective way of attaining much the same results. The Blocking System