There is no part of the greenhouse structure that has received more experimenting of late years than the benches or beds. The quick and continual rotting of the ordinary hemlock or pine benches is the cause of that, for it is a big item of expense. There are so many different styles of benches and semi-solid beds, that it would be tedious to describe them all and I will only describe those I consider best adapted for the different kinds of houses.
First then in a house of moderate width, with side walls of wood, anything but a raised bench would be out of the question, as a low bed would not receive sufficient light. For raised benches we have lately received a boon, we think, in the so-called pecky cypress. We had a carload of this material laid down in Buffalo at not more than five per cent cost over hemlock. It is rough looking stuff, and you would think some species of borer had riddled the tree, but it is not the work of borer or worm, for this material comes from the heart of the tree. Reliable men tell us it will outlast hemlock three or four times. If so, then it is a boon. All sizes of this lumber can be procured.
Another raised bench is a framework of l 1/4-inch pipe and crosspieces of tee-iron on which are laid hollow tile or brick. These are made in many sizes. A convenient size is ten inches wide, thirteen inches long and two and one-half inches thick. This makes a fine bench, either for planted out stuff or plants in pots. Many growers in place of the hollow brick use for bench floor a common 2-inch round tile, which is about three inches outside. As tile now enters very largely into bench and bed construction its expense depends on how near you are to a manufacturing yard.
Where it is but a short and direct railroad haul, you will find both the hollow brick and the tile cheaper than 2-inch plauk and then think of the excellence of the drainage qualities and the durability.
For a semi-solid bed there are many different methods. A low wall of cement, say one foot high, four inches at bottom tapering to two inches at top, then filled in with six or seven inches of rubble stone and finished off to the top with your compost. One very large grower of roses tells me he wants no other bench.
A bench I prefer is the cement walls filled firmly and evenly to the top with any old soil you have, then a floor of the hollow brick or 2-inch tile and a cement edging of four or five inches. This would be very nearly everlasting and would bring the surface of the bed twenty inches above the floor, a good convenient height for anything planted out. The Dale Estate, of Brampton, Ont., which has miles of these beds, instead of cement walls has four or five brick laid up, then filled in with earth and the tile floor and cement edge. This is precisely the same but more expensive than the cement walls.
Now what I am going to say is from observation and some tests with the thermometer. These low beds will be a success or failure depending largely upon where your heating pipes are placed. If your benches are raised and there are two feet of free air space between the floor and the bottom of bench, and your heating pipes are on side walls or partition posts, the air beneath the benches will in time become the same as that of the rest of the house. But where the surface of bed is only a foot or fifteen inches above the floor, the temperature of the bed even where there is tile will be cooler than the atmosphere, and low beds should always have a steam pipe up each pathway. Few rose or carnation growers want heating pipes beneath a bench, but they want them on the sides of benches, as equally distributed through the house and among the plants as possible. The more your pipes are distributed and separated the better the radiation and the greater the saving of fuel.
Rose House, Showing Bench Construction, Brick Walls with Tile Bottoms.