This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Some of the difficulties of my subject can be imagined when one considers that hundreds of books and innumerable magazine articles have been written on hothouse management; and also the fact that out of the hundred or more varieties of plants one wants to cultivate, hardly two require the same treatment. It is a fact, that the temperature necessary to grow violets successfully, is so cold as to kill many varieties of coleus. But by judicious arrangement according to their different wants, nearly the whole catalogue, except orchids and a few others can be grown in the same house. Laying aside details, I will try and give briefly the essential points, so that a person of limited experience can easily supply the omissions.
The point of first importance is that of heat. It is hard to prescribe any arbitrary degree at which the thermometer should be kept, for this varies according to the season, and the kinds of plants it is desired to cultivate. My experience has been, that beginners are quite sure to keep a house too warm, on account of a desire to be on the safe side, and lessen the danger of freezing, as well as force the plants into bloom. This is a mistake, and tends to destroy their vitality, and greatly weaken them. For general purposes I think that 55° at the coldest point is about right for the night, and days when the sun does not shine. But when the sun is on the glass, it can safely be allowed to go as high as 90°, without serious danger. The main object should be to maintain an even temperature, and avoid all sudden changes.
No definite rules can be established for watering; one mast simply use careful judgment. If the soil be dry, as can easily be ascertained by the looks or by feeling of the earth,'water freely. Not merely sprinkle the top, but see that the whole is thoroughly saturated. Water if possible in the morning, and occasionally sprinkle the foliage. At all events do not water unless a plant needs it, and to have a plant get a little dry once in a while is better than to have it continually wet.
Ventilation is also very essential, and quite apt to be neglected, unless its full importance is realized. Pure air is as necessary to plant life as human life, and without a judicious use of the ventilator, one cannot hope for success in winter gardening. Admit fresh air during the middle of the day, more or less, according to the severity of the weather. Never open the ventilators during a damp or dark day. Avoid having a draught strike directly on the plants. If a green slime or fungus comes on the tops and sides of the pots, reduce the amount of water, and increase the ventilation; Re-pot the. plants so affected, if this does not remove it.
An entire number could well be devoted to the subject of the proper soil, so much of success depends on this point, and so many theories are held by different authorites. Four principal elements are requisite to make the proper mixtures for the different purposes. Good garden loam, manure at least two years old, coarse well-washed sand, leaf mould from old growth hard wood. These in different proportions can be adapted to the wants of any plant; for instance, for newly rooted cuttings use loam mould and sand, in nearly equal parts; for ferns more leaf mould and less of the/others; for repotting old or established plants, use more manure, and so on through catalogue. These points of difference can be ascertained from any good work on horticulture.
In potting see that the plant stands upright, and press the soil firmly down. A gentle rap on the side of the pot will smooth off the top. Newly potted plants should be watered with a sprinkler, as a heavy stream will dig up the roots. With nearly all large plants and geraniums and fuchsias in particular, put some pieces of broken pot for drainage. Never shift plants into larger pots until the roots have reached the sides and bottom of the one they are in. Over-potting is a frequent mistake.
To me the most fascinating part of horticulture is in propagating, and the cutting bed of a hothouse is the first thing I examine. It should be in the shadiest and warmest place. In the plan described in a previous article, it should be just over the boiler, which is on the north side of the walk. The main points for a successful cutting bed are a good heat, and a uniform moisture must be maintained, never allowing it to get dry. Have had a single neglect on this point ruin an entire bed. The cuttings should be placed in coarse white sand, free from iron or other impurities. Wash thoroughly and pound it down firmly before inserting the cuttings. In most cases select wood that is partly matured avoiding weak or soft shoots, for they are sure to "damp off;" cut off squarely just below the bottom joint with a sharp knife, mak-; ing one smooth cut; remove the lower leaves, and in some plants as Coleus and pinks, crop the foliage, but preserve the centre shoot; press the sand firmly around them, and shade from the sun.
Space will not permit more extended directions, but in closing would like to give the result of last year's experiment with my hothouse, the same as described last month.
Cost of running: two tons coal, $8.00 per ton, $16.00; other fuel, $5.00; leaf mould and sand, $2.00; seven hundred new pots various sizes, $11.00; glass and other repairs, $1.50; making in all $35.50.
Now I sold to various neighbors and other hothouses after filling my own garden, which took at least 1,000 plants, enough to amount to $128.50, leaving a handsome margin above expenses for the purchase of new varieties, and some return for the trouble. Having attempted to show the general points of management, in my next will enumerate the best varieties to cultivate and show how to make the most of a little room.