Greenhouse Management: Greenhouse Gardening Advice
Greenhouse Management and Tips
In summer, adequate greenhouse ventilation must be given. For general guidance, the ventilators should be opened when the temperature reaches 60 degrees F. As temperatures increase admit maximum ventilation and, if necessary, leave the door open as well.
In winter, very little ventilation may be necessary, but on fine days an air change is of great benefit and opening the ventilators on the side away from the wind may be needed. Avoid cold draughts at all times.
Summer Greenhouse Management
Some shading applied to the glass in hot, bright, weather in summer may be needed. This will reduce the amount of water required and also minimise the risk of bright sunshine scorching the foliage. Proprietary shading products are available, for mixing with water, and applying to the roof, outside, with a syringe, knapsack sprayer or even with a brush. In hot weather, damp down the pathway, the walls and staging, to keep the house cool and to maintain humidity.
Winter Greenhouse Management
If the house is just adequately heated, as with a paraffin heater, it is helpful to conserve heat by lining one side of the house inside, with polythene sheeting. Do not cover the ventilators over or, if this is done, do it separately so that normal ventilation can be given. This insulation is very helpful and should be seriously considered. The polythene can be lightly tacked on to the sash bars, or with spring clip clothes pegs if the house has metal sash bars. Polythene sheeting can be obtained from most garden sundries shops.
In hard, severe spells, extra protection may be needed for some plants, by covering them at night, with newspaper. Keep the house and plants rather dry in severe frosty spells. Growing plants should be watered only when they need it, and plants like geranium stools can be left quite dry for long periods, but not so dry that the stems shrivel.
Raising Bedding Plants in the Greenhouse
Several subjects can be raised, in a heated greenhouse, for April and May planting and they can be raised quite easily on a small scale.
The basic requirements are some pots in which to sow the seeds and some seed boxes into which theare pricked out (transplanted). It is possible to buy seed for raising these subjects and for growing the plants in trays, where no compost of one’s own making is yet available. Where the latter is possible, use 3 parts loam, 2 parts of compost passed through an 1/8 inch sieve and 1 part of coarse sand.
The sowing is done as follows: 5in. or even 3-1/2 in. pots can be used but, assuming the former, place two or three pieces of crock (broken pot) over the drainage hole in the bottom and fill to 1in. from the top withmixture. Level the surface and firm this with the bottom of an empty 5 in. pot.
Sow the seed thinly (for guidance 40 to the square inch), and cover it by using a fine mesh sieve if available; if not, place the coveringover the seed by hand. The depth of covering varies according to the seed but is about An. for many flower seeds. Those which are very small, almost dust-like, are barely covered.
Speaking of small seeds, bear in mind that a good way with subjects like lobelia is to sow the seeds on a sheet of white paper cut to the size of a seed tray, then pour them into the screw top from a small bottle and use this as a measure.
The method of sowing larger seeds is the same, although those which can be easily handled, such as sweet, may be space sown, an inch or so apart in the box. Broadly speaking, the larger seeds may be covered in the fine surface soil to a depth of about double their size. It is a good plan to water the soil an hour or two before sowing the seeds, the covering soil used after sowing being, however, of just the customary moisture content.
After sowing, water carefully with a fine rosed can, and place a sheet of glass over the top of the pot, covering this with a sheet of brown paper. Stand the pots on a bench or staging in the greenhouse.
Examine the pots for water requirement each day, and remove the glass when there are signs of germination. As soon as the seedlings are large enough to handle transplant them into a seed tray, 9 the long way and 6 across the tray. Transplant firmly but with care to avoid damage to the small stems. Make sure the compost is level and firm. Allow room for watering and fill the trays to about 3/4 in. from the top, with this factor in mind.
A marker should be made to facilitate pricking out. What is needed is a piece of wood 1in. thick, cut to the size of the inside dimension of the tray. Drive 54 studs in one side, equally spaced, which when pressed into the surface of the seed tray will make the positions where the seedlings are to be transplanted.
When preparing the seed trays, place a 1/2 in. layer of rotted manure or compost in the bottom. This will ensure strong, sturdy plants later. Water the seedlings in, and grow them on, best of all on a shelf, near the glass, otherwise on the bench or staging in full light.
After about 4 weeks in the greenhouse, boxes can be stood out in a cold frame, but this should be kept closed for a few days unless the weather is very warm. Then later, give ventilation by day and, after 2 weeks or so, ventilation by night. After a further two weeks, the lights can be left off and the boxes stood out under a hedge or wall for the final stages of what is called “hardening off”. Throughout this period, water the plants as they need it; avoid over-watering, but do not allow any plants to flag (wilt).
Seeds of the subjects mentioned may be sown in February. This will mean that plants will be growing on under glass in March and be out in cold frames for early April. Most of these are planted out in May.
Not only will the home production of bedding plants save money but you can choose the exact type and colours required for the bedding scheme in mind, and be sure of having the plants exactly when required.