Benefits of glasshouse growing in winter

Press, 18 June 1982, Page 11

Benefits of glasshouse growing in winter

GARDENING

by

M. Lusty

The winter months can often be most unstimulating for gardening activities, and prolonged wet weather can further restrict attempts to get out and, do something. This is where- the glasshouse can really come into its own for it not only enables the growing of many less hardy plants, but can be used for forwarding a host of different things. Above all, its use is never curtailed by prevailing weather conditions. There are, however, pit-

falls. The ownership of a glasshouse is not plain sailing all the way , to early bountiful crops, pots full of flowers, or easily, raised, cuttings; glasshouse growing requires a different and more thorough approach from that possible outside. One bf the biggest pitfalls or stumbling blocks can be the multi-use to which most gardeners put their glasshouses: raising seedlings; keeping a range of indoor plants; growing-cer-tain crops such as tomatoes; or perhaps to promote rooted cuttings. ..• i 'This combination of activi-. ties can create problems. Different • plants have varying requirements. Cut-, tings, for instance, need more humidity and constant mositure to get a good strike; a crop of tomatoes requires

adequate ventilation and good light. . Disease and pests may plague one lot of plants, and if control is not good there soon develops a build-up within the confines of the glassed area. Bench plants such as indoor plants must be shaded to protect from sun, scorch, or excessive drying out. So must seedlings and 'rooted cuttings, which are not only susceptible to this effect but also to-low humidity.

■As can be seen from the few examples given, it is not easy to provide all these different requirements in one glasshouse, particularly if it is a small one,'as so often is the case. But.it can be done.

One of the simplest ways is to start with a concrete floor, and grow everything in containers. The only exception to this would be to leave a small area for a grape vine or some other plant if desired.

The virtue of a concrete floor is that it allows better hygiene, which is very important in a glasshouse. A bench can be installed on one side for pot plants and raising other things. The bench area can be divided to provide a further enclosed section to raise cuttings and seedlings under a more controlled environment still, of high humidity and constant moisture, by using polythene or glass covers. The concrete floor can be used for growing container crops such as beans, cucumbers, peppers and tomatoes. Container or bag grow-. ing, which is now widely, used by commercial growers, has two big advantages. . .There is no need to sterilise soil each when the crop is finished it can be taken’out and the new planting established immediately. This system enables great flexibility, variation and con-

tinuity limited only, by the desires of the grower. Because glasshouses do provide suitable conditions for the presence and build-up of pests and diseases, hygiene must be good. For instance, white fly and mites can become major problems, and where the soil is regularly planted, especially with a crop like tomatoes, soilborne diseases can develop. Always inspect the entire range of plants on a regular basis. Spray on the first signs of trouble. Don’t wait another day or two to see if there is an increase because problems have a habit of developing very quickly within the confines of a glasshouse. ' Chlorothalonil is a good quick acting general fungicide to use, and acephate is a broad spectrum insecticide, although it will not control mites. Where mites become a problem, a so-called smoke bomb may be the most effective.

Ventilation is important, particularly with some crops and plants. Make sure that the glasshouse you buy has side and/or roof vents.

Shading will be required for some crops in summer while others may require it more permanently. The simplest and least troublesome way .to do-this is with shade cloth which can be draped over the framework/ to suit. The other alternative is a, lime wash. Loss of and retention of heat is the final considera-. tion. In this very brief examination of glasshouse management it can only be touched on here, but this aspect could well command a discussion on; its own. Silver foil, paper lining, clear flat polythene sheet and notably the bubble type, all provide extra insulation, particularly in the unhealed glasshouse.