Stocking the Greenhouse with Plants
When you buy and erect your first greenhouse it will look depressingly bare, and you may wonder how you will ever fill it with plants, Do not despair, however; bear in mind that most greenhouse gardeners eventually find themselves at the other extreme and cry out for more room.
Don’t be too impatient to fill your greenhouse. Take your time about selecting plants, and choose those that will be happy together (sharing the same, or very similar, conditions of light, temperature and humidity) and suited to the environment created by your particular greenhouse and site.
If you want some quick colour you can always grow annuals from seed while planning your long-term plant selections.
Mixing and matching plants
There are a number of growing routines that you can adopt using groups or successions of popular plants. For example, you may want to use the greenhouse for raising bedding plants early in the year, followed by tomatoes and then chrysanthemums. Alternatively, you might want to specialize in vegetables such as cucumbers, melons or climbing French beans, or in flowers such as carnations or orchids. Any other plants must then be chosen to fit in with these.
Your scope for mixing plants is very wide since, by positioning them carefully, you can largely satisfy their individual requirements. For instance, you can shade the glass immediately above plants needing deep shade or else put them under the staging. Put plants demanding plenty of light as near the glass as possible and well away from others that might cast shade. Stand plants preferring high humidity on moist shingle, and keep those that like drier air on slatted staging.
Trouble arises, however, when you try to put together plants with widely differing demands, such as mixing tropicals, sub-tropicals, alpines, succulents, semi-aquatics, sun or shade lovers and hardy plants. Of course there are always a few examples of these groups that seem more tolerant of conditions that are abnormal to the group as a whole. For example Aphelandra squarrosa (zebra plant) is from warm parts of Brazil, yet it can be acclimatized to a quite cool greenhouse. Numerous succulents also make themselves at home in fairly moist conditions.
Using the whole greenhouse
When stocking your greenhouse, you must also remember that plants have many different habits of growth. It is not only their height that varies; they may become bushy, grow erect, trail or hang, climb, or be capable of being trained into standards or other shapes. It is by exploiting the many different and exciting shapes of plants that a really attractive greenhouse is created.
The greenhouse should be able to cope with these variations, if you arrange to have shelving that can be set at different heights and make provision for pots or baskets to hang from the roof — remembering that such containers can be very heavy when filled with moist compost. You can also install staging of various heights and leave parts of the greenhouse clear so that plants can be grown from floor level to the full house height. For climbers, wires or plastic netting fastened to one side (particularly in a lean-to) may give you further scope.
You should be able to plan your greenhouse so that there is as much ‘going on’ in winter as in high summer Plants like cinerarias, calceolaria, primula, browallia, schizanthus and annuals such as salpiglossis will give colour from late winter to late spring (January to April), especially if batches of seed are sown in succession. Remember that variety may greatly influence the time of flowering and by choosing several varieties you may enjoy the same type of flower for a longer period. For example most of the compact-growing cinerarias will flower early, perhaps even in mid winter (December), while the large, exhibition kinds usually flower much later in spring. The same can be said for calceolarias, of which the newer F.1 hybrids are remarkably quick-flowering. In the case of bulbs, too, there are specially-prepared kinds that you can force gently for early flowers, keeping their untreated counterparts for later blooms.
In the decorative greenhouse orevergreens will provide attractive foliage through winter, but select them carefully to avoid creating too much shade. This is especially important when choosing and siting evergreen climbers.
Better house plants
The present-day range of house plants provides many exciting evergreens and some gloriously exotic foliage. Although popularly described as ‘house plants’ they often do far better in the greenhouse because of its higher humidity. However, these house plants must always be selected with their minimum temperature requirement in mind. Avoid buying those needing more warmth during the winter. Unfortunately many come onto the market in mid to late winter (late December) and they may have been standing in chilly, draughty florists’ shops for some time. These plants take some weeks to show the effect of such treatment, so don’t be surprised if they suddenly wilt or drop their foliage after being transferred to your greenhouse.
Acquiring healthy plants
Be critical about accepting plants and cuttings from other gardeners. These may have been passed on because the originals were rampant and weedy. Many poor-flowering impatiens (busy Lizzy) are acquired this way. It is better to wait for plants of which you know the botanical origin, and the variety and name. Remember that there are many specialist growers who sell only healthy plants that are correctly named These are the people from whom to buy plants like orchids, carnations, alpines, begonias, streptocarpus, achimenes, pelargoniums, fuchsias, virus-free fruit (including strawberries), cacti and other succulents, bulbs and other storage organs, and the many other popular favourites for growing under glass.
Growing from seed
All greenhouse gardeners should make themselves familiar with the techniques of growing from seed. Numerous delightful and uncommon plants can be obtained this way. As well as the good selection of popular greenhouse plants that you can order from the general nurseries or seed suppliers, there are rare and unusual plant seeds to be obtained from specialist seed suppliers.
Many house plants can also be raised from seed, including palms and cacti.