Contents
Preface
I. Introduction
II.
Size of the Greenhouse
III.
Structural Details
IV.
Siting and Erecting of a Greenhouse
V.
Plants for a Greenhouse
VI.
General Care of Plants in Greenhouse
VII.
Maintaining the Greenhouse Structure
VIII.
Plant Troubles
Preface
Greenhouse growing is not merely a money making proposition nor is it a simple pastime calling for occasional action. It is instead an absorbing hobby, which enables to produce a range of plants which can be used for commercial purposes also. If used properly greenhouse offers a way to extend the joy of gardening.
Dr. K.T. Chandy, Agricultural & Environmental
I. Introduction
A greenhouse helps in extending the
gardening activities and allows us to grow plants that might otherwise be impossible. Inside greenhouse we have a protected environment and a group of plants which rely on us for their very existence, As a definition, we can state that ŤA greenhouse is generally a place where plants are raised and cultivated rather than set out for display". A greenhouse offers a way to extend the joy of gardening, so it should be used properly. Outdoor, plants are in a environment where one can not control -frost, wind, rain and other environmental hazards. Here the results depends entirely on the type and facilities inside a greenhouse and our own skill rather than on the various of soil type and
weather.
Greenhouses need constant attention at most times of
the year and this means every day in summer unless we
install an automatic ventilator and an automatic watering
system. It should not be considered merely as a money
making proposition nor it is a simple pastime calling
for occasional action. Instead of absorbing hobby which
enables one to produce a range of plants at a time when
the garden counterparts are far C behind or their growth
outdoor is impossible. Judicious use of greenhouses
helps in attaining good profits when used commercially.
Here in a greenhouse there is: a steady stream of
jobs
to do, but none of those is strenuous which makes green-
house growing especially suitable for the not so-young
and the disabled.
A
greenhouse can be used for:
-Producing half hardy perennials or bedding annually grown from seed both during sowing and pricking out.
-Protect tender plants and bulbs during the winter months.
-Grow hobby plants such as chrysanthemums, fuschia's or exotic orchids.
-Cultivate indoor pot plants.
-Cultivate alpine species.
-Use it for commercial purposes.
The site for a greenhouse should be preferably close to main electricity and water supplies. The site should be level, open and should not be sheltered and overshadowed by trees. Ideally oriented so the long axis can lien east-west to optimize the use of light.
II. Size of the Greenhouse
It can be of any convenient size ranging from 6 ft x 4.5 ft to 20 ft to 10ft. Recommending the most suitable size is not an easy task and one has to consider various factors. A tiny house saves money but has two disadvantages.
1.
It is much more difficult to control the environment in a small
house than in a large one, draughts and sudden fluctuations
in temperature are serious problems.
2. Most gardeners find that they need more space after a year
or two; If space is available it is advisable to buy a modular
greenhouse which can be extended if needed.
The most popular size
of a greenhouse is 8 feet long x 6 ft
wide, where space is restricted. If we want to have staging
on both sides of the house, then 10 ft x 8 ft size is advisable.
The size should be in keeping with the area of the garden; a
large green house can be very costly to heat and a structure
which is more than 8 ft well usually need a concrete base.
III.
Structural Details
This comprises of the following details.
A. Frame
Aluminium alloy has taken over as the most popular material
for greenhouse frames for several reasons. It is cheaper than
wood and requires no painting or other treatment and the thin
glazing bars mean more light within the house. There are certain
drawbacks like aluminium greenhouses lose slightly more heat
at night than wooden ones and condensation drips are more likely
to occur. If aluminium frame is poorly designed it may twist
in windy or hot weather and panes may be broken. Now pre-drilled
holes are there on main frame so fixing shelves/ hooks is not
a problem.
Wood is considered by many to be most attractive material. The
main problem is that rot-proof timber is so expensive, teak
and oak are very costly and the cheaper western red cedar is
still appreciably more expensive than aluminium. These rot proof
frames should be rubbed with linseed oil every few years to
enhance their appearance. Fittings should always be of brass
or galvanized iron. If one opts for a soft- wood greenhouse
then make sure that the wood has been pressure treated with
a preservative. Plant safe preservatives should be used for
painting treatment every few years.
Unplasticised rigid polyvenyl chloride (PVC) is the latest material,
which is generally quite expensive but requires little maintenance
and also is decay proof. It requires only occasional washing
to remove dust/ bird droppings. Its main drawback is that, it
is not a strong material, which means that glazing bars have
to be as thick as wooden ones and with large buildings the UPVC
frame requires a metal core.
Galvanized steel is still used in the manufacture of commercial
greenhouses but is no longer popular for home models. The great
advantage of this material is its rigidity and strength, which
means it can support a large roof. This is of little advantage
for an ordinary 8 ft x 6 ft house, and the fact that the galvanized
or painted surface can become scratched and then pitted with
rust is a disadvantage.
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