Assuming you have sufficient space for a choice
of greenhouse sizes, the next major consideration is what use will you
make of your greenhouse?
If you plan to grow plants inside your greenhouse such
as tomatoes or other heat loving vegetables, carefully measure out how
much space these plants will take up.
Remember that plants growing in the soil inside the
garden greenhouse will not be happy if benches are placed above them. It is a
good idea to plan out the benching in your proposed greenhouse before you
buy the greenhouse to get a good idea of the space which will be
One activity you will almost certainly want to do is raising
plants from seed and cuttings. This will require some form of benches to
work on and place the plants on when they are establishing themselves.
Think carefully about the space these plants will need, not just at the
beginning of the season, but immediately prior to be planted outside. It
often comes as a shock how much space a few dahlias will occupy when they
are large enough to be placed outside.
One space consideration often overlooked is the tools and equipment
you will want to store in your garden greenhouse. A bag of compost, a few hand
tools, pots and containers - these all take up valuable space. A
greenhouse and workshop combined (see the picture above) may be the
solution to your space problems.
A mistake often made is to buy too small a greenhouse initially with
the thought that another greenhouse can be added later. Two facts weigh
against this method of expansion. First, the larger the greenhouse, the
more cost-effective it is. Just divide the floor space in a greenhouse by
the cost to find out how much each square metre or yard is going to cost
you. It will quickly become apparent that one large greenhouse is far
cheaper to buy than the equivalent two smaller greenhouses. That's aside
from all the extra effort in erecting two greenhouses compared to one
larger one. Always go for the largest greenhouse that space and money
One more factor in favour of choosing a large size of greenhouse is
that the larger the greenhouse the lower the cost of heating it will be
per square metre / yard. A larger greenhouse also mean that a more even
temperature can be maintained.
The final consideration in greenhouse size is headroom! If you are
tall consider carefully how much of the greenhouse will be available for
you to move around in. And please, take good note of the height of the
entrance to the greenhouse. Countless heads bear the scars of being hit
whilst entering a greenhouse!