Agriculture Reference
In-Depth Information
Why install in the spring?
When covering a tunnel it is important to get a really tight fit so that the cover
lasts as long as possible. The polythene is at its most stretchy when it is warm,
and installing in cold conditions would mean that everything would have to be
re-tensioned in summer. Although this can be done easily enough, the fit is never
quite as good as it might have been. For the best results, the tunnel cover should
be as tight as a drum in its first year.
That rules out winter, and summer is simply too late to get your hot-weather
plants started. It is tempting to consider an autumn installation, but this leaves
little time to really get things going before winter sets in. Your polytunnel would
just stand there, being battered by the elements while being comparatively
unproductive. Given that a tunnel cover has to be replaced every five winters or
so, this is just not worth it. So, wait until spring. Spend your winter getting ready
for your first tunnel season, because there are quite a few things to do.
Get the beds ready
As soon as the tunnel's hoops are in place, you can not only plan exactly where
you want the beds to go, but you can actually go ahead and prepare them. It will
be far easier to do this before the cover is in place because you can work from any
angle, and because you can move things around in a wheelbarrow without having
to negotiate the doorways.
Most of the work involved in actually putting the tunnel cover on happens out-
side the footprint of the structure, but some things need you to be inside, so care
must be taken not to trample the new beds. Treading directly on the soil com-
pacts it, excluding air and reducing drainage, and this presents a major chal-
lenge to plant growth. Any time you have to step on the beds, use a short plank
or board to spread your weight. This limits the damage so that any affected areas
can be quite easily fluffed up again with a fork after the tunnel is up.
From the moment the tunnel cover goes on, the soil in the tunnel beds is com-
pletely cut off from the outside and becomes totally dependent on you for food
and water. To give you some idea of how seriously you should take this, think how
quickly a grow bag dries out if you forget to water it, and how depleted the compost
is at the end of the season. You will need to start a regimen of feeding and water-
ing the soil from the very beginning, so start right away: gently fork a top dressing
of compost into your new beds and water them before you plant anything. This
gives everything a chance to settle and also gets the earthworms started, distribut-
ing organic matter throughout the soil and reversing any compaction from standing
on the planks. Worms will do a lot of spadework for you, if you let them.
With luck your soil will start off in good health, but if you have used large
amounts of commercial compost to make them it is possible that they may be
