Agriculture Reference
In-Depth Information
If your tunnel is only one year old, you may not think it is dirty enough to warrant
the effort involved, but wiping just a small section on the north side will show
you how big a difference a good clean will make. Be careful you don't damage
the cover when cleaning it, particularly when it becomes more brittle towards the
end of its life. If you get the chance, do it on a sunny day as the higher tempera-
tures inside the tunnel will make the cover more flexible and therefore less prone
to damage.
Even a clean polythene cover does not transmit quite as much light as glass. At
other times of the year this is insignificant, but in early spring seedlings appreciate
every scrap of light they can get. If you have a small greenhouse, use it; if not,
you might consider making yourself a cold frame where you can bring on seed-
lings that don't need heat for those first tentative weeks, as they will do slightly
better there. By the middle of March this difference disappears with increasing
light intensity.
Early spring is also the best time to give the interior of your tunnel a really good
clean. Wipe down the inside of the cover and all the exposed metalwork with a
sponge and a plant-safe detergent. We recommend Citrox for this job because it
is organic and breaks down harmlessly in the soil (which is vitally important
because there is no rain to wash it away). It also retards algal growth and inacti-
vates many of the fungal spores that will have adhered to the polythene during
the autumn and winter, ready to be carried down on to vulnerable new growth
by drops of condensation.
March
March, traditionally a month of unpredictable weather, shouldn't bother the tunnel
a bit. Outside it may be wet, windy and generally unpleasant, but inside the tunnel
spring will most definitely be in the air. It will be warmer, calmer and a very nice
place for gardening. At some point towards the end of the month growth in the
tunnel suddenly takes off and you realise that it's warm enough to bring most of
your early sowings out from their warm windowsills. But remember to watch the
weather and provide protection from any sharp frosts.
This is also the time to start off the next wave of sowings. Put up some staging in
the tunnel so that new seedlings are out of reach of pests, and position it so that
the beds beneath are not shaded. If this will be a problem, making the staging
from wire mesh fastened to a wood batten frame, rather than a board of solid
planks, will allow most of the light through.
March is a good month to bring a chair into the polytunnel, and with all that
activity you're going to need it. Position it close to some staging or a handy table
- then you'll have somewhere to put your tea while you relax!
