Agriculture Reference
In-Depth Information
Flying insects
The tunnel may seem like an isolated bubble, but in summer you will notice that
it gets a lot of visitors in the form of birds, insects, toads and so on. Your attitude
to this will probably change from season to season and from year to year,
depending on what you are growing. Growing brassicas when there are lots of
butterflies around is an invitation to heartbreak; yet without bees, strawberries
do not fruit so well. There are several options for excluding flying visitors, such
as fleecing or netting particular plants, or making mesh covers for the doors.
Tip
Pollinators or brassicas?
If you need insects to pollinate plants in the tunnel, grow a few flowers. Calendulas,
marigolds and dependable perennials such as dahlias attract all sorts of pollinators
and look good too. But if you grow brassicas you may wish to screen off the doors of
your polytunnel with mesh to keep butterflies out. So which is it to be - pollinators
or brassicas?
Netting curtains or screens using 7mm mesh at the doors will ensure that bigger
creatures such as birds and butterflies can't get in, while hoverflies - important eaters
of aphids that are attracted to calendula and marigold - still can. However, this
also means that bees, the most important group of pollinating insects, cannot.
Please note that butterflies often manage to get through larger meshes, even
though the holes may look far too small for them. Unless you use 7mm mesh or
finer, crops such as brassicas may have to be fleeced for their protection.
The downside of using 7mm netting rather than a finer mesh at the doors is that
while hoverflies may be able to get in, a great many won't be able to find their way
out again and may perish as a result.
May
The eggs of any slugs that evaded you earlier in the year should have hatched by
now, so starting a 'slug patrol' is a good idea. Try to do this with a torch after dark
each evening, as that's when they are out and about, especially on warm, humid
nights. Slug patrols will be needed until the end of the month and possibly
beyond, depending on your circumstances. A combination of slug patrol and the
prompt clearing of potential slug habitat is the best way to control their numbers.
Once things really warm up you will be kept very busy training and pruning, so
again think seriously about fitting an automatic watering system (see page 22).
These don't have to be expensive: a clockwork timer fitted to an outside tap with
a length of soaker hose will do the bulk of your irrigation for you, freeing up vital
time for 'proper gardening'.
