Agriculture Reference
In-Depth Information
that are just getting going. If you can, hang some staging for them from the storm
braces and crop bars, making sure it doesn't shade anything planted in the beds
beneath.
Tip
Crop bars, S-hooks, clamps and Q-clips
One of the drawbacks of a polytunnel is that, compared with a greenhouse, there
are very few points on the inside of the structure where you can attach strings and
canes, or hang things such as thermometers and tools. Crop bars, usually sold as
optional extras with polytunnel kits, do more than add to the structural strength of
the tunnel; they are also an invaluable means of hanging and securing everything
from shelving to growing strings (see page 51).
Once the polytunnel has been assembled and covered, it is too late to add most
additional clips and clamps, but you can still carefully drill self-tapping screws into
the metalwork of the hoops, provided they do not have to hold much weight.
If using
a drill on the metalwork of a covered tunnel, always exercise extreme caution. A
cross shape of insulation tape over the drilling point will help to stop the drill bit
from slipping, but even so, make sure you have a roll of polythene repair tape
before you start.
A safer option is the simple S-hook, inexpensive and available from any hardware
shop. S-hooks are great for hanging things from the crop bars, and since they are
not fixed they can be moved around as they are needed. Half a dozen of these
handy hooks is a must for any tunnel - for hoses, tools and even your coat when
it's cold outside.
You can also use ordinary spring clamps on tubing anywhere in the tunnel, but
unless the springs are extremely strong, they have a habit of moving when it is
least convenient. When you need something that's rock solid, get yourself a few
Q-clips. These ring-shaped clips can be pushed on to any piece of tubing that isn't
in contact with the tunnel cover, such as crop bars, storm braces and the lower
parts of the ground tubes, and slid to where they are needed before tightening the
securing bolt, which makes them rock solid. Once again, they are not expensive -
although you may need to buy them from a polytunnel supplier such as First
Tunnels (see Resources section), which allows easy ordering of small sundries like
Q-clips and self-tapping screws. Make sure you buy the correct size, as crop bars
sometimes have a smaller diameter than the tunnel frame.
Q-clip
