Covering a Polytunnel
A common myth about polytunnel covers is that you need to wait for a warm day or until summer before fitting them.
However, the most popular time of year for the sale of replacement polytunnel covers and for covering a polytunnel is in the run up to and during spring when the British weather can still be very cold.
When it comes to fitting your polytunnel plastic, a warm day is preferable as this gives the polythene more flexibility, but a warm day is not essential for getting the cover tight, especially if you have the option to re-tension the cover after fitting (eg, with Cover Tensioning Tubes or Base Rails).
A calm day, however, is without a doubt necessary as when you open up the sheet of polythene you are effectively opening a large sail. We recommend checking the wind and gust speeds when you are planning your polytunnel cover fitting.
What size of cover?
Gardeners in need of replacement polytunnel covers can calculate the exact size of cover required by entering the measurements of their polytunnel into our online calculator.
We will need to know the length and height of the polytunnel to work out the length of cover required, and the distance over the hoops to know which width of polythene is required. We will also need to know if the polytunnel plastic is to be buried in a trench in the ground or if it is to be fixed to timber or aluminium base rails at ground level to make sure we supply the correct width of cover.
We recommend applying Anti Hot Spot Tape to the hoops prior to covering a polytunnel to protect the polythene from degradation due to friction and the built up heat in the polytunnel frame.
How to cover a polytunnel?
There are two ways of fitting the cover – the first method is to dig a trench around the base of the frame and bury the polytunnel plastic in the ground. The use of Cover Tensioning Tubes allows you to add tension to the cover after it is trenched in. The second way is to fix the polythene to timber or aluminium base rails at ground level – base rails are adjustable to allow for cover tensioning.
Take a look at the video below to see the different ways of how to cover a polytunnel.