Polytunnel Maintenance Guide

So you've chosen the perfect Polytunnel and had it installed in your garden...

You've filled it with plants, fruits, seeds and vegetables and are enjoying your extended growing season. But if you want to ensure your polytunnel lasts in tip-top condition for many years to come, you'll need to care for it every now and then. So we've produced this polytunnel maintenance guide to give you all the tips you need for making the most of your greenhouse long into the future.

The Annual Clean

The best time for this task will be over the autumn season, before it gets too cold to leave your plants outside. You’ll need to empty your tunnel beforehand so pick a day when it’s not too chilly or windy to avoid damaging any of your plants. Take everything outside - pots, seeds, trays, plant labels - the lot.

For tunnels that are up to 3m/ 10ft wide, we believe a single individual is able to do the job. Simply wash the outer cover with water whilst carefully using a soft broom to brush off debris and algae that forms on the outer layer of the tunnel, then simply rinse away. Be mindful to perform this task as gently as possible to avoid creating any tears or damage to your polytunnel cover.

Inside of the tunnel should also be cleaned with a use of sponge and cleaning fluid that is designed to remove organic bacteria such as algae. This will help disinfect the area where bacteria have built up. Wipe down surfaces to ensure they are pest-free as you don’t want any bugs hibernating in there, ready to eat your crops come next spring. Additionally, give all the pots and containers you’ve taken outside a thorough wash to disinfect.

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Check for Damage

As you prepare for the winter, be sure to look for any damages around areas where the metal poles and the polytunnel cover meet, as long exposure to the sun can heat the metal frame poles and consequently damage the polytunnel cover. This is particularly more evident during the summertime when the sun is out in full bloom. To prevent this from occurring, we highly recommend using anti-hotspot tape, which acts as insulation between the polytunnel cover and metal frame poles. Another essential pre-winter job is to check your polytunnel cover for any tears or holes that may have occurred over the previous months. These can usually be fixed with polytunnel repair tape, which can be a crucial tool to have in hand for cases such as these. Over the coming months, you can expect lots of icy winds, and even a little draught can cause your plants to suffer.

Additionally, be sure to check for any pests that may be harbouring around or inside your polytunnel. Insects such as slugs and snails are notorious for eating vegetation, especially during the winter period when the polytunnel acts as the perfect refuge for them. If there is a presence of rodents in your tunnel, we suggest that you try and get rid of them before the beginning of the winter period as they are sure to do damage to your treasured plants and vegetation. Unless you’ve got yourself a handy barn cat ready for the task at hand, we recommend using one of the many pest control products we have on our website, including a vast range of humane, non-lethal traps that are designed to safely capture pests.

Humidity Control

Keeping tabs on the temperature and humidity in your greenhouse will provide the best growing environment for your fruit and veg. Since the soil in a greenhouse is often self-contained, it’s important to top it up with water as the moisture will be used up or evaporate. Ventilating your polytunnel is also important to deter mould and excess condensation, which is why we suggest leaving the door open when possible during the day to allow trapped air to escape.

For all plants, it's important to maintain the temperature of the water you use because if the water is too cold relative to their own temperature, it can cause damage. So rather than using water fresh from the tap, fill up a watering can and leave it in the greenhouse to adjust to the ambient temperature first. While your plants will also require attention over the winter period, we understand that not everyone may be able to leave the comfort of their home to do so due to varying reasons. This is why we recommend using an irrigation system. Having this system in place means that your plants & vegetation are watered regularly on a set time, leaving you with one less thing to worry about.

For the winter season, we also recommend using a heater to keep your plants growing well. Just be sure to check in on this regularly so the greenhouse doesn’t become overly warm - and remember to keep the space ventilated for brief periods even when it’s cold.