Commercial Polytunnels can be useful structures on rainy days and gorgeously sunny ones – they can be used come rain or shine. But looking at how polytunnels function on a rainy day in a little more depth will benefit gardeners towards wet weather gardening, as well as common problems that can arise during extreme weather.
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Are Polytunnels Suitable for Bad Weather?
Polytunnels are surprisingly resilient structures. They can really come into their own for wet weather gardening, helping you to weather autumn storms in your garden, grow your own food, and enjoy the space even in heavy rain.
Of course, in order for a polytunnel to survive, and for plants within them to thrive, you need to think carefully about where they are positioned and about their ongoing maintenance. When it comes to positioning, thinking about sunlight, wind and water is important.
Water may take a range of different paths when it crosses any piece of land. Understanding how and where water flows on any given site is very important and this understanding can help you to decide whether or not it is a good idea to position a polytunnel in a particular location.
The first thing to remember during wet weather gardening is that water always flows downhill. This may seem obvious, but is surprising how often simple things like this are forgotten when positioning a polytunnel, or any other growing area.
It is best not to position a polytunnel on a slope – at least not an extreme one. One of the main reasons for this is the behaviour of water on that slope during wet weather gardening.
First of all, water can destabilise the soil on steep gradients. This can not only make the structure less stable and secure, it can also lead to run-off and over time, a degradation of the nutrient composition of the soil.
Since water flows downhill, it will often take nutrients with it as it goes, causing soil to become less fertile over time. A sloping polytunnel may also be more of a challenge when it comes to watering your plants, since water will not be retained as effectively for the uptake of plant roots.
Another thing to think about is whether a potential site will become waterlogged or even flooded in future. Locate a polytunnel in a natural dip, or at the base of a steep slope, and the water may naturally pool within it, causing waterlogging or even flooding if extreme weather events are experienced.
As extreme weather events become more frequent due to climate change, you should also think very carefully before placing a polytunnel, or any growing area, on a potential flood plain or too close to a watercourse that could potentially overflow on extreme rainy days.
What is the Disadvantage of a Polytunnel?
Polytunnels can often be a great choice for many locations, but of course not for all. It is important to look at the potential disadvantages of one of these structures as well as the positives to see whether or not one is the right choice for you and your site.
One thing that may be relevant on a rainy day, when temperatures often drop and humidity is high, is that it can sometimes to challenging to manage ventilation correctly.
Should I Leave the Polytunnel Door Open?
Managing polytunnel ventilation correctly is important, especially on humid, rainy days, because without good airflow, plant diseases can become more likely to take hold. In particular, fungal diseases can potentially become an issue.
Having doors at both ends of a polytunnel is a good idea as this will allow for a through breeze which will aid in natural ventilation. So this is something to consider when purchasing a polytunnel in the first place. You may get side ventilation too.
When positioning a polytunnel, it is useful to position it so that there is a through-breeze in summer, while the tunnel is protected from stronger winds.
But even if you have given thought from the start to ventilation, as you should have, you still need to think about airflow and ventilation on an ongoing basis. This means thinking about when the door or doors should be open, and when they should be closed.
There is a balancing act in any polytunnel to maintain the right airflow, temperatures and humidity and to get the balance right.
Opening doors will often reduce temperatures, of course, and increase airflow. It can also reduce humidity though on occasion can increase it too… depending on outside conditions and several other factors.
Over time, you should begin to get a feel for when to open and close the polytunnel doors on your particular polytunnel, in your area and in your specific garden.
10 Ways To Make the Most of Your Polytunnel on a Rainy Day:
Making the most of a polytunnel on a rainy day means thinking about how you might use it when it is bucketing it down outside. Below are a few suggestions for how you can do so:
Collect Rainwater from your Polytunnel
Of course, one of the most important ways to make the most of your polytunnel on a rainy day involves making sure that you are harvesting rainwater from the structure. We cover this in great detail in this guide on rainwater harvesting, which is hugely important in gardening in a sustainable and eco-friendly way.
Get on With Garden Jobs While Remaining Dry
One of the wonderful things about having a polytunnel for wet weather gardening is that keen gardeners can get on with garden jobs even when there is a deluge, while remaining comfortable and dry. With a polytunnel you can grow your own and enjoy your garden whatever the weather is doing outside.
Relax in Your Polytunnel with a Good Book
But as well as being a practical place where you can grow your own food and many other resources, a polytunnel can also be a perfect place to enjoy some rest and relaxation. Put a comfortable seat in your polytunnel and it could be an ideal place to retreat to with a good book.
Make a Soothing Sound Recording
A polytunnel can be a relaxing place at any time, but in some ways particularly so on a rainy day, when you will be surrounded by the white noise of the rain falling on the cover. Sitting inside your polytunnel is one way to make the most of it. But you might also make a sound recording of the soothing sound to enjoy at other times…
Enjoy Rainy Day Activities with Your Kids
Polytunnels can of course be very family-friendly spaces. Parents can enjoy a wide range of different rainy day activities with their kids inside one of these useful and versatile structures.
A polytunnel can be a cram-packed garden which you can work on together. But play spaces and learning zones are also possible within a polytunnel too. A polytunnel can, in essence, become an extra room for you and your family.
Do Some Rainy Day Arts or Craft Activities
A rainy day can also be the perfect time for adults and kids alike to enjoy some creative time, and a polytunnel can be a good space for some artistic endeavours. There are many different hobbies and crafts that you might indulge in within a polytunnel space.
Hang Some Clothes to Dry in the Polytunnel
Rainy days can be frustrating if you have clothes to dry. But in a pinch, a polytunnel can come in handy as a place to hand clothes to dry when it is raining outside, so that you do not have to hang them up to dry inside your home.
Have a Polytunnel Picnic with Your Family
If you have been cooped up inside all day due to the rain outside, an excursion to your polytunnel could be just as good as heading further afield. Blow off the cobwebs, pack a picnic, and lay on an informal spread inside your polytunnel to get out of the house.
Have a Rainy Day Dinner in Your Polytunnel
You could also use a polytunnel for a more formal dining experience. Many of us love to eat outdoors but when dining al fresco is out of the question, eating inside a polytunnel can give us the next best thing. And if you grow food in your polytunnel, you can eat inches, not miles, from where the food on your plate was grown.
Create a Romantic Mood in the Polytunnel
Last but not least, couples could consider getting out of the house to spend some romantic time together in a polytunnel. Cocooned within a polytunnel, with the rain falling outside, romance can reign and couples can get some precious time to themselves.
These are just some ideas to help you make sure that you make the most of your polytunnel on a rainy day.
Can I work inside my polytunnel for wet weather gardening?
Absolutely! One of the primary benefits of a polytunnel is that it allows you to continue gardening activities even during inclement weather, including heavy rainfall. The polytunnel provides shelter, ensuring you and your plants stay dry.
How does rain affect the temperature inside the polytunnel?
Rain can cool the environment inside the polytunnel, especially during heavy downpours. The drop in temperature can be beneficial during warmer months, but it’s essential to monitor the conditions to ensure it doesn’t become too cold for heat-sensitive plants.
Do I need to worry about flooding inside my polytunnel during wet weather gardening?
Properly installed polytunnels should have adequate drainage to prevent flooding. However, during prolonged heavy rainfall, it’s a good idea to check for any water accumulation and ensure that the ground inside the polytunnel is draining effectively.
How can I improve the drainage inside my polytunnel?
To enhance drainage, consider raising the beds inside the polytunnel, adding organic matter to the soil to improve its structure, or even installing a gravel or sand base layer. Properly positioned trenches or channels can also help direct excess water away from the polytunnel.
Backmo, S., (2019) Polytunnel Ventilation. Sara Backmo. [online] Available at: https://www.sarabackmo.com/polytunnel-ventilation/ [accessed 25/08/23]
Elizabeth Waddington is a writer and green living consultant living in Scotland. Permaculture and sustainability are at the heart of everything she does, from designing gardens and farms around the world, to inspiring and facilitating positive change for small companies and individuals.
She also works on her own property, where she grows fruit and vegetables, keeps chickens and is working on the eco-renovation of an old stone barn.
To get in touch, visit https://ewspconsultancy.com.