It’s essential to know how to shade a polytunnel in the UK using paint, netting, and curtain. A 2016 study has shown how shading the polytunnel saves energy and water while also improving its microclimate. Additionally, the University of Massachusetts Amherst also noted that it effectively cools the polytunnel at low costs.
Shading the polytunnel doesn’t have to be complicated. Like protecting the polytunnel from winds, light and temperature are outdoor conditions that can affect the structure. Therefore, one must know how to preserve or reinforce the polytunnel in preparation for environmental challenges.
How To Shade A Polytunnel In The UK For Beginners
Shade paint
One of the quickest ways to shade a polytunnel is by using shade paint. Shade paint is a good option if your polytunnel production space has no retractable curtain. You’ll apply it similar to regular paint outside of the glass when the season requires you to.
You don’t have to worry about how long shade paint lasts because it is resistant to showers, and you’ll eventually wash it off anyways once the season ends. The only potential disadvantage with using shade paint is that it’s laborious to apply and remove. On the bright side, it is not an expensive material, which is why you can add more layers as needed or when the paint wears off.
What is whitewash?
When researching for shade paints, you have probably heard of whitewash. You can use this term interchangeably with shade paint since it is the shade compound per se. Therefore, if the shade compound is at a high dilution, it provides less shade, while a high compound concentration means high shade.
The ideal shading factor for whitewash would be 40% because too much can decrease the light conditions and negatively affect the plants. You might also consider other materials that reduce infrared light without affecting plants’ light level requirements. With proper use, shade paint should reflect sunlight and scatters the light well indoors.
How to apply shade paint?
The most common way to apply shade paint is by putting it outside the dry polytunnel glazing material. This way, the sunlight will reflect on the paint and prevent it from entering the polytunnel and increasing the temperature. You can apply the shade compound with a brush, sprayer, or roller in the morning or late afternoon.
However, you want to ensure that there will be no rainfall on that day because if the paint gets exposed 24 or 12 hours after a new application, it may wash off. Afterwards, you can wash off the paint in autumn to ensure that the plants get their light needs during the low light seasons.
Shade netting
External and internal shade nettings are also helpful to protect the polytunnel from harsh sunlight. Inside, you can add a plastic weave shading by securing it with clips onto the frame. This way, you can be confident that there will always be a shade inside than outdoor shades that the weather can wear off. On the other hand, you can also clip the same material or hessian over the roof outside to serve as external shade netting.
Shade curtain
Michigan State University recommends an easy way to control high temperatures and conserve water by using retractable shade or energy curtains to minimise radiant heat loss. Compared to the previous two solutions, shade curtains will be usable both at night and during periods of high light. Applied timing is essential, and those in the vulnerable UK areas will start using this shading technique in late April or early May.
There are many materials that you can use for shade curtains. They include woven or knitted fabrics made of saran, polypropylene, polyethene, and polyester. You can choose the degree of shading they provide and even add ultraviolet stabilisation to help it last longer.
To choose a material, you have to weigh some pros and cons. Saran needs to have slight sagging during installation because it shrinks, but it is fireproof. Polypropylene is durable and resistant to abuse and wear and tear, while polyethene is resistant to mildew and won’t fray when cut.
The best thing about shade curtains is that you can open or close them as needed. You can also choose if you want them gutter-to-gutter or truss-to-truss when installed. Therefore, you have complete control of its configuration.
Importance Of Shading A Greenhouse
Shading a polytunnel would help maintain plant productivity since high temperatures affect photosynthesis and respiration. Some crops like tomatoes will even be affected if they get saturated by light. You might even find it unique how shading can supplement evaporative cooling during warm weather and reduce the risk of burning by maintaining plant leaf temperature.
Conclusion
The polytunnel provides a stable growing environment for our plants, but we must reinforce it to adjust to the external conditions to do its job well. One example is when the sun gets too harsh, so it’s crucial to know how to shade a polytunnel in the UK. You can do this by applying shade paint, shade netting, or shade curtain.
The shade paint is the cheapest solution out of the three, but applying and removing it is laborious. On the other hand, installing a shade curtain is a more comfortable and adjustable way to shade a polytunnel. It minimises radiant heat loss that can even double as an energy curtain as a bonus.
