The hot, dry conditions caused by direct sunlight coming through greenhouse glass in spring and summer can scorch plant leaves, encourage pests such as red spider mite and lead to the patchy ripening of greenhouse crops such and tomatoes and peppers.
As well as ensuring good air circulation and humidity, you can create shade in the greenhouse to make it a less extreme growing environment. This mimics conditions typically found in a tropical jungle, enabling your plants to thrive without being fried.
Greenhouse shading doesn’t have to be complicated or expensive – the main aim is to reduce internal temperatures.
As summer ends, shading paint should be removed as soon as outside temperatures fall and you can control overheating with ventilation. If possible, blinds and netting should be rolled up but kept in situ, so they can be used to retain heat on winter nights.
Discover three methods of shading your greenhouse, below.
Use external shade netting
A large piece of plastic weave or hessian can simply be thrown over the roof on the outside of the greenhouse. Use clips to fix it into place or make sure it’s large enough so the edges reach the floor, where you can weigh them down using bricks or large stones.
Use shade paint
Greenhouse shade paint is easy to apply to the outside of the glass as and when you need it. It’s shower resistant and effective, but remember to wash it off again towards the end of the season.
Using internal shade netting
Plastic weave shading can be fixed, tightly, to the inside of your greenhouse, creating a neat solution that isn’t affected by weather conditions as would any material used outside the frame. Standard clips that attach to the inside of the frame of most greenhouses can neatly secure it.
More ways to protect your greenhouse plants
- Water your plants well – plants which are dry at the roots are more likely to suffer leaf scorch
- Ventilate the greenhouse by opening the door and louvres/widows – air moving over the leaves helps to reduce their temperature
- Keep the greenhouse humid – leaving a bucket or watering can full of water will increase humidity levels
- Use a maximum-minimum thermometer, making sure temperatures don’t exceed 27°C
- If appropriate, fit automated ventilation and shading