Frost in a greenhouse can affect many plants and is particularly damaging to tender new growth and blossom in the Spring time. Frost can cause plants to become scorched or covered in pale brown patches, alongside damaged blossom and fruits on the plant and in some cases, can kill the plant.
It’s important to look after your plants to ensure they don’t freeze overnight; the last Spring frosts in Essex usually last until late April. The risks of frost damage to your plants can be reduced by taking some simple steps.
Invest in a greenhouse heating system
Electric tube heaters are ideal if you are looking for a heating system that heats up exceptionally fast with running costs as low as half-a-pence per hour – depending on your energy charge of course! Tube heaters are good for heating greenhouses to prevent cold spots and disease forming on plants. The heating will protect plants from becoming a frosted, soggy mush and help keep the young plants snug and warm until Spring time.
Protect the plants
A greenhouse provides much needed warmth for tender or damaged plants. Containers that are delicate or not frost-proof should be moved inside the greenhouse during the colder months to prevent them from cracking.
It’s important to cover up plants before nightfall and water the soil thoroughly, as wet soil holds heat better than dry soil, so the roots will remain protected and warm. Bed sheets, drop cloths, blankets and plastic sheets all make suitable covers for vulnerable plants and use stakes to keep material from touching foliage. When the temperatures rise the next day, make sure to remove the coverings.
Some plants however cope well during periods of frost and continue to grow, including spinach, kale, collard greens, chard and endive.
Add some insulation
As the temperature plummets at night, it’s important to insulate the greenhouse correctly to ensure it stays warm. Line the greenhouse with a layer of specialised insulating wrap, or even some bubble wrap, to reduce heat loss and block icy winter draughts.
Don’t forget to ventilate
The only downside to heating a greenhouse is the increased humidity. Good ventilation is essential because it will prevent the spread of fungal diseases and maintain a healthy growing environment. Moisture can be prevented from building up by watering plants sparingly in the early morning. Open the greenhouse up on warm, sunny mornings to help clear condensation, but remember to close them again before the sun goes down to trap the daytime warmth to keep the greenhouse warmer for longer.