Top Tips - Growing Under Cover

Extend the growing season and grow under cover. Read our top tips and grow more of what you love, while protecting crops from winter weather and troublesome pests.

Growing Under Cover

Horticultural Fleeces

Growing Under CoverPlants and crops need protection from sub-zero temperatures, and one of the most common methods is by using Frost Fleece Protection. They come in all shapes and sizes and their thickness is measured in GSM (Grams per Square Meter). The thicker the fleece, the more protection it will offer against low temperatures, high winds and harsh winter weather. Tender plants can be particularly vulnerable to frost and will benefit from a thicker 35gsm fleece.

How To Choose
Unsure about which horticultural fleece you need? We'll help you choose with our handy How To Choose A Frost Fleece Guide.


Fleeces made specifically for Covering Plants and Pots will help insulate plants and protect their leaves, as well as prevent soil from freezing and terracotta pots from cracking. Gardening Fleece Blankets allow you to cover veg beds and insulate soil creating better conditions for seed germination. They also provide root veg with great protection from pests, such as carrot fly.

Gardening Cloches

Growing Under Cover - Garden ClocheYoung tender plants and seedlings can be grown under cover with a Gardening Cloche. Cloches are a worthy investment if you have sown hardy varieties of salad, as they will provide crops with a few extra degrees of warmth.
Herbs, for example, can naturally die down for dormancy over the winter, but a cloche can delay or even prevent this. More hardy varieties like mint and parsley will re-sprout again every time there is a mild spell, providing fresh leaves to harvest.

Did You Know?
Dropping temperatures can cause stunned growth and can affect the quality of yields later in the season.


Mini Polytunnels & Growing Domes

If you have the space, Mini Polytunnels and Growing Domes are a great way to extend the growing season, as well as keep your crops protected from frost and pests.

Growing Under Cover - Mini PolytunnelMini Polytunnels can be extended across a bed and are great for covering root veg and other plants. Frost causes the water in plant cells to freeze, and as they defrost quickly during the morning sun it ruptures their cell walls. If plants are covered using a mini polytunnel, they are kept at a consistent temperature, which will prevent damage to plants. The fleece material is permeable to light, air and moisture, which your plants need, but can still keep them well insulated.

Growing Under Cover - Growing DomeGrowing Domes also provide the same benefits on a larger scale. These come in a few different shapes and sizes, with some designed to fit against a wall, which can help keep temperatures above freezing. Positioning either of these in sunny spots of your garden or allotment will help keep crops in balmy conditions as the temperatures begin to drop. Overwintering brassicas such as cabbage, cauliflower, broccoli and Brussels sprouts will thrive in these conditions heading from autumn into winter.

Top Tip
You can water through mini fleece polytunnels and horticultural fleeces. There’s no need to remove them.


If you’re lucky enough to have a few sunny days during winter, it’s a good idea to keep an eye on humidity levels. Opening vents or the ends of tunnels will give your plants a welcome dose of fresh air, which can help prevent fungal infections. A Thermometer & Hygrometer will monitor temperatures and humidity levels so you can be sure your plants are in the correct conditions.

Cold Frames

Growing Under Cover - Cold FrameIf you have a number of tender or tropical plants in the garden, a cold frame can be their new home over winter. They provide plants with conditions for a gentle dormancy, and by spring time, they will be raring grow!

Keeping soil moderately moist but not wet is key, as the plants won’t need much water over winter, and overwatering them can cause rot.

Top Tip
Extend the growing season & overwinter plants by using your Vitopod Propagator as a cold frame or mini greenhouse. Read more.


Cold frames can also be used to harden off plants. When plants are moved into the garden from a greenhouse or indoors, they need to get used to their new environment (changes in light, temperature and moisture). Opening a cold frame during sunny spells, and gradually increasing the time it is open over the space of a week can ease seeds into their new environment.

Need further help?

Our Gardening Angels are here to help you grow strong, healthy plants with bumper harvests. Please do not hesitate to get in touch with any questions on 0845 602 3774 or drop us an email at We’re always here to help!