Martin Fish protects vulnerable plants from the cold
Protect vulnerable plants from cold, wet weather to keep them content
Through the winter months my polytunnel proves to be invaluable for overwintering plants that need just a little protection from the worst of the elements. I use it to house plants such as agapanthus, tulbaghia, shrubby salvias and coprosma that I grow in containers and will withstand some frost, but benefit from protection from very wet or windy weather.
My polytunnel isn’t heated, but remains frost-free when it’s only a few degrees below freezing outside, but if we get minus 5C (41F) outside, the temperature undercover will fall below freezing. The plants I keep in there are fine with several degrees of frost, if their roots are on the dry side, which is where the polytunnel comes into its own. It’s amazing just how cold a temperature plants can stand if they aren’t in wet soil or a damp atmosphere.
My plants have now been in the tunnel for around three weeks and since then we’ve had some frosty nights, but the plants all look fine and healthy.
To keep them ticking over, I check them on a regular basis and pick off any yellow or dead foliage to prevent fungal diseases or mould setting in. With deciduous agapanthus, for example, I’ll remove dead foliage and put a little dry compost over the crown for some extra protection.
Compost in the pots is kept just moist and the only time I water is if I think it’s starting to dry out too much. A good way to gauge this is to lift the pot and feel the weight.
With a dry atmosphere and good air circulation through the mesh door, the plants tick along nicely. If the weather does suddenly turn much colder, I’ve fleece on standby and I’ll wrap several layers over and around the plants to keep them cosy.