In our enthusiasm for gardening that bubbles up in the first warm days of the year, we enthusiastically purchase and plant out new plants, including delicate flowering annuals. If the temperature drops overnight, they're very vulnerable to frost damage. Luckily, there are simple steps to take so we don't have to watch our plants suffer.
In the spring, it's quite common for the temperature to drop to below one or two degrees Celsius overnight, creating a display of morning frost that, while beautiful to look at, is not so wonderful for your plants. Many outdoor plants remain unaffected, but flowering annuals like daisies, begonias and geraniums that have overwintered in a greenhouse and aren't used to cold temperatures can suffer terribly. Other plants at risk are vulnerable Mediterranean varieties, like the citrus tree or pomegranate. The risk of night-time frost diminishes tremendously after the middle of May.
WHAT CAN GO WRONG?
Frost damage is caused when the water in the vascular bundles of your plants expands as it cools and freezes. It causes tears and splits in the plant cells, damaging them from the inside, and even causing them to die. It can also be caused by a biting cold wind. Plants in pots are at greater risk than plants in the soil, and they need to be protected.
HOW TO SAVE YOUR PLANTS FROM NIGHT FROST
Place your plants in a sheltered spot, well protected from the wind and close to the house, where it is warmest. Wrap them up in bubble wrap to protect them, as it acts like a nice, warm jacket. When parcels are delivered to you, upcycle the packaging by saving it to protect against early-year frost.
Step by step
Collect a vulnerable plant, a few long bamboo sticks, garden shears, bubble wrap and clothes pegs.
Push the sticks into the soil around the plant to create a framework for the bubble wrap
Place the pot in the middle of the bubble wrap and drape it up and around the frame. To ensure that everything stays firmly in place, clamp the plastic to the poles with clothes pins.
Bring together the bubble wrap at the top of the plant and fasten it securely with clothes pins, so that the protection is more or less airtight. Your night frost screen is ready for action.