In highveld areas the frost season runs from the end of May to the end of September, although with climate change one never knows what to expect.
Frost cloth is necessary to protect tender leafy vegetables, especially lettuce, shrubs and small trees or saplings. Keep an eye on the weather apps to check for very cold weather and protect when warned.
Tips for using frost cloth
When laying frost cloth make sure that it doesn’t touch the plants otherwise the plants will burn where it touches.
Lift the frost cloth each morning. Leaving it on the beds deprives the plants of sunlight and air. The best time to put on frost cloth is in the afternoon when the air is still warm as the frost cloth traps that warm air around the plants.
Protect taller plants by placing tall sticks or poles around the plant and wrapping the frost cloth around the sticks. The top can be left open but the frost cloth at the top should be higher than the plant. This protection can be left throughout winter as long as the leaves receive enough sun.
Another way to protect small seedlings from dramatic drops in the temperature is to use 2litre plastic cool drink bottles (base removed) as cloche’s to protect small seedlings and lettuce. Leave off the cap so that air can circulate.
Mulch prevents the roots from freezing in very cold areas. Herbs in particular benefit from their roots being mulched.
Watering do’s and don’ts
Do not over water because cold, wet soil encourages damping off. However, under-watering can also stress plants making them less resilient to frost. Rather keep soil consistently moist, especially for lettuce that develops a bitter taste if the soil dries out.
The best time to water is during the warmest part of the day, around mid-morning. Ease up on watering if a cold front is predicted.
Build stronger plants
Strengthen seedlings to resist the cold by using a liquid fertiliser. Foliar feeds improve resistance to cold and plant tonics (kelp and fish emulsions) strengthen the leaves.
Fertilising also speeds up the growth of young plants, especially brassicas like cabbage, cauliflowers and broccoli, so that they are well established before extended cold periods.
Although growth is much slower in winter, flowering plants especially pansies, violas and primulas will benefit from some fertiliser. Water in well after fertilising.
Soil hygiene
If veggies have been plagued by disease, like damping off, bacterial wilt, or spotting of leaves, give problem beds a break by planting mustards as a green manure. They are excellent disease suppressants.
At the end of winter, turn the plants into the soil and let the soil stand for at least two weeks before planting spring crops.
Don’t forget to …
Put out bird seed, suet, nectar, and water feeders for the birds who struggle to find food in winter.
Mark the positions of herbs that die down in winter; then they won’t get dug up by mistake. These include tarragon, lemon balm, lemon verbena, comfrey (in very cold gardens), lemon grass, and sorrel. The same advice applies to perennials that die down in winter like cannas, and other more tropical plants.
Move potted herbs to a sunny, sheltered position so that you have herbs to harvest throughout the winter. Another option is to plant herbs in a hanging basket and suspend it is a position that receives plenty of sun.
Text and images supplied by Alice Coetzee.
