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Plus pic of brussels sprouts for roundell

Autumn propagation.

Spring is often the time when most people think about propagating plants from cuttings, but autumn is also a good time for many plants. In fact, nurseries take cuttings from many shrubs and evergreens at this time of the year to produce young rooted plants for next year. Traditionally cuttings would be rooted in cold frames or outside in sheltered beds and covered over with low cloches for protection from heavy rain and snow. The prepared cuttings would be inserted into the soil after improving it with sharp sand and grit and there they would sit until next year. Over the winter months the base of the cutting forms a callus and early next spring new roots would develop. This method of propagating plants was very cost effective because no heat is required and it also spread the work of the nurseryman over the year. Nowadays, modern propagation techniques have moved on and most shrub cuttings are rooted in polytunnels or greenhouses where heat and humidity are carefully controlled to create the optimum conditions for rooting. In a garden situation the cuttings of many popular garden shrubs can be taken now to produce new plants. For the best results you need a small heated propagator that can be positioned in a greenhouse, conservatory or even a windowsill. The types of cuttings that can be taken at this time of the year include most evergreens such as cotoneaster, hebe, laurel, euonymus, rosemary and sage. Select a short stem from the plant and trim neatly just below a leaf joint and then remove the lower leaves. Insert the prepared cuttings into small pots or deep cell trays and stand them in the propagator where the gentle base heat will encourage rooting. Through the winter months keep the compost moist and occasionally mist the foliage to keep it fresh. Next spring roots will develop and once the cuttings are properly rooted they can be potted and grown on.

Readers’ Questions

Geoff has emailed me about his greenhouse where he in overwintering tender plants. He has a small heater, but wants to know how to check it is working properly at night at night.

Most electric greenhouse heaters have a built in thermostat, but they don’t usually have temperature settings, so you need to regulate the heater to the greenhouse. This is very simple to do by using a maximum-minimum thermometer that registers the highest and lowest temperatures over a given period.

Place the thermometer in the greenhouse (out of direct sunlight) and turn on the heater. Check the thermometer and when the temperature reached the desired heat, carefully turn the thermostat until the heater clicks off. When the air cools down, the heater will automatically switch on and run again to raise the temperature. Ideally leave the max-min thermometer in the greenhouse so that you can check the reading daily to make sure the heater is working properly. In your email to me you didn’t mention the type of plants, but most tender plants will be fine with just a few degrees above freezing.

Jobs for the week.

Check water butts and make sure they are properly connected to the down-pipe and there are no leaves blocking the gutter.

If you are growing Brussels sprouts, check through the plants and remove the lower, yellowing and dead leaves. This tidies up the plants and also helps control brassica whitefly.

Check apples that are being stored in sheds and out buildings. Any fruits that have started to rot should be removed straight away before the rot spread to healthy fruits.