January, south of the equator

January is the middle of summer and the month that asks for water rather than work. Inland the thunderstorms arrive most afternoons and the garden grows visibly between one week and the next. In the winter rainfall parts of the Cape it is the dry season, everything is baked, and the job is keeping alive what you planted in spring.

In the garden

Sow for autumn. Beans, beetroot, carrots, radish, Swiss chard, lettuce and cucumber all go in now, and a January sowing of cosmos flowers when the summer annuals are finished. Sow into a drill that was watered the night before, and shade the row with a board or a branch for the first week, because bare summer soil dries within hours of a watering.

Feed and water the things that are working. Tomatoes, peppers, courgettes and cucumbers are all swelling fruit and every one of them is mostly water. Deep soaks twice a week beat a daily sprinkle. Mulch anything that is not already mulched, which is the single most useful thing you can do in a hot month.

Keep picking. Beans stop the moment a pod is left to swell, and courgettes turn into marrows in two days. Deadhead the annuals, cut lavender for drying, and take softwood cuttings of pelargonium, lavender and rosemary, which root within a fortnight in this warmth.

In the house

The plants are working harder now than at any other time. Water on the shortest interval of the year and feed every fortnight, and expect a plant in good light to make a leaf every couple of weeks.

Watch the light rather than the temperature. Summer sun through a north facing window in the southern hemisphere is strong enough to burn foliage that has spent the winter in a dim room. Move plants back half a metre or filter the light, and remember that the mark left by scorch never fades.

Keep an eye out for red spider mite, which thrives in hot dry indoor air and shows first as a fine pale stippling and then as webbing in the joints. Check the undersides of the leaves once a week.

What not to do yet

Do not repot in the hottest weeks unless a plant is desperate, because a disturbed root system cannot keep up with the demand for water. Do not plant a new tree or shrub now if you can wait for winter. And do not water a scorched leaf in the hope of reviving it, which is a light injury rather than a thirst one.