- Cabbage, cauliflower, sprouts and other Brassica plants get a multitude of pests at this time of year. Use fine mesh to protect vegetable crops against flying pests. It is particularly effective against carrot and cabbage root fly and caterpillars.
- If you would rather not cover your vegetables in net to keep pests off, try regular sprays of diluted garlic spray.
- Fill spaces in the veg patch by sowing quick maturing items such as turnips or, better still, varieties that will provide tasty winter salads like , corn salad (lamb’s lettuce), rocket, and radicchio. These are not hard to grow and will provide tasty, nutritious homegrown salads in the middle of winter!
- Trees that produce fruit with stones, rather than pips, should be trimmed now. Plums, cherries, apricots, peaches and nectarines are best pruned during the summer when they are less likely to get infected with the incurable silver leaf disease. Immediately paint any significant cuts (over 1” diam.) with Seal & Heal wound healing paint.
- Sow seeds of autumn onion [sometimes called Japanese onion] this month for the earliest crop of next year. You’ll be able to buy onion sets next month, but seeds are cheaper!
- Dig up your potatoes. Dry and store undamaged tubers in a dark, frost-free place for winter. Late main-crop and winter salad potatoes will need a little longer in the ground and may put on a lot of tuber growth in the next few weeks. First early, and most second early, varieties will be ready to lift now.
- Sow green manures in any gaps to improve your soil. There’s a good range available from Kings Seeds.
- Watch out for early blight on potatoes. Only a few sprays are effective, so it might be best to cut the tops off if your crop is infected. If you don’t, then the spores can be washed from the leaves and infect the tubers underground.
- Prune out summer fruiting raspberry canes that have finished cropping.
- Order fruit trees and bushes for autumn and winter planting.
- Order strawberry runners for late summer and autumn planting. Don’t forget to order some for planting into grow-bags - or other containers - to force under protection for the very earliest berries.
- Summer prune intensively trained fruit trees. So that's plants which are espalier, cordon, fan and step-over trained.
- Turn your compost heap over and water it thoroughly if it appears dry.
- The decomposition process can be accelerated by mixing in some compost activator. Cover the top with an old carpet to keep in the heat generated by all the useful micro-organisms that will be breaking your garden prunings down to form good garden compost to dig in the borders in autumn.
- Get some more compost tips here:
- Compost heaps can get too dry, so check and soak them if necessary. If they are too dry, the decomposition slows down.
Soils, mulching, weed control, etc
- It’s not too late to mulch your beds and borders to control weeds. Use chipped bark, composted green waste, mushroom compost or decorative gravel.
Greenhouse and protected crops
- Remove the leading shoot when your greenhouse tomatoes have set five trusses of fruit. This will encourage all the fruit to ripen before late autumn.
- Regular feeding with a tomato feed will help this, and also makes the fruit tastier!
- Check greenhouses for whitefly. They are a little bigger than midges and will fly up in clouds if you disturb them. Yellow sticky pads will trap lots of them but don’t use these if you have introduced or are encouraging natural predators. S B Invigorator sprays have a physical (not chemical) mode of action, but you will need to spray very thoroughly. If you have to use chemicals, Provado Ultimate Bug Killer is currently the best available.
- Watch out for red spider mites on greenhouse plants. Symptoms include pale speckles appearing on the shoot tips, webbing of the same areas and tiny insects just visible to the naked eye. Introduce predatory mites as soon as you see this troublesome pest.
- Pot up a few roots of garden mint. Kept inside you will get fresh mint well into winter.
- This is a good time to control vine weevil using a nematode biological predator. It’s simple to water onto pots and borders but make certain that they are wet first and agitate the solution as you apply it.