There are very few seeds that can still be sown this month: winter lettuces, salad leaves, a few Oriental leaves, and spinach. It is, however, the month to begin planting sets of overwintering autumn onions. Like the Japanese varieties for which seeds could be sown last month, they stay in the ground all winter, grow on in the spring, and will be ready for lifting from June onwards next year.
Peaches and nectarines
Container-grown peaches and nectarines can be planted at any time of the year, though between September and December is probably best. Plant bare-root trees later, preferably in November. Remember that peaches and nectarines will only thrive in the warmth of a sheltered, sunny, south-facing site.
If you didn’t do so last month, plant new strawberry plants – either those you’ve bought or those you’ve propagated from runners. The sooner you plant them, the sooner they will get established and the bigger your crop next year.
Lettuces and other salad crops
Sow winter lettuces, and further batches of salads such as rocket, land cress, corn salad, and winter purslane – under cloches of necessary. A few last-minute radishes may give you a final crop before the end of the year. And spring onions sown now may overwinter ready for next spring.
Plant new cranberry bushes at any time from September to November, or wait until next spring. However, bear in mind that they need acid soil. It may be best to grow them in tubs full of special ericaceous compost.
Plant overwintering autumn onions sets this month or next. Prepare the ground first so the sets go in easily, and add an all-purpose fertilizer. Bury the sets about 7-10cm (3-4in) apart with their tips at or just below the surface of the soil. Although large sets may look stronger and more promising, small or medium-sized sets are less likely to bolt in the spring.
Transplant your spring cabbages this month or next. Whether you’ve raised them in pots or in a temporary seedbed, it’s now time for them to move to their final growing positions. Make sure that they go into ground that has been well firmed down.
This is your last chance to sow spinach, as well as hardy oriental leaves such as mizuna, mibuna, and komatsuna. You may need to cover them with cloches if the temperatures are low at night.