September, One Foot in Autumn

September has one foot in summer and one in autumn — still harvesting, but it’s also your last real chance to set next year’s garden in motion.

Sow now (outdoors)

Garlic, if the soil’s workable — it wants a cold spell to develop properly, so an early start pays off. Overwintering onion sets. Green manures on any beds you’re clearing. If you’re starting a meadow, sow wildflower seed (and yellow rattle to weaken the grass around it) into cleared, bare soil now — an autumn sowing gives it the cold spell it needs before germinating in spring.

Plant out

Spring cabbage seedlings. Spring-flowering bulbs — daffodils first, tulips can wait until November.

Harvest

The last tomatoes (bring in green ones before a frost, they’ll ripen indoors). Apples, pears, squash, and pumpkins. Maincrop potatoes if you haven’t already lifted them.

Prune

Summer-fruiting raspberries if not already done. Trim back rambling roses once flowering’s finished.

General jobs

Start clearing spent summer crops and add them to the compost. Lift and divide overcrowded perennials while the soil’s still warm. Net brassicas against pigeons as other food sources dwindle. Scarify the lawn to pull out thatch and moss, then aerate any compacted areas — both work best done now, while the ground’s still warm enough for it to bounce back quickly.

This weekend

Get your garlic in if you haven’t — it’s one of the easiest “plant it and forget it” crops, and a September start beats a spring one for bulb size.

A cooler, wetter September in the North, Scotland, and Northern Ireland can mean an earlier end to tender harvests than in the South.