At the end of September the garden still feels unhurried. The soil is workable, the last tomatoes are ripening and the courgette beds are empty. In the lowlands of Central Europe, though, three jobs really do belong in the first half of October. Leave them until the end of the month and you are planting out of habit.
Deadlines that will not wait
| Job | By when | If you leave it later |
|---|---|---|
| Autumn onion sets | first half of October | They fail to root and lift out in a hard frost. |
| Lamb's lettuce | by mid-October | Plants stay too small to harvest under fleece. |
| Daffodils and crocuses | by mid-October | Bulbs dry out in the bag and flower poorly, or not at all. |
| Dahlias | after the first frost, often around 16 Oct | Tubers lifted while the top is still green store less well. |
| Green tomatoes | before frost blackens the plant | Frozen fruit softens and will not ripen indoors. |
Autumn onion sets: this week, not next month
Overwintering onion sets go in from late September to mid-October. Use sets sold for autumn planting. A large spring set that you never got round to in April will bolt in May and give you a flower instead of a bulb. Set the tip just under the surface, about 2–3 cm deep, 8–10 cm apart, in rows about 25 cm apart. Do not feed with nitrogen now. Unless the soil is dry, do not water. The set should root, not grow leaves for the first frost to burn.
Lamb's lettuce is the last vegetable still worth sowing
Lamb's lettuce (corn salad) takes frost, but it has to make a rosette before winter. In the lowlands, sow by mid-October. Higher up, a September sowing is the reliable one. Cover the seed with about a centimetre of soil, in rows 15 cm apart, and sow thinly. A thick stand rots under fleece in November. Once nights start to freeze, lay horticultural fleece over the bed. A heavy blanket of leaves on the rosettes does the opposite of helping. Harvest whole rosettes, or just the outer leaves, from November to March whenever the soil is not frozen solid.
A bed cleared of tomatoes or cucumbers is fine, as long as blighted foliage went out with the rubbish and not back onto the bed in fresh compost. Mustard sown in the first days of October is no longer a safe green manure. Frost around mid-month often kills it before it covers the soil. On a bed you will not sow until spring, compost or mulch on the surface is the better October choice.
Daffodils and crocuses now, tulips once it cools
Daffodils and crocuses need longer to root than tulips. Their window is September and the first half of October. Plant at three times the bulb's height, nose up, in clumps rather than a row. Leave tulips for the colder second half of October and for November. In warm soil they rot more readily. Depth, voles and what to do with the leaves after flowering are covered in the guide to planting spring bulbs. If daffodil bulbs are still in the bag after mid-month, plant them anyway while the soil can be dug. Late planting flowers less well, but a bag in the shed until spring is a surer loss.
What not to do in early October
- Do not prune fruit trees. Apples and pears are pruned in late winter, once hard frost has passed, not in a wet October. Cherries, plums and apricots are pruned after harvest in summer, or on a dry day in spring. An October wound stays open all winter.
- Do not lift dahlias while the top is green. The first frost, often around 16 October, blackens the stems. Then cut them to about 10 cm, lift the tuber, dry it and store it frost-free, around 5 °C.
- Do not leave sound green tomatoes on the plant through a frost. Pick them and ripen them in a room, not in the fridge. Foliage with blight belongs in the rubbish, not the compost.
- Do not rush garlic on the first of October, but do have it in the ground by the end of the month. Depth and which cloves to use are in the guide on when to plant garlic.
The rest of what to sow and plant this month is in what to plant in October.
Frequently asked questions
Is it too late for daffodils after 10 October?
Not while the soil can still be dug. After mid-month daffodils root less reliably than tulips. Tulips are only just entering their window then, and they can wait until November.
Can I still sow lamb's lettuce?
In the lowlands, yes, until mid-October. Sow thinly, about a centimetre deep, and cover the bed with fleece once nights freeze. Higher up, rely on a September sowing.
When should dahlias be lifted?
After the first frost blackens the top, not before. Around 16 October that often happens, but the frost in your own garden decides. Green stems are still feeding the tuber.