PlantSowGrowWhat to sow and plant in September
Main crops come in and planting for next spring begins: spring bulbs, overwintering onions and hardy perennials go in while the soil is still warm.
Timed for a typical UK garden (last frost mid-April, first frost late October). The PlantSowGrow app dates every job from your own town's frost dates.
Sow outdoors in September 12
Straight into the ground, a raised bed or pots outside.
🥕 Vegetables 10
🌿 Herbs 1
🌸 Flowers 1
Plant in September 27
Young plants, sets, tubers and bulbs into the ground.
🥕 Vegetables 4
🌿 Herbs 1
🌸 Flowers 22
Ready to harvest in September 86
What you can be picking or lifting this month.
🥕 Vegetables 48
🍓 Fruit 7
🌿 Herbs 18
🌸 Flowers 1
🌳 Trees 12
Jobs for established plants in September
- Trim After FloweringAgapanthus (Headbourne Hybrids)
Cut the flower stems to the base, unless you want the seed heads for arrangements.
- Bring IndoorsCalamondin Orange
Before the first frost, move the pot to a bright, cool room (10–15°C) and switch to winter citrus feed.
- Summer PruningCherry (Morello)
Morellos fruit on last year's shoots: after picking, cut some fruited shoots back to a young replacement shoot.
- Autumn Pest & Disease CheckCherry (Stella)
Perform a final inspection for any lingering pests or diseases before the tree enters dormancy.
- Let the Leaves Die BackCrocosmia (Lucifer)
Leave the foliage for at least six weeks after flowering, until it yellows — don't knot or cut it. Then tidy it away.
- Trim After FloweringDaylily (Stella de Oro)
Cut the spent flower stalks to the base and pull away dead leaves.
- Trim After FloweringEscallonia (Apple Blossom)
Trim lightly after the main flush of flowers.
- Cut FoliageEucalyptus (Cider Gum)
Cut stems of silver leaves for vases and wreaths.
- Deadhead and FeedFreesia (Single Mixed)
Snap off faded flower heads (not the leaves) and give a high-potash feed to build up the bulb for next year.
- Remove Flower HeadsGarlic Chives
Cut off flower heads before they set seed, or garlic chives will pop up everywhere.
- DeadheadHebe (Great Orme)
Shear off the faded flower spikes.
- Cut Out Fruited CanesJapanese Wineberry
Cut the canes that fruited this year to the ground and tie in the new ones for next year.
- Thin After FloweringJasmine (Common White)
Thin out crowded and flowered shoots back to a strong side shoot.
- Bring IndoorsKumquat (Nagami)
Before the first frost, move the pot to a bright, cool room (10–15°C) and switch to winter citrus feed.
- Bring IndoorsLemon (Meyer)
Before the first frost, move the lemon to a bright, cool room (10–15°C) or frost-free greenhouse. Switch to winter citrus feed.
- Bring IndoorsLemongrass
Bring the pot indoors before the frost and water sparingly in winter.
- Let the Leaves Die BackLily (Stargazer)
Leave the foliage for at least six weeks after flowering, until it yellows — don't knot or cut it. Then tidy it away.
- Bring IndoorsLimequat
Before the first frost, move the pot to a bright, cool room (10–15°C) and switch to winter citrus feed.
- Summer PruningMirabelle Plum (de Nancy)
Prune after picking, never in winter (silver leaf): remove dead and crossing branches.
- Bring IndoorsOrange (Sweet, Pot-Grown)
Before the first frost, move the pot to a bright, cool room (10–15°C) and switch to winter citrus feed.
- Mulch TreePeach (Peregrine)
Apply a fresh layer of organic mulch around the base of the tree.
- Check for Vine WeevilPolyanthus (Primula)
Wilting pot plants may have vine weevil grubs in the roots; tip out and check, or use a nematode drench.
- Trim After FloweringRed Hot Poker (Kniphofia)
Cut the spent flower spikes to the base.
- Check for WoodinessSage (Common)
Sage gets woody after 4–5 years. Take softwood cuttings in summer to replace old plants.
- DivideSorrel (Broad-Leaved)
Every 3–4 years, lift and divide the clump.
- Trim After FloweringStar Jasmine
Trim back overlong shoots after flowering.
- Bring IndoorsStevia
Bring indoors before the frost and water sparingly through winter.
- Bring IndoorsVietnamese Coriander
Bring indoors before the first frost; keep on a bright windowsill.
- Remove Dead PadsWater Lily (Hardy)
Pull off yellowing leaves and spent flowers so they do not rot in the water.
- Cut and Rake OffWildflower Meadow Mix
Cut the meadow to 5–10 cm, leave the hay a few days to drop its seed, then rake it all off — removing it keeps the soil poor.
- Trim After FloweringWinter Savory
Shear off the faded flower stems.
Other months
What to sow in January, What to sow in February, What to sow in March, What to sow in April, What to sow in May, What to sow in June, What to sow in July, What to sow in August, What to sow in October, What to sow in November and What to sow in December.