What to sow and grow in September
Sow red hot pokers (Kniphofia) for stunning displays next summer
Image: Kniphofia uvaria from Thompson & Morgan
September might be peak harvest time, but there’s still plenty to sow and grow this month.
Here's a handy list of what to sow in September, including all the flowers, fruits and vegetables to keep your garden ticking along:
Flowers to sow and grow
In the greenhouse/indoors
- Surface-sow euphorbia seeds now in trays indoors.
- Sow dierama seed now on the surface of moist compost. Keep in a cool greenhouse over winter.
In the cold frame / under cloches
Direct sow outdoors
- Sow Ammi majus ‘Graceland’ (Bishop's Weed) directly in the ground now where you'd like it to flower. Autumn sowing will produce bigger, more robust plants to grow.
- Sow hardy geraniums outdoors and leave them to over-winter.
- Direct sow hardy annuals, such as cornflowers, poached egg plant, annual poppies and larkspur 'T&M Improved', for bigger plants next year.
- Sprinkle California poppies into your borders for stunning colour late next spring.
- Direct sow Love-in-a-Mist (nigella) — it will over-winter quite happily and will self-seed prolifically!
- Sow delphinium seed this month for flowers next summer.
Plant outdoors
- Fill gaps in your borders with autumn-flowering plants, such as sedum and Chrysanthemum carinatum 'Polar Star', to extend the colour to the end of the season.
- Plant hyacinth and amaryllis bulbs for forcing, to ensure a crowd of colourful blooms at Christmas. Keep them in a dark, cool place like a shed or garage and bring them indoors when the shoots are 5cm tall. Perfect for a homemade Christmas present!
- Plant spring-flowering bulbs, such as daffodils, crocus and hyacinths.
- Plant out any biennial plants sown earlier in the year. This includes foxgloves, wallflowers and pansy plants.
- Plant new perennials, trees and shrubs. Now is a good time as the soil is still warm and increasing rainfall should be on its way.
Herbs & vegetables to sow and grow
In the cold frame/ greenhouse/ under cloches
- Direct sow spinach now and offer cloche protection as the weather cools. This will ensure harvests throughout autumn and winter.
- Sow spring cabbages, such as 'April' and 'Durham Early' into modules in the greenhouse.
- Sow pak choi ‘Green’ under cloches now for an autumn supply of baby salad leaves.
Direct sow outdoors
- Sow corn salad (lamb's lettuce) now — it’s a fully hardy crop which can be sown outdoors now for cropping throughout the autumn and winter.
- Sow green manure on empty beds now to help improve your soil structure and prevent weeds establishing over winter.
- Sow 'Hi Keeper' onions into a well-prepared seedbed — these are the best variety of onion for autumn sowing. Only thin your onion seedlings in the spring.
- Direct sow salad leaves now for quick crops.
- Try sowing the very hardy 'Perpetual' spinach outdoors this month for winter harvests later in the year.
- Sow winter-hardy spring onions, such as 'White Lisbon' and 'Performer' for crops next spring.
- Make your last direct sowing of summer radish ‘Rainbow Mixed’ this month for autumn cropping.
- Sow turnip seeds into well-prepared beds for small roots.
- Sow winter lettuce, such as 'Arctic King', directly into the ground now.
Plant outdoors
- Start planting garlic sets at the end of the month for cropping next year.
- Plant autumn onion sets this month.
- Plant out any spring cabbages, like ‘Advantage’, sown during the summer.
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