September is a busy time in the garden. Borders are full of late-flowering perennials and harvest is in full swing. As you gather your crops, make the most of any empty spaces to sow winter vegetables, such as turnips, endive and winter purslane.
Hardy annuals can also be started off any time in the next few weeks for colourful displays next summer. Sowing in autumn, rather than spring, produces vigorous plants that flower earlier, and you’ll benefit from fewer jobs to do in the garden next year.
More seed sowing inspiration:
Vegetables and Herbs
Picking leaves from American land cress
A biennial winter salad leaf with a spicy taste similar to watercress, land cress is easier to grow as it prefers moist conditions but doesn’t need running water. Direct sow into moisture-retentive soil in beds or containers in full sun or partial shade. Lightly cover seeds and thin seedlings to 15cm. Don’t waste the thinnings – they make great microveg leaves. Make sure you label rows to avoid accidentally pulling out your crop as land cress seedlings resemble many other common weeds.
You can sow successionally every three-four weeks, until the end of October. Leaves can be harvested as a cut-and-come-again crop from late autumn until spring. Protecting plants with cloches or fleece in winter (which also has the advantage of preventing pigeons eating the leaves) will ensure a better harvest. Bring container-grown plants into a greenhouse when the weather gets cold.
Sow endive seeds now for cut-and-come-again salad leaves
This relative of chicory has been grown in the UK since the mid-sixteenth century. Gervase Markham mentions endive in The English Housewife in 1615, and Isabella Beeton notes it is grown ‘in abundance’ in London in the 1860s.
Although endive is usually sown at the end of summer for winter crops, you can still sow early in September if the soil is warm, or any time during the month for cut-and-come-again salad leaves. Sow seeds in containers or in situ in light, free-draining soil. Thin plants to 30cm. Baby salad leaves should be ready for harvesting about five weeks after sowing. Choose broad-leaf hardier varieties (rather than curled endive) for winter cropping like ‘Wallone’, ‘Green Batavian’ and ‘Natacha’.
The vegetable plot is full of ripe seed this month, providing money-saving opportunities every time you harvest. Peas, beans and radishes are among the easiest seeds to gather. Leave pea and bean pods on the plant until completely dry. Then pick pods, remove seeds and store in labelled envelopes. Radishes can be left to go to flower and seeds collected once they have dried. In wet weather, seeds can be harvested early and dried indoors.
Thinning dill seedlings
Whether you grow this versatile herb to add flavour to soups, salads and fish dishes, to use the seeds for pickling, or to add its ferny foliage to bouquets of flowers, it prefers to grow in moist soil in a sunny, sheltered spot. Dill is also a fantastic addition to any wildlife border as the flowerheads are rich in pollen and nectar, which attracts a range of pollinating insects.
The main sowing season for dill runs from spring to mid-summer, but it’s worth a repeat sowing this month to provide leaves over winter. Sow dill seeds in large pots or in situ as transplanting seedlings causes plants to flower prematurely. Dill looks rather like a smaller version of fennel, but the two should not be grown close together as they have a tendency to hybridise, which can affect the flavour. Compact ‘Bouquet’ is ideal in containers as it only reaches 30cm in height, whereas ‘Mammoth’ can grow up to 1.5m! ‘Tetra’ has bushy dark green foliage and is slow to bolt, which makes it perfect for sowing during the warmer months.
Sweet cicely plant growing in pot
Another attractive umbel, sweet cicely has white flowerheads in spring and early summer, and divided foliage with an aniseed flavour. Also known as garden myrrh or the Roman plant, this aromatic herb is a traditional cottage garden favourite, best known for being cooked with rhubarb and tart fruits to reduce their acidity.
It prefers a spot in partial shade and was often grown outside the backdoor of cottages to allow easy access from the kitchen. Sow seeds in autumn (or spring) in rich, moist soil. If grown for foliage, remove flower stalks and cut plants back in the growing season to encourage a fresh flush of leaves.
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Snapdragon ‘Appleblossom’ has subtle pink flowers
Many people have fond childhood memories of these charismatic flowers with their flamboyant colours and miniature dragon mouths that roar when you squeeze their throats. I love to grow stately white snapdragons like Antirrhinum ‘Royal Bride’ and the striking two-tone A. ‘Night and Day’ with its gorgeous crimson and white flowers. For more subtle shades, try the soft pinks of A. ‘Appleblossom’ and double ivory blooms of A. ‘Madam Butterfly’.
Sow snapdragon seeds thinly in peat-free compost in trays or modules. Water gently, but do not cover seed. Place on a sunny windowsill in a propagator or inside a large clear plastic bag. Prick out seedlings once they are large enough to handle and grow on in a greenhouse or cold frame. Plant out in spring after the last frost. Although snapdragons are usually grown as half-hardy annuals, they are actually short-lived perennials and, as our winters warm, they are overwintering more often in the UK. So if you raise some from seed now, it might be a few years before you’ll need to sow snapdragons again.
Grow Nigella damascena with other hardy annuals for a colourful summer display
Love-in-a-mist looks wonderful planted along the front of borders in drifts. Mine self-sow every year and I save seeds too, so it’s easy to spread the love around the garden. Sow direct, cover with a fine layer of soil and thin seedlings to 10-15cm apart.
The traditional hazy blue, pink and white mix (Nigella ‘Persian Jewels’) is a must-have in our garden. We also grow N. papillosa ‘Delft Blue’ which has white flowers with navy markings and glorious burgundy seedpods. N. damascena ‘Albion White Pod’ is another striking variety with its snowy white petals and bright green seedpods.
Poached egg plant
Poached egg plant is great for ground cover and will attract an array of insects
When I first came across these cheerful yellow and white hardy annuals sprawling though a kitchen garden, the whole area was alive with hoverflies and bees. With vivid yellow ‘yolks’ in the centre of the flowers and a white band around the edge of the petals, poached egg plants (Limnanthes douglasii) are fun to grow with kids and such an easy way to entice pollinating insects into the garden.
Prepare the ground by weeding and raking an area of well-drained soil in full sun. Scatter seeds for a naturalistic look or sow in rows, which makes it easier to weed once seedlings begin to emerge. Cover with a thin layer of soil and water well using a watering can with a fine rose. It really is as easy as that! By next June you’ll be enjoying an eye-catching display and your garden will be full of the sounds of busy insects.
Greater quaking grass
Grow beautiful greater quaking grass in groups for maximum impact
Briza maxima is a stalwart in our garden, forming an airy backdrop in many of our ornamental container displays. A relative of wild quaking grass (Briza media), it has the most beautiful pale green spikelets that dangle from thin grass stems and dry to a light biscuit-brown as the year progresses.
Sow seeds this month in well-drained soil in a sunny spot and cover with a fine layer of soil. Germination will occur next spring and by June you should have a profusion of this elegant grass in your pots and borders. Ours self-seeds prolifically around the garden, but unwanted seedlings are easy to remove.
Bishop’s flower ( Ammi majus)
Ammi majus and Ammi visnaga can both be sown this month to produce delightful umbels of white flowers next summer. Ammi majus has delicate flowerheads rather like cow parsley, whereas Ammi visnaga has denser umbels. Both make wonderful fillers for cut flower arrangements.
Sow seeds under cover and plant out in spring in full sun, spacing plants 60cm apart.
Other umbellifers which can be sown now include ornamental carrot (Daucus carota ‘Dara’) and forms of cow parsley, such as Anthriscus sylvestris ‘Ravenswing’ which has deep purple, almost black, foliage and stems. Both should be sown direct and need cold weather to germinate, so autumn is the ideal time to sow.
Why not create pockets of perennial meadow in your garden to provide food plants for a range of insects? Perennial meadows are sustainable habitats because as well as being a haven for wildlife, once they are established, they need little maintenance apart from a yearly cut.
Mid-September to the end of October is the best time to sow, although a spring sowing is better for heavy soils, and meadow mixes are available for many soil types. Choose an open sunny site free of perennial weeds with unproductive soil where wildflowers will not be outcompeted by vigorous grasses. If you have fertile soil, remove the top 5cm and reuse elsewhere in the garden. Rake the ground to create a fine tilth and sow your seed mix.
Other seeds to sow in September:
- Vegetables: spinach, broad beans, peas, radish, turnip, onions, garlic, winter purslane, pak choi
- Flowers: calendula, cornflower, poppy, Californian poppy, violas, lupins