The start of September always seems to take me by surprise. It's the time of year us gardeners get ready for another important growing season: fall. Not only is it time to get seeds and bulbs in the ground for next spring, there are also things to sow for results later in fall and even winter.
That's why here on the Gardens team at Homes & Gardens, we're getting ahead with seeds to order in September. This is an optimal month to get your seed shopping done, so they arrive in time for the planting on your fall gardening checklist. Whether it's spring blooms that benefit from overwintering in the ground, or cool-season crops that should be sown soon for a winter harvest, there are plenty of seeds to get together this month.
A bonus is many of the best flowers to sow in the fall only require purchasing seeds once. By harvesting seeds after they bloom, you'll have more ready for planting this time next year, for free.
7 seeds to order in September
As well as getting these seeds to order in September, don't forget to check out our list of what to plant in September. There is plenty to get in the ground this month, including perennials to plant in September.
1. Calendulas
At the top of Gardens Content Editor Thomas Rutter's list is calendula seeds.
'I will be ordering and sowing my calendula seeds this month. Starting seeds indoors in September or October will result in an earlier flowering period next spring, usually from May to July,' he explains.
There are lots of calendula varieties to choose from, so you can choose a bright orange or yellow daisy-like bloom for your yard.
'I love the 'Indian Prince' calendula variety, which has pale orange blooms that are edible, with a delicious peppery taste,' Thomas says.
'I also have my eye on this 'Apricot Beauty' variety (from Amazon), which had large blooms and sturdy stems, ideal for cut flowers in a vase,' he adds.
Calendulas also make bright additions to a wildflower garden, and you can successfully grow them by sprinkling seeds in a wildflower patch in spring.
Once calendulas stop flowering in late summer, harvest calendula seeds for sowing next fall.
Discover the full range of calendula seeds at True Leaf Market.
Thomas is a Content Editor within the Gardens Team at Homes and Gardens. He has been working as a gardener and garden writer for several years. Whilst completing his Horticultural Traineeship at the Garden Museum, London, he was able to gain experience at many of the UK's world-famous gardens, including Sissinghurst, Lowther Castle, and Iford Manor. Following this, he worked for two private estates in Tuscany, Italy.
2. Nigella
Nigella is one of my favorite spring blooms, especially for a cut flower garden. Just like calendulas, this is one of the seeds to order in September to sow in fall for earlier blooms next spring.
You can grow nigella by planting in spring, but this is likely to give you a later blooming period. By getting ahead and sowing nigella seeds indoors or in a greenhouse in fall, you'll spot nigella seedlings sooner, ready to plant out in spring (after the risk of late frost).
You can then expect to spot blooms as early as May, compared to spring-sown seeds which tend to bloom in June or July.
As cut-and-come-again flowers, you can expect repeat blooms throughout spring and summer with nigella. Just use essential pruning tools (like these pruning snips from Amazon) to harvest them regularly.
Nigella also makes the list of one of the best plants for seedheads, providing fall interest after blooming. Plus, you can collect nigella seeds from the seedpods for next year's sowing.
I personally love the blue varieties of nigella (seeds from Amazon), which provide a pop of color in my flower beds. You can also get a mix of white, blue, and pink nigella seeds (from Amazon).
3. Radishes
It isn't just about flowers when it comes to seeds to order in September, you should also get together your seeds for vegetables to plant in September. One that will give you a fall and winter harvest is radishes.
More specifically, growing radishes in fall requires winter radish varieties; those that are hardier than summer varieties. These Salad Rose Radish Seeds from Burpee are a good option, for example.
As cool-season crops, you can sow your radish seeds directly outdoors in early fall. They tend to grow quickly, so you can expect a harvest in as little as eight weeks.
Unlike summer radishes, you can harvest radishes in fall and early winter as you need them because they're more robust and can stay in the ground for longer. Just make sure to get them out the ground before the harshest winter weather, which can cause them to soften.
Discover the full range of radish seeds at Burpee.
Discover the full range of radish seeds at True Leaf Market.
4. Hollyhocks
This is a seed I left too late to order last year, so I'm getting ahead with it this year. Sowing hollyhock seeds in fall (indoors) allows the plants to develop a robust root system, ready for planting out in spring.
Growing hollyhocks is a rewarding plant to include in your garden, especially for cottage garden schemes. It has tall spires of elegant blooms which can reach five-to-six-feet tall. I plan to add them to the back or my border for some height.
A bonus: hollyhocks are self-seeding flowers, so it's likely they will reappear the following year after flowering, saving you money on having to buy seeds again.
Alternatively, if you want a more controlled approach to growing hollyhocks in your garden again, harvest hollyhock seeds after flowering for replanting.
These stunning blooms come in a wide range of colors. For example, pinks like 'Queeny Purple' (seeds from True Leaf Market) and even blacks like these 'Jet Black' hollyhock seeds from Amazon.
5. Ammi majus
If you love incorporating umbellifer plants to your borders to fill gaps and attract pollinators, Homes & Gardens' UK Editor, Sophia Pouget, suggests ordering Ammi majus seeds this month.
'Ammi majus (seeds from Amazon) is the best white filler foliage plant you can grow and tolerates pretty much any soil type, any weather conditions and bees and butterflies are passionate about it,' says Sophia.
'I sow these plants direct in September and it overwinters marvellously well for an abundance of flowers by late spring. Sowing Ammi in fall makes for much more prolific blooms than if you were to sow it in spring,' she explains.
This is a great flower for a fairy garden plant and it will bloom from June to September, offering interest throughout the summer months.
Sophia Pouget de St Victor is the UK Editor at Homes & Gardens, leading the editorial direction for the UK facing Homes & Gardens website. She brings readers the latest trends, expert insights, and timeless design inspiration tailored for a UK audience.
6. Carrots
Another seed to get your hands on if you're keen to get more out of your kitchen garden before winter: carrots. There's still time to plant carrot seeds for a late harvest.
To grow carrots in early fall, it's best to choose fast-growing, cold-resistant varieties for late season harvests. For example, 'Autumn King' (seeds from Amazon) is a carrot variety favored for planting at this time of year.
For best results, grow carrots undercover in fall. You can either use a greenhouse or these vegetable plant covers (from Amazon) to protect them from frost. If you grow carrots in containers, it's easy to move them under shelter when the frostiest weather comes along.
You should harvest carrots sown in early fall later in the season and early winter, when the carrot shoulder (at surface level) is around an inch in diameter, depending on the variety.
Discover the full range of carrot varieties at Burpee.
Discover the full range of carrot varieties at True Leaf Market.
7. Sweet peas
If you're planning a fragrant garden for your yard next year, now is the time to get your order of sweet pea seeds in. Perfect for cut flowers, filling cottage garden border spots, and even making a sweet pea teepee, this is a versatile bloom to grow in your yard.
'I grow sweet peas every year without having to repurchase seeds,' says Homes & Gardens' Head of Gardens, Rachel Bull. 'It's easy to harvest sweet pea seeds by picking the dried seed pods. These are usually ready by late summer into fall, so I'm harvesting mine in the coming days,' she adds.
There are actually lots of sweet pea varieties to choose from, and by deadheading sweet peas regularly, you'll have a continuous supply of these sweet-smelling flowers throughout spring and summer.
Start sowing sweet pea seeds indoors in fall for earlier blooms in spring.
Discover the full range of sweet pea seeds at True Leaf Market.
Discover the full range of sweet pea seeds at Amazon.
Rachel is a gardening editor, floral designer, flower grower and gardener. Her journalism career began on Country Living magazine, sparking a love of container gardening and wild planting. After more than a decade writing for and editing a range of consumer, business and special interest titles, Rachel became editor of floral art magazine The Flower Arranger. She then trained and worked professionally as a floral designer. She joined the Homes & Gardens team in 2023, where she heads up the Gardens section, and presents the weekly gardening series Petals & Roots.
FAQs
Where can I sow seeds in fall if I don't have a greenhouse?
If you don't have a greenhouse, consider sowing seeds indoors and keeping them on a warm, bright windowsill during the winter months. You can use tools like a heat mat (from Amazon) and even an indoor greenhouse (from Amazon) to aid seed germination, ready for planting out in spring.
With your seeds ordered, you can get started with sowing them. Just make sure to avoid common seed sowing mistakes that could hinder the success of germination.
Shop seed sowing accessories:
These seed starter trays are perfect for sowing seeds in fall, with a greenhouse lid to provide extra warmth and trap in moisture for the seeds to germinate.
Keep track of your sown seeds with these metal plant labels. They're waterproof, so the writing won't wash away, and they can be reused.
Use these seed envelopes to store your harvested seeds. Each envelope has space to note down details, as well as an adhesive strip to secure it.
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