September is one of the most rewarding months in the garden calendar. The soil is still warm from summer, rainfall becomes more reliable, and cooler air temperatures create ideal growing conditions for a wide range of crops and ornamentals. Whether you are tending a kitchen garden, a balcony, or a sprawling plot, knowing what to plant in September – or, as many French gardeners ask, que planter en septembre – gives you a real head start on next spring and even extends your harvest well into winter.
This guide covers vegetables, flowers, bulbs, and herbs, with practical advice adapted to different climates.
Que planter en septembre – What to Plant in September (Full Autumn Guide)
Reading time: ~11 min
- Why September Is a Strategic Planting Month
- Vegetables to Plant in September
- Flowers to Sow and Plant in September
- Bulbs to Plant in September for Spring
- Herbs to Sow in September
- Climate-Specific Planting Guide for September
- Perennials, Shrubs, and Fruit Bushes
- Practical Tips for September Planting
- Frequently Asked Questions
- Making the Most of Your September Garden
Why September Is a Strategic Planting Month
Many gardeners mistakenly treat September as the end of the growing season. In reality, it marks the beginning of a new cycle. According to hardy annuals sown in September blooming a couple of weeks earlier than the same varieties sown in spring, this month rewards gardeners who plan ahead rather than pack away their tools.
Overwintering vegetables planted now will establish strong root systems before the cold sets in, delivering earlier and more abundant harvests the following year. The combination of warm soil and decreasing temperatures also makes September one of the best times to plant perennials, shrubs, and spring-flowering bulbs. For a broader seasonal overview, our September gardening guide covers the wider list of garden jobs for the month.
Vegetables to Plant in September
September is the month of the cool-season kitchen garden. A wide range of vegetables can be sown or transplanted now, depending on your climate and the level of protection you can offer.
Overwintering vegetables to plant in September
Overwintering staples are among the most valuable crops to get in the ground this month. Garlic is a top priority: plant individual cloves now for a mid-summer harvest the following year. Overwintering or Japanese onion sets can go in now and will be ready to harvest before summer varieties. Shallots follow the same logic. Spring cabbages and purple sprouting broccoli should be transplanted as young plants in early September so they can establish before the coldest weeks arrive. Broad beans sown in September will overwinter as small plants and crop earlier in spring than those sown in February or March.
Leafy greens and salad crops are equally important for September sowing. Winter lettuces, spinach, Swiss chard, mizuna, pak choi, mustard leaves, and tatsoi all thrive in cooler conditions and can be harvested through winter with minimal protection such as a cloche or cold frame. The University of Arkansas Cooperative Extension Service also recommends kale and turnip greens as reliable September sowings in temperate regions.
Root crops round out the September vegetable calendar. Carrots dislike heat and grow better in cooler months, making them excellent candidates for a September sowing in areas with mild autumns. Beets, radishes, and turnips can also be sown now for a late-season harvest.
If you are gardening in a cold climate, using a polytunnel, cold frame, or fleece over your September sowings can extend the harvest of salad leaves and greens by several weeks, often right through to February.
Flowers to Sow and Plant in September
September is excellent for both sowing hardy annuals and planting ornamentals that will provide colour through autumn and into winter.
Hardy annual flowers for September sowing
Hardy annuals sown directly into prepared soil this month will overwinter as small plants and flower earlier next year than spring-sown equivalents. Pot marigold (Calendula officinalis) and love-in-a-mist (Nigella damascena) are classic examples. Cornflowers, poppies, Limnanthes (the poached egg plant), and Scabiosa can also be sown outdoors throughout September in temperate climates. These plants are frost-tolerant once established and need very little intervention over winter.
For immediate autumn colour, asters, cosmos, pansies, snapdragons, and dianthus can be planted out now. Ornamental cabbages and kales add structural interest to borders and containers through the colder months. These are particularly useful for gardeners who want visual impact while their overwintering crops are getting established.
Bulbs to Plant in September for Spring
Planting spring-flowering bulbs is one of the most satisfying September tasks. The ground is still warm enough for good root establishment before dormancy sets in, which means bulbs planted now will produce stronger flowers in spring than those planted late.
Best bulbs to plant in September
Narcissus (daffodils) should be among the first bulbs in the ground in September. September is ideal for planting swathes of narcissi, alliums, and muscari, while tulips are better left until the soil has cooled further, typically in October or November. Other bulbs suited to September planting include:
- Crocus, snowdrops, and hyacinths
- Irises and fritillaries
- Scillas, bluebells, and anemones
Planting a mix of early, mid, and late-flowering varieties ensures a succession of colour from late winter through to late spring. For naturalising bulbs in grass or under trees, September is the optimal window. Once planted, these bulbs require almost no maintenance and will multiply year after year, supporting pollinators and increasing biodiversity in your garden.
Herbs to Sow in September
Several herbs can be sown outdoors in September, particularly those that prefer cooler growing conditions. Coriander (cilantro) and dill both tend to bolt in summer heat, so a September sowing often produces better results than a spring one. Parsley can also be sown now, though germination is slow and seedlings will benefit from the protection of a cloche as temperatures drop.
Perennial herbs such as thyme, sage, and chives are best planted in early autumn when the soil is still warm, giving roots time to establish before winter. If you are working with limited space, our balcony herb planter guide offers practical layout ideas for growing herbs in containers.
Climate-Specific Planting Guide for September
What to plant in September varies significantly depending on where you garden. The table below provides a practical overview across four broad climate types.
| Climate type | Vegetables to sow or plant | Flowers and herbs | Key consideration |
|---|---|---|---|
| Cold (continental, mountain) | Bunching onions, lettuce, radish, spinach, carrots, kale | Calendula, cilantro, dill | Use cloches or cold frames; focus on fast-maturing varieties |
| Temperate (UK, Northern France, Northern US) | Garlic, onion sets, broad beans, spring cabbage, lettuce, spinach, Swiss chard, carrots, beets | Hardy annuals (Nigella, Calendula, cornflowers), spring bulbs | Ideal window for overwintering crops and bulb planting |
| Mild (Mediterranean, Southern UK, Pacific coast) | Carrots, lettuce, radish, spinach, sugar snap peas, bush beans, short-season cucumbers | Asters, cosmos, pansies, parsley | Longer window; succession sowing possible into October |
| Hot (Southern US, North Africa, warm coastal areas) | Dill, kale, lettuce, parsley, Swiss chard, potatoes | Calendula, snapdragons, dianthus | September marks the start of the main growing season as summer heat eases |
Perennials, Shrubs, and Fruit Bushes
September is widely considered one of the best times to plant perennials, shrubs, and even trees. The soil retains summer warmth while autumn rain reduces the need for irrigation, giving new plants the best possible start. Ornamental grasses planted now establish quickly and provide structure through winter.
Fruit bushes, including raspberry canes, blackcurrants, and gooseberries, can go in from September onwards as they begin to go dormant. Mixing early, mid, and late varieties of raspberries ensures a staggered harvest the following summer.
At SeedsWild, we offer a selection of open-pollinated and organic seeds suited to autumn sowing, including varieties chosen for their hardiness and adaptability to different European climates. You can explore the full range on the SeedsWild shop and use the AI-powered recommendation tool to find the varieties best suited to your location and growing conditions.
Practical Tips for September Planting
Soil preparation for September planting
Good soil preparation makes a significant difference to the success of September plantings. Incorporate well-rotted compost before sowing or planting to improve both drainage and moisture retention. For overwintering crops, check that your beds are clear of summer debris and that you follow a sound crop rotation plan: avoid planting brassicas where brassicas grew last year, and the same applies to alliums and root crops.
Frost protection is worth planning ahead. Even in temperate climates, an early frost can damage young seedlings. Keep cloches, horticultural fleece, and cold frames ready to deploy at short notice. Sowing depth and plant spacing matter too: follow the guidance on each seed packet, as overcrowded seedlings are more vulnerable to disease and will need thinning to perform well.
For bulbs, the general rule is to plant at a depth of roughly two to three times the diameter of the bulb. Good drainage is essential: bulbs sitting in waterlogged soil over winter are likely to rot before they can flower.
September plantings benefit from the combination of warm soil and cooler air. This is the key to strong root establishment for overwintering crops and spring bulbs alike. Acting early in the month gives seedlings the longest possible window before the shortest days arrive.
Frequently Asked Questions
Is it too late to plant garlic in September?
No, September is actually one of the best times to plant garlic in temperate climates. Cloves planted in September have time to develop a good root system before winter and will be ready to harvest by mid-summer the following year. In very cold climates, planting in early September rather than late in the month gives the cloves a better start.
Can I grow salad leaves through winter if I sow them in September?
Yes, many salad crops sown in September will continue to produce leaves through winter, especially with some protection. Winter lettuces, spinach, mizuna, tatsoi, and Swiss chard are all hardy enough to survive light frosts. A cold frame, cloche, or layer of horticultural fleece will significantly extend the harvest period and protect against harder frosts.
Which spring bulbs should I plant in September and which should I wait on?
Narcissi, alliums, muscari, crocus, snowdrops, hyacinths, scillas, and anemones are all well suited to September planting. Tulips are the main exception: they perform better when planted in colder soil, typically from late October onwards, as this reduces the risk of tulip fire disease and encourages stronger flowering.
Can I plant herbs outdoors in September?
Several herbs can be sown outdoors in September with good results. Coriander and dill are particularly well suited to autumn sowing because they tend to bolt in summer heat. Parsley can also be sown now, though it germinates slowly and benefits from cloche protection as temperatures drop. Perennial herbs like thyme and sage are best planted out in early September to allow root establishment before winter.
How do I protect September plantings from early frost?
The most effective and accessible forms of protection are horticultural fleece, cloches, and cold frames. Fleece can be draped directly over plants or seedlings and held in place with pegs or soil at the edges. Cloches work well for individual rows of seedlings. A cold frame provides more robust protection for tender or young plants and can be ventilated during mild days to prevent overheating. Mulching around the base of newly planted perennials and shrubs also helps insulate roots from temperature extremes.
Making the Most of Your September Garden
September rewards gardeners who plan ahead. By sowing cool-season vegetables, planting spring bulbs, getting hardy annuals into the ground, and establishing perennials and fruit bushes, you are setting up your garden for a productive winter and a spectacular spring. The decisions made in September often determine the quality of the harvest and the beauty of the garden in the months that follow.
Whether you are working with a large plot or a few containers on a balcony, there is something meaningful to plant this month. Once your September tasks are complete, you can start looking ahead to what to plant in October to keep the momentum going into the colder months.
