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What to Plant in September | Almanac.com

What to Plant in September

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You must sow these vegetable seeds in September

Think the sowing season’s over? Think again! Find out which vegetables to sow in September to keep your garden productive for longer!

It’s tempting to just enjoy the harvests but making extra sowings now will set you up for even more crops later on this autumn, through winter, and on into spring. And what are they? Well let’s find out!

Vegetables to Sow in September

1. Asian Greens

What better place to start than with a tempting array of Asian greens. Haven’t heard of them? Don’t worry – they’re simple to grow! And they promise a wide range of spicy tones and pleasing textures sure to bring winter salads and stir-fries to rousing life!

  1. Mizuna leaves have a delightfully delicate spice to them a bit like arugula. 
  2. Mibuna, which is a close relative of mizuna, is another delightful green, producing long, almost spoon-shaped leaves with a mild, mustard taste. 
  3. Komatsuna, also called mustard spinach, produces loose clusters of leaves that look a little bit like bok choi or pak choi, just much smaller. The leaves have a mild flavor maturing to a more peppery tang as the leaves get older. 
  4. Mustard, of course, is my go-to winter favorite. Mustards come in an astounding range of leaf shapes and colors – there are so many unique varieties to explore. I’ve gone for this more rounded, red variety, which will give a bit of a visual contrast to the others. And with that also labelled I can now just cover all our seeds with some more potting mix, just so they’re snug out of sight.

The great thing about these leafy lovelies is that they really don’t mind being sown at a much cooler point in the growing season; they’ll grow quickly to give some useable leaves over the next few months. Try growing through the winter with some protection, and they’ll grow again in early spring.

  • You can sow these seeds right into the ground around the time tomatoes finish up. See fall planting dates for arugula.
  • Or, you can sow seeds in plug trays; each square if filled with potting soil. Then I just sow about 4 seeds into each plug or cell. Then let the seeds grow on for about a month in a greenhouse or in a shady place outdoors (with a row cover). By that time, the tomatoes and cucumbers finish.
  • It’s really important to give them plenty of space to soak up sunlight as autumn advances, so I’ll space each plug quite widely, about 9 inches or 22 cm apart.

If you have a greenhouse, you can keep growing these Asian greens through the winter. See this video to learn more.

Learn more about 7 fast-growing Asian greens to grow in the fall.

2. Winter Salad Leaves

Winter salad leaves are hardy enough to grow out in the open, though you will get a more reliable harvest if you cover them with something like a miniature hoop house. I’ve chosen three of the very hardiest winter salads, capable of withstanding winter’s chill!

Sow into a bed that gets a fair amount of direct sunshine. To prepare it for sowing, sprinkle on some balanced organic fertilizer; I’ve gone for blood, fish and bone. Now it’s just a question of raking it level to leave a fine, crumbly texture to sow into.

  1. Mache, also known as corn salad or lamb’s lettuce, produces these soft and tender leaves, but don’t be fooled by that – it’s remarkably hardy! With an almost creamy texture and light, nutty taste, this is the perfect choice to counterbalance some of the spicier tones of those Asian greens.
    • Mache is easy to sow in rows, so let’s mark out shallow drills – let’s go for two, about 8 inches or 20 cm apart. And to sow, just take a pinch of seeds and sow nice and thinly into the row before pinching back just enough soil to cover the seeds over – no more than about a quarter inch or half centimeter. Once the seedlings are up, I will thin them out to leave just one plant every couple of inches or 5 cm or so.
  2. Cress is a winter salad green that looks like watercress and tastes similar, too, making it an excellent, hardy alternative. I’m going to sow a couple of rows into two more shallow drills, this time a foot or 30 cm apart. And again, it’s in with the seeds nice and thinly spread, and these will be thinned on germination to around 4 to 6 inches or 10 to 15 cm apart within the rows
  3. Claytonia, also known as winter purslane or miner’s lettuce, produces soft, almost waxy heart-shaped leaves – how lovely! And when the tiny, ever-so-delicate white flowers appear in spring – you can eat those too. It loves the cool, damp conditions of autumn and, if you let it, will naturally self-seed, giving you an almost perennial patch of this accommodating leaf. Sow it into shallow drills spaced 8 inches or 20 cm apart, then thin to around 3 inches or 7 cm apart once they’re up.

Keep your winter salads weed-free to help improve airflow and light levels around your plants, while giving slugs fewer places to lurk. They should all give something to harvest this autumn and, after a brief slowdown in winter, will pick up growth again by spring. They’re hardy, but as I mentioned earlier, you can coax more harvests from them if you cover them from mid to late autumn. I use both miniature hoop houses and temporary cold frames for this purpose, and if you’d like to know how easy it is to set them up, check out our video on season extenders here.

Learn more about how to grow four super-hardy salad greens to grow in winter.

3. Root Vegetables

There’s still time to sow a few tasty roots to harvest this side of winter, and I’ve got two speedy growers that should do well as summer’s heat starts to wane: fast-growing radish and baby turnip.

For radish: I’m going for my favorite, white-tipped ‘French Breakfast’.  I can think of no better way to wake up the palate than with this crisp, gently warming root. Lovely stuff. They’re going in at about a half inch or 1 cm deep and, as the seeds are easy to handle, I’m doing my best to drop just one seed every half inch or centimeter. The soil is warm at this time of year so these will germinate quickly and, in fact, sowing now is a smart move as there are far fewer flea beetles about this late in the season. We should get something to lift within about four to six weeks, depending on the weather.

For turnips: which I’m sowing not for large, full-sized roots but more dainty baby roots, not much bigger than our radishes, perhaps up to about golf ball size. These should be ready to harvest in around six to eight weeks. Sowing’s the same as for radish, although if I get good germination then I may need to remove some of the seedlings so that I’m left with about 2 to 3 inches, that’s 5 to 7 cm between each plant. Any excess seedlings won’t be wasted – I’ll add them to a salad. In fact, turnip leaves – or ‘turnip tops’ – at any stage make fab eating as a bonus extra green… and as I’ve said many times before, we need more greens in our lives!

Beets can also be grown if you’re going to be growing them under the protection of a greenhouse or hoop house, or outdoors if you’re in a warmer climate. We’ll be sowing and growing beets in our next video when I look forward to shining a light on this veggie garden staple and how to get the best from it.

4. Spring Cabbages

We’re pushing it a bit with cabbages, but if you get on and sow spring cabbages early in the month there should be enough time to plant them in a few weeks, ready for some of earliest leafy greens next spring – perfect for filling what gardeners know as the ‘hungry gap’, when pickings are notoriously on the lean side.

I’m sowing them into plug trays of our sieved all-purpose potting mix and this time I’m just sowing a couple of seeds into each. If both germinate, I’ll remove the smallest seedlings to leave just one in each plug to grow on. Then, perhaps another three weeks on from that point, they’ll be big enough to go outside, spaced around 10 inches or 25 cm apart for plenty of leaves, or a little more than that for full-sized, densely-packed hearts. I won’t have to worry about caterpillar damage by then, though I will be covering them later in the autumn the moment the pigeons start to show an interest!

If you’d like to know more about keeping pests off your cabbages, see how to keep bugs off brassicas here! In the meantime, happy sowing and growing!

About The Author

Benedict Vanheems

Benedict Vanheems is the author of GrowVeg and a lifelong gardener with a BSc and an RHS General Certificate in horticulture. Read More from Benedict Vanheems

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