Most people think the garden is winding down in September. They pull up the last of the tomatoes, let the herbs go to seed, and call it a season. But experienced gardeners know something the rest of the neighborhood does not: September is one of the best planting months of the entire year.
Cool-season crops actually prefer the temperatures that September brings. The soil is still warm from summer, which helps seeds germinate quickly, but the air is cooling down in exactly the way that kale, spinach, lettuce, radishes, and carrots love. What you plant this month can be on your table by October and November -- sometimes even later depending on where you live.
This post covers exactly what to get in the ground right now, how long each crop takes to harvest, and closes with a recipe that uses four of these crops together in one pot: a deeply satisfying Autumn Harvest Minestrone that will make you genuinely grateful you kept gardening past Labor Day.
Why September Is a Great Time to Plant
The window feels short but it is more generous than most people realize. Cool-season crops grow fast, tolerate light frost, and in many cases taste better after a cold snap -- the chill converts starches to sugars, which is why fall kale and carrots are noticeably sweeter than their summer counterparts.
- Check your first frost date. In most of the northeastern and mid-Atlantic US, the first frost falls somewhere between mid-October and early November. That gives you 6 to 8 weeks of solid growing time from a September planting.
- Focus on fast-maturing varieties. Days to maturity matters more in September than any other month. Stick to varieties that finish in 30 to 60 days.
- Plant in a sunny spot. Days are getting shorter, so give your fall crops the sunniest location in your garden to compensate.
- Water consistently after planting. Germination is fast in warm September soil, but seedlings need steady moisture in their first two weeks.
What to Plant in September
Kale — Days to harvest: 50 to 65 days
Kale is one of the most cold-hardy vegetables you can grow. It handles frost without flinching and many gardeners find that a light freeze actually improves the flavor. Plant now and you can be harvesting well into November in most climates. It is also one of the most productive crops per square foot you can grow -- one plant keeps producing leaves for weeks. Use it in soups, salads, sauteed as a side dish, or blended into a pesto. It is the backbone of the Minestrone recipe below. Shop kale seeds.
Spinach — Days to harvest: 40 to 50 days
Spinach is one of the fastest cool-season crops and one of the most cold-tolerant. It can survive temperatures down to the mid-20s with a little protection and will keep producing cut-and-come-again leaves right up until a hard freeze. September-planted spinach often produces a second flush of growth in early spring if it overwinters successfully. Use it fresh in salads, wilted into pasta, or stirred into soups and eggs. Shop Spinach, Bloomsdale Savoy seeds.
Lettuce — Days to harvest: 45 to 60 days
Lettuce bolts in summer heat but absolutely thrives in cool fall weather. September-planted lettuce grows slowly and evenly, producing tender, flavorful leaves that are noticeably better than anything you can grow in July. It does not tolerate a hard freeze, so plan to harvest before temperatures consistently drop below 28°F or cover with a row cover to extend the season. Shop lettuce varieties.
Radishes — Days to harvest: 22 to 30 days
Radishes are the fastest crop in the fall garden and a great choice if you are nervous about the window. You can plant them in mid-September and have something to eat by mid-October. They are also a good companion for slower crops -- plant them between rows of carrots and kale to make use of every inch of space. Try them raw with butter and salt, quick-pickled, thinly sliced into salads, or roasted until sweet and tender. Shop radish seeds.
Carrots — Days to harvest: 60 to 75 days
Carrots are the most patient crop on this list and the most rewarding. They need the full window, so get them in the ground in the first week of September for the best results. Like kale, their flavor improves significantly after a frost. They also store incredibly well right in the ground, which means you can leave them and harvest as needed well into late fall. Shop Carrot, Danvers Half Long seeds.
Quick Planting Tips
- Kale: Direct sow or transplant. Space plants 12 to 18 inches apart. Thin seedlings when they reach 3 inches tall.
- Spinach: Direct sow in rows, about half an inch deep. Thin to 3 to 4 inches apart once sprouted. Succession plant every two weeks for a longer harvest.
- Lettuce: Scatter seeds lightly and press into the soil. Does not need to be buried deep -- lettuce needs light to germinate. Keep soil consistently moist until seedlings appear.
- Radishes: Direct sow half an inch deep, one inch apart. Thin to 2 inches once sprouted. Do not let them stay in the ground past maturity or they turn woody.
- Carrots: Direct sow in loose, well-worked soil. Thin to 3 inches apart once seedlings are 2 inches tall. Carrots need loose soil to form straight roots -- break up any clumps before planting.
Recipe of the Month: Autumn Harvest Minestrone
Extending Your Fall Garden Season
- Row covers and frost cloth: A lightweight row cover can protect your crops from frost and extend your harvest by three to four weeks in most climates.
- Cold frames: A simple cold frame built from an old window and four boards can keep lettuce, spinach, and kale producing well into December in many parts of the country.
- Succession planting: Do not plant everything at once. Stagger your lettuce, spinach, and radish plantings by two weeks to keep a steady harvest coming.
- Mulch heavily: Once temperatures start dropping consistently, a layer of straw or shredded leaves around your plants helps insulate the soil and protect roots.
September gardening is one of the quieter pleasures of the growing season. The summer rush is over, the garden is not yet put to bed, and there is something genuinely satisfying about putting seeds in the ground when the rest of the neighborhood has stopped paying attention to theirs. The harvest that follows -- sweet fall carrots, tender kale after the first frost, crisp October lettuce -- is some of the best eating of the whole year.
Get those seeds in the ground this month. Your October self will be very glad you did.