What Can You Plant in September? 15 Seeds That Thrive in Cooler Weather

Can you plant from seed in September?

Of course! But where you live will determine what makes the most sense for you.

This year, at the end of August, my beans were done, and I was ready for some fresh greens. In September, I planted seeds for lettuce, kale, and radish.

It may seem too late to plant seeds, but even though we could have a frost in October, there are plenty of fast-growing crops. I can also use a frost blanket to cover my garden on those cold nights.

Often, the first frost is followed by warm days where the greens will continue to grow. Kale is one of those hardy greens that will continue growing even when temperatures dip into the 20s. September is the right time to plant kale and other cold-hardy greens like tat soi.

To play it safe in cooler climates where the first frost is fast approaching, focus on growing plants that don’t form a head.

These leafy vegetables will grow quickly and be ready to harvest as the weather grows cooler.

In most locations, you can plant these seeds in September:

• Spinach
• Lettuce
• Radishes
• Kale
• Arugula
• Swiss Chard
• Mustard Greens
• Tat Soi
• Bok Choy

In cooler climates, use row covers or frost blankets to extend the season. You can also use mulch to keep the ground warm.

• Cilantro - Quick growing and can be harvested in about 3 weeks.
• Chervil - Seeds germinate in cooler soil temperatures, ranging from 50 to 65°F.
• Lovage - The leaves will die back in winter, but the roots are cold hardy to -5ºF. New growth will appear when the weather warms up in spring.
• Sorrel - You can also plant sorrel in the fall. The leaves will die back after a hard frost, but the roots can survive in temperatures as cold as -20ºF.

In any location, you can plant cover crops as part of your rotation before the next growing season. 

Buckwheat grows quickly, germinating in as little as three days. It will add nutrients and organic matter to the soil.

Winter oats are quick growing and can mature in 40 to 60 days.

Winter rye is cold hardy and can grow through the winter.

You can use cover crops to amend clay soil and create a better garden. Plant the best cover crops for your garden.

In zones where there is still a long time before a frost, you can grow more than leafy greens. With mild winters, you can plant Kohlrabi, carrots, broccoli, cauliflower, and Swiss chard.

Cucumber seeds can be planted in the warmest zones, such as Florida. You can plant beans, squash, and even tomatoes in September.

And don’t forget about onions. Short-day onions, such as our Texas Early Grano and Red Creole, are ideal for planting in September.

It’s easy to get garden burnout at the end of summer. Especially if it’s been too hot to keep up with maintenance. But even if you tear out everything in complete frustration, you can start over with these leafy greens, herbs, and cover crops.

Take advantage of the change in season when temperatures are less extreme and there are fewer pests. At our Sow Right Seeds garden, we are planting cole crops in our high tunnel. With this added protection, we will still be harvesting into December. 

Whatever you do, don’t leave your soil bare. September is the perfect month to plant cover crops, and they’ll replenish your soil, creating a better garden next season.