Garden of Eatin' / Vegetables

10 Fast-Growing Vegetables You Can Harvest in 40 Days or Less

Fast-growing vegetables you can grow in 40 days or less

If your garden is flush with ripe juicy tomatoes right now, it’s hard to believe the clock is ticking quickly toward the first frost of fall. And if you haven’t planned for fall planting yet, your options are much more limited now than they are earlier in the season.

Luckily, there are still many crops that can be planted and harvested ahead of the first freeze in your garden.

Knowing what grows fast—and planting them now—is also a better option than watching your summer vegetables struggle to ripen the last few fruits. Those heat-loving plants will start to wind down and produce less and less with each diminishing day of light, so it’s a good time to pull them out and put in crops that thrive in cooler weather.

Besides, all of these crops actually do better when they’re allowed to mature in fall and winter, as they’re naturally programmed to turn sweeter after a few frosts.

So if you’ve ever wondered, “What can I plant right now this late in the season?” this guide can help you choose reliable, unfussy, and easy-to-grow crops for the waning summer days.

Here are my top picks for fast-growing fall vegetables that mature in 40 days or less.

Why 40? Because few vegetables are ready for picking in fewer days than this, but it’s still a short enough period (a little over a month) that it’s easy to plan for and execute this time of year.

Consider this your last call for planting and sneak in just a few more harvests before you put your garden to bed for winter.

Disclosure: All products on this page are independently selected. If you buy from one of my links, I may earn a commission.
Bundle of French breakfast radishes on a rustic wooden surface

1. Radishes

Seed to harvest: 20 to 25 days

The same radishes you planted in spring also do well in late summer and early fall, and they’re always one of the first crops to germinate and mature in the garden, giving you near-instant gratification. Succession sow the seeds and you can get at least two harvests before frost.

Radishes are ready for harvest once they reach about 1 inch in diameter. Don’t toss the greens—those are edible too.

Favorite varieties: French Breakfast, Cherry Belle, Easter Egg Blend, Crimson Giant

Bunch of red baby beets on a rustic wooden surface

2. Baby beets

Seed to harvest: 40 days

Miniature beet varieties (like Babybeat and Baby Ball) are perfectly round and ready for harvest in 40 days. At full size they measure just 1 to 2 inches in diameter, but truth is, any beet can be harvested in the baby stage.

When you pick a beet early, you also get the bonus of beet greens, which are so tender when young that you can eat them raw in salads. (You can also roast and pickle beets whole!)

Favorite varieties: Babybeat, Baby Ball, Chioggia, Golden Boy

Bundle of baby white turnips tied together

3. Turnips

Seed to harvest: 30 to 40 days

As one of the most reliable fall crops, turnips can be harvested at any stage of growth. When they’re young, turnips (both the roots and the greens) are actually milder and sweeter, so they’re a good way to go if you find mature turnips too bitter.

Pick them once they reach 1 to 1 1/2 inches in diameter and try them pickled, sauteed, or roasted.

Favorite varieties: Purple Top White Globe, Market Express, Golden Ball, White Egg

Purple kohlrabi growing in a garden

4. Kohlrabi

Seed to harvest: 40 days

Many people shy away from kohlrabi because it looks so strange, but it’s a versatile vegetable that starts off sort of peppery when raw, and mellows into a smooth, mild flavor when cooked.

Kohlrabi typically takes 50 days to mature, but you can pull it earlier without sacrificing too much in size. The bulbs and leaves are all edible, so you get a double harvest before the season’s over. Be sure to plant kohlrabi that’s meant for fresh eating (and not storage kohlrabi).

Favorite varieties: White Vienna, Purple Vienna, Konan, Blauer Speck

Young spinach plants growing in a garden with drip tape irrigation

5. Spinach

Seed to harvest: 30 to 40 days

Spinach is a cold-hardy green that makes a great cut-and-come-again crop. Just snip a few outer leaves from each plant and let them continue growing until, well… you’re sick of eating spinach! This frost-loving vegetable can survive down to 20°F, so it’s an excellent choice if you want to keep harvesting salads in winter.

Spinach seeds won’t germinate if soil temps are over 75°F, so use a soil thermometer like this one to figure out the best time to plant.

Favorite varieties: Bloomsdale, Matador, Lavewa, Noble Giant

Red and green baby lettuce plants growing in a cold frame

6. Lettuce

Seed to harvest: 21 to 30 days

If succession planted, lettuce can provide at least two harvests before frost sets in (as long as you have a minimum of 40 days before your first freeze).

It grows easily in late summer and early fall conditions, but struggles to germinate if soil temperatures are over 80°F. So if there’s a late-season heat spell, you may be better off starting seeds indoors and transplanting when the weather’s cooler.

Favorite varieties: Salad Bowl Blend, Gourmet Baby Greens Mix, Chef’s Choice Mesclun Mix, Black Seeded Simpson

Close-up of baby arugula piled on a cutting board with a knife

7. Arugula

Seed to harvest: 30 days

This peppery green is right behind lettuce in terms of harvesting, so it’s a great choice for a quick-growing salad garden. You can begin picking the outer leaves when they’re at least 2 inches long, and continue picking through winter.

Depending on the variety, arugula can withstand temps as cold as 20°F to 25°F, but growth will slow down as the amount of daylight wanes.

Favorite varieties: Rocket, Wild Rocket, Astro, Rocky

Baby bok choy heads arranged on a rustic wooden surface

8. Baby bok choy

Seed to harvest: 30 to 40 days

While regular bok choy takes months to mature, the smaller cultivars (most often referred to as baby bok choy) are ready for harvest in just one month! But can you simply pick regular bok choy in the baby stage? Definitely—you can even eat the seedlings if you need to thin the crop.

The trick to making bok choy last longer in the garden is to treat it as a cut-and-come-again crop, instead of picking the entire head. If you snip just the older outer leaves from each plant, you can keep the plants going for quite a while.

Favorite varieties: Toy Choy, Baby Choi, Pak Choy White Stem, Canton Pak Choi

Close-up of serrated leaves on green mizuna plant

9. Mustard greens

Seed to harvest: 30 days

There are endless varieties of mustard greens to choose from and they range in flavor from mildly spicy to super peppery. Mustards make an excellent fall crop because they grow well when the weather’s warmer in late summer, and continue to thrive in cold weather. (They can even take a light frost.)

You can harvest mustard greens in the microgreen stage, baby leaf stage, and all the way up to full size.

Favorite varieties: Mizuna, Tendergreen Mustard (Komatsuna), Red Giant, Tatsoi

Close-up of frilly green and purple kale leaves

10. Kale

Seed to harvest: 30 days

While it typically takes kale around 60 days to mature, the small, tender leaves can be picked in half that time.

Baby kale also has a less intense flavor than its full-grown self, so if you’re sensitive to the bitter compounds in brassicas, it’s the best time to harvest for salads. You don’t need to “massage” baby kale to soften its texture, and the stems are thin enough to be edible.

Favorite varieties: Nero Toscana, Blue Curled Scotch, Red Russian, Redbor

More posts you might find helpful:

About Author

I'm a plant lover, passionate road-tripper, and cookbook author whose expert advice and bestselling books have been featured in TIME, Outside, HGTV, and Food & Wine. The No-Waste Vegetable Cookbook is my latest book. Garden Betty is where I write about modern homesteading, farm-to-table cooking, and outdoor adventuring — all that encompass a life well-lived outdoors. After all, the secret to a good life is... Read more »

No Comments

    Leave a Reply

    This site uses Akismet to reduce spam. Learn how your comment data is processed.