How and When to Harvest Brussels Sprouts: 11 Pro Tips

Brussels sprouts have gone from being the dreaded vegetable of your youth to the “it” veggie. These small, round vegetables are actually the blossoms of cultivated Brassica oleracea, the same species as broccoli, cabbage, and more.

What makes this vegetable a bit of a challenge is its long-growing window as well as gardeners’ general unfamiliarity. You may feel confident about when to harvest a cherry tomato, jalapeno, or summer squash, but knowing exactly when and how to slice off a Brussels sprout is a whole different ball game.

Fortunately, it’s not as complicated as you think. Whether you’re growing Brussels sprouts for the first time or the fifth, there’s always room to learn. We’ve gathered 11 pro tips to help you get the most of your harvest from beginning to end.

Select Seeds Strategically

The ultimate Brussels sprouts harvest starts with planting the right seeds. While most gardeners typically plant in spring with the intent to harvest in autumn, warm-regions gardeners can also plant in autumn and harvest them in spring. 

Determine the window of time in which you plan to grow yours, as you will want to choose seeds for a cultivar that grows to maturity within the appropriate time window. While cultivars like ‘Silvia’ take about 100 days to reach maturity, ‘Long Island Improved’ can be right in as little as 85 days.

This is more of a concern for growers in colder zones, where the available growing window for this long-season crop is more limited. Brassicas can survive temperatures around 20°F (-7°C), but don’t expect them to survive for long.

Some cultivars are bred for additional frost resistance, which may be important depending on where you live, and others are even bred for disease resistance. If your brassicas have suffered from black rot in the past, you may want to seek out a cultivar that is resistant to black rot.

‘Silvia’ is a particularly strong variety, with some resistance to black rot and high resistance to Fusarium yellows. It even resists early bolting.

Plant At The Perfect Time

Planting this veggie at the correct time is crucial and will help you determine when you should start harvesting for maximum freshness. Because they have such a long growing season, it’s often advised that gardeners plant in spring or early summer to harvest in fall.

Depending on the variety, expect Brussels sprouts to reach their maturity around 12 to 15 weeks after starting from seed. Consider the “days to maturity” for the variety or cultivar you’ve chosen, and make note on the calendar for when you should anticipate the first harvests. 

If possible, try to plan around bolting, too. These plants grow best in temperatures between 45 and 75°F (7-24°C), and when it gets too hot, they might bolt. This means they may start putting energy into producing flowers instead of sprouts.

Between the lengthy amount of time required for these plants to produce top-tier veggies and their tendency to bolt, determining the right time frame can be a challenge. If you really want to harvest a plentiful volume of sprouts, significant foresight must go into time management.

If you’ve struggled with bolting brassicas in the past, mark your calendar so you can plan around troublesome times. It would be worth your effort to seek out bolt-resistant cultivars, too.

Keep Your Plants Clean

Now that your plants are growing happily, it’s important that you keep them neat and tidy. You may discover yellow or browning leaves on the plants, and you should remove them. You can also get rid of lower leaves on the stem. Leaving dying plant material around can decrease your harvest.

You want the plants to put all their energy into creating the sprouts, so there’s no reason to keep these damaged or unnecessary leaves around. When removing stubborn leaves, be sure to use sharp pruners instead of tugging on the plant, which causes unnecessary stress.

Regularly weed around your plants as well. These weeds will compete for nutrients, space, and water in the soil. They can also harbor pathogens. These brassicas have a long growing season, providing plenty of time for pests to make their way over from nearby weeds.

Another way to maintain tidiness around these vegetables is to use mulch. Spreading some type of mulch along the base of your plants helps the soil retain moisture, assists in weed suppression, and can even keep the roots warmer as you progress into winter. It also looks nice and fresh.

If you’ve had issues with certain pests in the past, you could also use row covers to keep young plants safe from unsightly damage. Even some simple netting on top of brassicas and other small plants can save them from the ugly wounds of nibbling pests. It could also potentially save you from diseases that are spread by pests from taking hold.

Anticipate the Harvest

Now that your sprouts are slowly forming, it’s time to plan for your perfect harvest. Based on when you started seeds or transplanted and your plants’ predicted days to maturity, you should have a rough idea in mind.

Consider this time frame, which is when you should first start looking for any that are ready. If you aren’t the kind of gardener to go outside each day for updates, perhaps make a note on your calendar.

Also, make sure you know when your first frost is supposed to arrive. Like other brassicas, Brussels will live through the first frosts. They might even be tastier at this time. However, once the first frosts have passed, the 20-degree weather that will stop your plants from producing is on the horizon.

This is your overall gathering window, roughly from the predicted maturity date until consistent 20-degree weather. Write down these potential dates somewhere so that you don’t forget and miss a sprout.

Start Harvesting ASAP

It’s important you start harvesting as soon as the little rounds begin to form. The veggies will have the best texture and flavor when they’re still green and tightly bound. Older sprouts will begin to yellow and loosen. You can still eat these, but they won’t taste as good.

Keep an eye on your plants and gather from them as soon as you see peak Brussels. In addition to their color and how tightly wrapped the leaves are, you can evaluate their size. Though there is some variation based on variety and cultivar, Brussels should be about one or 1.5 inches in diameter. They should also be firm.

Once the size is right, don’t wait. Harvest right away. If you see some yellow leaves, you may be able to remove them. As long as the sprouts are still green underneath, they will still taste good and have a reliable texture. But if they’re yellow all the way through, then you’ve missed the peak window. 

If you miss a few, it’s not the end of the world. One plant will continue to produce many. Simply learn from your mistakes and vow not to let any more pass the window of maximum freshness while still attached to the plant.

Harvest the Oldest Sprouts First

These plants will produce sprouts all along the vertical stem, with the oldest at the bottom. The oldest will reach their perfect harvest window first. So when you go outside to check on your plants, look towards the bottom.

If you don’t remove these older buds, they’ll mature quickly, making them less desirable for harvest. To get the most out of your experience, harvest them as soon as possible.

Gather these sprouts first so your plant can put energy into the rest. While it may be tempting to collect them all at once, you will see that the younger ones aren’t yet ready. These veggies are truly an exercise in patience.

Check Regularly

Once you start collecting, continue to do so regularly. A good way to manage your plants is to check on them every couple of days, harvesting anything that is ready. This ensures that you’re always bringing peak-fresh veggies into your kitchen.

You can even check every day if you wish, though there probably won’t be an enormous change from day to day. The good news is that Brussels sprouts are relatively easy to store in the fridge, so you can store them for a little while until you have enough to create a dish.

To store, place them in a plastic bag and put them in the crisper drawer. They should last at least for five days, though you may find that they last much longer. Check for more that are ready to harvest every few days and add them to this bag.

Use Clean, Sharp Tools

It’s important to keep the plants clean by removing dead or dying leaves, but it’s also critical to use clean, sharp tools when harvesting. You can pick sprouts by hand, but removing them with the proper tools is preferable.

Keep your pruners (or any garden tools) clean and sanitary. These brassicas have a really long growing season, which means there’s an enormous window of time for plant pathogens to spread.

The list of potential diseases and pests that may affect Brussels sprouts is somewhat lengthy. Diseases such as black rot, bacterial leafspot, downy mildew, root rot, verticillium wilt, and white mold can all damage these brassicas, in addition to pests such as nematodes, aphids, thrips, and imported cabbageworm larvae.

Each time you slice off a sprout, you’re creating a small wound in the stem that could introduce disease. Dull tools that cause a more ragged wound on the stem cause even more stress. The least you can do on your end is sanitize any tools that come in contact with these plants. The best practice is to clean and disinfect garden tools with each use.

Speed Up the Process

This step is optional but can make a significant difference depending on your growing season, especially if you started your seeds or transplanted late.

Research your predicted first frost date. When it’s about a month or even six weeks away, you may want to chop off the top of your plants. Once you do this, the plant will stop putting as much energy towards growing tall and growing leaves. Instead, it will speed up the process for the remaining sprouts, putting energy into them instead.

This can help the remaining sprouts ripen in time for you to gather them. Remember, these plants can survive frosts and cold temperatures, but they won’t survive long once temperatures consistently hit 20°F (-7°C) or lower. 

With the first frost only four or so weeks away, any new growth from the top will not have enough time to develop and reach optimal quality. You might as well remove the top of the plant and hope more of the existing buds will ripen in time.

Where exactly should you cut? Make a clean cut (with a sharp, disinfected knife) a couple of inches from the top, just above where the sprouts are growing.

Collect Your Final Harvest

Healthy plants will keep growing well into winter, but they will stop producing sprouts once the outside temperature hits 20°F (-7°C). Depending on where you’re located, this could happen as early as fall. 

This milestone is not the same as the first frost. Frost doesn’t bother Brussels sprouts, and in fact, those harvested after the first frost are often some of the best. But once you have indeed reached the first frost, start keeping an eye out for 20 degrees in the forecast.

When 20 degrees approaches, it’s time to collect your final harvest. You can pick the last few on the stem, or you can actually just harvest the entire stem. Use a sturdy set of loppers to remove the whole stem close to the soil line.

You can eat any small remaining buds. They’ll be just as good as the others, only smaller. You can also eat the stem itself. Prepare it the exact same way you would broccoli stems. 

Plan for Next Year

Once you’re finished harvesting for the season, one of the best things you can do to improve as a gardener each year is to take notes about how it went. Next season will be here before you know it, especially if you intend to start seeds indoors.

Planning for next year now, while everything is still fresh in your mind, is the best way to correct any of this year’s mistakes or repeat this year’s successes.

Write down any issues you had concerning pests or diseases so you can research how to prevent or manage them next year. If you grew multiple cultivars or in multiple locations, make sure you note which did the best and why you think that happened. If you discovered your new favorite way to prepare Brussels sprouts in the oven, right that down too.

Don’t forget to experiment with how and when to harvest your veggies, and find which flavors and textures are ideal for your recipes.