How surprised were you as an adult the first time you tried a Brussels Sprout again and realized you actually liked them? Sweet and mild, they are vitamin-packed and so versatile they can be eaten raw in a slaw, steamed, roasted, and even fried. Growing your own is so satisfying, and the plants are really cool looking too! 

Besides the delicious flavor and truly infinite cooking techniques, this plant is highly cold-tolerant for all you winter gardeners out there. This crop produces a high yield of sprouts per plant, meaning that while they’re large, the space you use in the garden really pays off. Learning how to grow brussels sprouts can be a little tricky but following these tips and steps should deliver you to a harvest of brussels sprout stalks next season. 

Ready to get growing? Here’s what to expect when growing brussels sprouts: 

This long season crop takes about 90 to 110 days to mature from transplant. This means that it’s 110 days not including the weeks it takes to start the seeds indoors before transplanting. We recommend starting your seeds no less than four weeks before your last frost date in the spring, but the earlier the better - up to 12 weeks early - particularly for fall crops. Whether you grow in the spring or fall will most likely depend on your location. Southern growers tend to have more luck with a fall crop while Northern growers can often grow both a spring and fall crop. This is due to the rate at which it heats up in the summer time in the south, which can quickly become too warm for maturing brussels sprouts. From here it’s a game of protecting this long-season crop from pests (or extremely hard frosts where necessary) long enough for you to enjoy a harvest. Let’s get started. 

Growing Brussels Sprouts  

Growing brussels sprouts can be tricky but mastering this crop is mostly a game of understanding your growing zone.

Brussels Sprouts in Different Growing Zones

In cooler growing zones, like zones four, five, and sometimes six, brussels sprouts can be grown twice a year; in the spring and again in the fall. Cooler growing zones typically have longer, cooler springs than we do in the south which makes for an easier time getting this long-season crop to maturity. 

In warmer climates, like zones seven, eight, and nine, growers will typically want to shoot for only a fall crop. Cooling temperatures at the end of the growing season will help to avoid bolting brassicas experiencing heat stress. Brussels sprouts are very cold hardy so do really well in cool, and even mild winters. There is also far less pest pressure in the fall which helps make this long-season crop a success! 

When to Plant Brussels Sprouts

As we’ve established, the secret to Brussels sprout growing success is knowing your growing zone. Once you have that figured out you’ll know when to get started.

Growing a Spring Crop

For a spring crop of brussels sprouts, you’ll want to provide a long, cool growing season. This is most easily done in cooler, typically Northern climates. You’ll want to start your seeds indoors no less than four weeks before your last frost date. The earlier you get them started (and the bigger they are when they go in the ground) the better. Start your seeds up to 12 weeks ahead of your last frost date. They can be transplanted out before or around your last frost date by about two weeks. For hard frosts that may still occur, tender young plants may require some frost protection, however this crop is cold hardy. 

Growing a Fall Crop 

For a fall crop of brussels sprouts, start your seeds 12 weeks ahead of your first frost date. The timing on this is less flexible as the shorter sunlight hours in the fall can result in stunted or poor growth. Making sure your crop is well established before you have regular hard frosts is a good idea. Fall crops can sometimes be easier because you’re not as worried about hot temperatures - they’re consistently cooling in most places, pest pressure goes down, and weed pressure goes down too. 

Where to Plant Brussels Sprouts

Brussels sprouts will require an area with full sun and well-draining soil that is very high in nutrients, particularly nitrogen. Because this is such a long-season crop, you’ll want to select a location where you can expect it to spend three to four months in the same spot! 

Sunlight Requirements for Brussels Sprouts

This crop needs a minimum of six hours of sunlight per day and more is better. This, of course, gets more challenging as the days get shorter in the fall. That is why we recommend selecting a spot with full sun as that has the best chance of providing the maximum amount of sunlight possible year round. The exception here is when growing a spring crop, some afternoon shade may be beneficial to keep the plant from experiencing too much stress, however, it will still need that minimum of six hours of sun.

Soil Requirements for Brussels Sprouts

Brussels sprouts will need well-draining soil and a high amount of nutrients. The ideal soil pH is around 6.8. Soil pH can be tested with a soil test through your local Extension Agency or with an at-home soil test kit. Soil tests through the extension agency can give you a lot of information including nutrient deficiencies, which can help inform your bed prep. When in doubt, however, simply mix in several inches of mature compost alongside other nitrogen-rich amendments like blood meal, or even just a balanced organic fertilizer. 

Growing Brussels Sprouts from Seed

Growing Brussels sprouts from seed requires that you start them indoors ahead of planting. It’s possible to direct seed them in some places but it’s not recommended as it can add quite a bit of difficulty to an already difficult crop. 

Sow seeds in trays packed with a high quality seed starting mix. Plant one to two seeds per cell ¼ inch deep and just barely cover the seeds with soil, lightly pressing down to ensure adequate seed to soil contact. Keep your trays well-watered until germination, one to two times per day. Once your seedlings germinate, they don’t require as much water, but they should be kept moist - watering, or at least checking the moisture levels, once a day. Like all seedlings being started indoors, you will need to provide grow lights to ensure stocky, healthy plants. 

Transplanting Brussels Sprouts

Once your Brussels sprout seedlings are six inches tall, they are ready to be transplanted. You’ll want to take the time to harden off your seedlings before you put them in the ground. This will increase the likelihood of survival and decrease plant stress! 

The process of hardening off is the process of introducing seedlings to the outside world. Let your seedlings acclimate to the outdoors by putting them out in the sun for an hour, then two, then four, increasing the time as the days go on until they’re spending full days outdoors. Once they’ve been well-acclimated, they’re ready to go in the ground! Transplant seedlings 18 to 24 inches apart in rows 24 to 36 inches apart. Planting your seedlings too close together will result in plants that are competing for sunlight and nutrients, and are more likely to spread disease to each other. Even though this crop requires a lot of space, it’s worth it to dedicate the space to it rather than try to squeeze in extra plants. 

Using a row cover, the weight can depend on the time of year and need for frost protection, can help to keep pests at bay - which are plentiful at planting time for a fall harvest, but can also be helpful to protect spring seedlings as pests emerge later in the season.  

Caring for Brussels Sprouts

Once your seedlings are transplanted and established, the hardest part is over. Now, your main job is to keep pests at bay, ensure your crop has enough nutrients and water, and wait to harvest! 

Watering Brussels Sprouts

Brussels sprouts need at least one inch of water per week but they’ll appreciate an inch and a half if you’re able to provide it. Daily watering will help transplants get established, but once they’re established, water deeply two to three times per week if the rain doesn’t provide enough moisture. Like other brassicas, brussels sprouts are susceptible to fungal diseases particularly on their foliage. This won’t necessarily kill the plant but will weaken it and can ultimately affect your harvest. Take time to water your plants at the soil level so that the leaves don’t get or stay particularly moist, as this can contribute to the spread of disease. Further, applying mulch around the plants can help hold in moisture and suppress weeds.  

Fertilizing Brussels Sprouts

This heavy feeder will thrive if fertilized every three to four weeks. If you know your soil is lacking nutrients, we recommend using a high nitrogen fertilizer. However, if you took the time to amend the soil ahead of planting, you can use a fertilizer that is more balanced like a standard Vegetable Garden Mix or the popular liquid Fish Fertilizer. Applying a high nitrogen fertilizer on top of this once or twice throughout the growing season may act as an insurance policy to getting a great harvest. 

Pruning Brussels Sprouts

As your crop matures, you’ll start to notice that lower leaves will turn yellow and eventually fall off. As the plant grows, we recommend pruning the lower leaves, which will encourage the plant to put more energy into producing buds over leaves. You can wait until the leaves start to turn, or harvest them as the plant grows, allowing at least one third of the leaves on the top of the plant to remain intact. 

Brussels Sprouts Pests and Disease 

Managing the spread of pests and diseases throughout your Brussels sprout patch is your main job for most of the growing season with this crop. Pest and disease control in an organic or regenerative garden often requires integrated methodologies to see the most success. This means that your system should combine an array of biological, cultural, and mechanical methods. This is referred to as Integrative Pest Management. This is a great and adaptable system that can be used to address the many pests and diseases that may plague your Brussels sprout patch. 

Cabbage Loopers

If you see white moths fluttering around your maturing Brussels sprouts, you’ve got cabbage loopers on the way. Look for the round, yellow eggs laid on the undersides of leaves. When found, crush them before they start chewing the foliage. If they’ve already hatched, you’ll see their dark green droppings towards the crown of the plant and notice defoliation. If left as-is, they can defoliate entire plants. Prevention is the best technique. Eggs typically get laid from May to June. Consider covering your brassicas with row cover so they can’t lay their eggs on your crops. You can squish the larval loopers as well, but be sure not to miss any! They’re good at camouflaging. You can also use Bt on these soft-bodied insects, however it won’t stop the moths from laying their eggs. 

Slugs

Slugs are the bane of many growers’ existence. They often hide in mulch and come out at night to feed, meaning you’ll find a number of oddly shaped holes all over your crops with no clear indicator of “whodunnit”! However, if this has been your experience, you’re most likely working with slugs.

Every gardener has their own special trick for tackling their slug problem. These range from beer traps to lining copper wire around the bottoms of plants, which is said to repel them. Many of these don’t work 100% of the time, but they are definitely a great starting point! For extreme cases, iron phosphate is an organically certified — though perhaps controversial — slug repellent that works well. 

Aphids

Aphids are one of the most common pests you’ll come across. While they can be extremely sneaky, keeping a close eye on your crops will help mitigate their damage! If you see any small white, black, or sometimes even green bugs all stuck together covering the stem of your plants, these are likely aphids. They are sucking bugs so they love especially juicy foliage and, left to their own devices, can stunt the growth of your crops and cause eventual death. They spread quickly, so as soon as you start seeing a few, take some action! 

In many cases, a strong stream of water can knock aphids off the plant, and they’ll have trouble getting back up. In more extreme cases, a regular application of neem oil can help to keep populations at bay. If you know aphids are a regular problem in your garden, you may consider interplanting, or companion planting, with beneficial plants that can either deter aphids or act as a decoy to attract them, saving your actual crop from being sucked to death. 

Downy Mildew

This is a very common fungal disease that you’ll often find on many brassicas and other crops. When it attacks younger plants, they tend to not fair as well as mature plants that can live with some fungal issues. Symptoms may first appear as small brown or yellow spots on the foliage - typically starting lower and spreading upwards. This fungus tends to be around, so the steps you should take to avoid this killing off your crops need to be proactive rather than reactive. Be sure to plant your crops at an appropriate distance from each other so the foliage gets enough airflow. Overly wet conditions are a breeding ground for fungal diseases. That being said, you should water your crop at the soil level to not let the foliage get or stay wet for no reason. Further, if or as you see any fungal issues showing up on lower leaves, prune them as much as you're able to limit the spread. 

Clubroot

Clubroot is about what it sounds like. Classified with other fungal diseases, this issue causes a swollen, misshapen root structure and will eventually cause stunted and stressed plants. Because the first signs happen underground, it can be hard to know when this is the issue you’re facing! If you’ve historically had this problem, you’ll want to add lime to your soil well in advance, to raise the pH above seven. This will slow the progression. In an attempt to avoid this issue altogether, practice crop rotation, planting only disease free plants, and watering at the base of plants will help limit the spread. 

Black Spot

Also known as Alternaria leaf spot, this fungal disease shows up first as black spots on your foliage that eventually expand, causing the foliage to become necrotic. The symptoms start low but can spread to the sprouts and heads as time progresses. If your plants are living with it, it doesn’t cause the sprouts to be inedible, but mostly look unappetizing. But typically, the outer leaves of the sprouts can be peeled back. All the same cultural methods you’d use for other fungal diseases apply here in terms of treatment or proactive treatment. 

Season Extension with Brussels Sprouts

Brussels sprouts start out being extremely cold hardy on their own. They don’t bat an eye at 32 degrees, and can even withstand temperatures down to the teens when established. Not to mention, Brussels sprouts get even sweeter with frost! Because you can extend the harvest for so long with this crop, you may even consider keeping it in your winter garden. In many growing zones they can be easily overwintered. In the coldest zones, however, you may have to take some season extension measures. 

Because Brussels sprouts are so frost tolerant, in most climates you will likely only have to use floating row cover on the very coldest of nights. When paired with hoops, this fabric creates a low tunnel that can offer two to four degrees of warmth. This can make or break your harvest when temperatures hit single digits. Take care to remove the frost cloth during the day in order to not inhibit light accessibility, especially when the days are so short. 

Companion Planting with Brussels Sprouts

Companion planting is the practice of planting different crops near each other that help each other grow. Depending on the pairing, the league can tackle pests, nutrient requirements, pollination needs, or maximizing space! Especially helpful for those of us with limited growing space. Here are some friends and foes of Brussels sprouts. 

Friends

Alliums

Alliums like onions and garlic have a strong smell that can mask sweet sprouts and deter pests including aphids and certain beetles. 

Carrots

The deep tap root of carrots help to aerate the soil, loosening and improving soil quality over time. 

Culinary Herbs

Certain culinary herbs such as thyme and sage can be beneficial to plant near your Brussels sprouts. Thyme spreads out and can support weed maintenance in between rows. The strong smell also deters cabbage loopers. Sage’s strong smell will also deter various pests from your crop. 

Foes

Strawberries

Strawberries are heavy feeding crops that will compete with Brussels sprouts for nutrients and ultimately weaken each other. 

Other Brassicas

It is generally not recommended to plant Brassicas close together as they can easily spread and share pests and diseases. Some folks debate that you can easily maintain pest and disease maintenance if they’re planted close together. 

Melons

The sprawling vines of melons will quickly encroach on the space of your Brussels sprouts, ultimately with them competing for nutrients and moisture. 

Harvesting Brussels Sprouts

You’ll find that a sprout is produced at each leaf node. As you’re pruning the bottom leaves, your sprouts will grow at that spot. As it becomes time to harvest, watch for your sprouts and harvest them before they start to turn yellow and eventually open. Sprouts that are ready to harvest are firm, green, and about one to 1.5 inches in diameter. The sprouts do not mature all at once. They can either be harvested in sections, starting at the lowest, most mature sprouts, or wait until a critical mass of the sprouts are mature and harvest the entire stalk. Harvesting sprouts as they grow will result in more harvests and a longer harvest window. Use sharp shears to harvest the sprout at the growing point or to harvest the entire stalk. 

Storage Methods for Brussels Sprouts

There are a few ways to store brussels sprouts once you take them out of the garden. If looking to keep them for several weeks, pull the entire plant out of the garden with the root system intact. From here, put them root-side down in a five gallon bucket. They will keep like this for some time in a protected, but cold area, like a shed or garage. As you eat them, simply cut off the stock at the root and pull off the sprouts to cook. Before storage, take care to remove any yellow leaves or leaves with black spots, as well as any sprouts that aren’t in perfect condition. You may run into some trouble if your storage area is too dry, so keep that in mind when choosing a location. 

Brussels sprouts can also be processed and frozen for later use. Remove your sprouts from the stalk and clean them to remove any dirt or pests. If any outer leaves of the sprouts need to be removed, do that now. Blanche your sprouts for just three to four minutes. Overdoing it will result in mushy frozen vegetables. When you remove the sprouts from the boiling water, place them immediately into a bowl of ice water to stop the cooking process. Take ample time to ensure your sprouts are well dried, either using a salad spinner or paper towels. Lay out your sprouts on a sheet pan in a single layer and freeze them overnight. This will ensure you don’t end up with one frozen mass of sprouts. The following day, put your sprouts into freezer bags. Like this, they’ll store for several months! 

Common Issues with Brussels Sprouts

Leggy Seedlings

Leggy seedlings can be one of the first issues you come across with your Brussels sprouts. If you notice your seedlings have particularly long stems with small leaves and appear to be growing slowly or are otherwise stunted - these are leggy seedlings. You will likely find the seedlings all leaning in one direction toward a source of light. Legginess is ultimately caused by a lack of sunlight early in development. You’ll need to provide more light to your seedlings and/or extend the hours that light is available to them. The earlier you catch this problem, the more likely it is that your seedlings can recover.

Brussels Sprouts Bolting

Brussels sprouts will start to bolt in a number of situations. Typically, bolting is caused by plant stress. Brussels sprouts will bolt if planted at the wrong time of year, particularly if they undergo too-hot temperatures. Water stress can also cause sprouts to bolt. The best way to prevent bolting is to ensure your crop gets the care and temperatures it needs. Once bolting starts, it’s rather difficult to stop the process, so your best bet is to plant at the right time of year, ensure your crop is planted in high quality soil, and keep your plants mulched to keep the soil evenly moist.

All Brussels, No Sprouts

Are your plants growing big and tall but not producing any sprouts? This is a tricky crop. The first thing to think here is that perhaps the plant just isn’t producing sprouts yet. Watch closely just above the leaves at the stalk to see if even small sprouts are forming. It can take 100 days for the sprouts to begin forming, so patience is key. If it’s been plenty of time, it may also be a result of insufficient or uneven water, not enough nutrients in the soil, or plants that are spaced too close together and ultimately competing with each other. 

Ready to get growing? The perfect open-pollinated Brussels sprout is just waiting to thrive in your garden! 

	Article Written by: Hannah Gibbons
	About the Author: Hannah Gibbons, an employee and owner at Sow True Seed since 2020, has a decade of experience in the agricultural industry. Their passion for environmental education and regenerative agriculture has been the cornerstone of their work, aimed at making gardening accessible to all.