How To Grow Brussels Sprouts (Plus 3 Varieties You Can Pick After Frost)

As a kid, you couldn't have convinced me to eat a Brussels sprout. Yuck! I think they were served boiled in the school cafeteria. But, now I find them delicious. The key is proper cooking of fresh Brussels sprouts (it's always Brussels, not brussel). At the end of the article, we’ll have a few culinary tips.  

Brussels sprouts are in the Brassicaceae family, the same as cabbage, broccoli, and kale. And like those veggies, we consider them cool-weather plants. Brussels sprouts are biennials, meaning they take two years to complete their life cycle. If you leave them in your garden over winter, they'll likely continue to grow the next year but won't make more sprouts. Instead, they'll flower and set seed pods. 

Planting Brussels Sprouts

Brussels sprouts have a reputation as being difficult to grow, mostly due to issues with sunshine and fertility. Brussels sprouts need a site in full sun, 6-8 hours daily. Lack of sun is often the issue for gardeners who can't get their Brussels sprouts to make edible-sized sprouts. More sun equals a larger plant and, eventually, fatter sprouts for the kitchen. 

Like most vegetables, they need soil that is well-drained and fertile and a pH above 6.0, although the closer to neutral (pH of 7), the better. Work in some aged manure or finished compost prior to transplanting to increase fertility and improve the soil structure. 

Because Brussels sprouts and other brassicas are heavy feeders and take a lot of nutrients from the soil, rotating them around in your garden is important. The guideline is to not grow them in a spot where other brassicas have been planted in the last three years. That can be tough in a smaller garden, so if you do have to plant them in a spot used for other brassicas, pay special attention to soil amendments and get a soil test.

Starting Brussels Sprouts from Seed

Brussels sprouts are most often started indoors and transplanted outside. They require a long growing season; most varieties will require 90-100 days after transplanting to reach maturity. 

Start Brussels sprouts from seed about 4-6 weeks before you plan to transplant them outdoors. Southern gardeners may have better success with this cool season crop by starting seeds indoors in midsummer and transplanting outdoors once temperatures begin to cool off in early autumn. 

• Fill 72-cell plug trays or flats with moist seed starting mix.
• Plant 2-3 seeds in each cell, about ¼ to ½" deep.
• Cover the seeds and use a humidity dome or plastic wrap to maintain moisture levels until they sprout.
• Once sprouted, remove the humidity dome and keep the soil slightly moist, watering from the bottom of the tray. 
• Provide supplemental lighting to achieve 10-12 hours per day of light. 
• When the seedlings have reached about two inches tall, snip off all but the strongest plant in each cell.

Transplant seedlings after your last frost in spring. Remember to harden off the seedlings before planting out. Space Brussels sprouts seedlings 18-24 inches apart, and if in rows, leave about 30 inches between rows. It's hard to leave so much space in the garden seemingly empty in spring, but a properly fed and happy Brussels sprout plant can get huge. 

Plant the seedlings a bit deeper than they were in their original plugs, about up to the first set of leaves. Firm the ground around them well to help them stay upright as they grow.

Care and Maintenance of Brussels Sprouts

Young Brussels sprouts need to be watered whenever the soil starts to feel dry an inch down. Use your finger and stick it into the soil. If it feels warm and dry past the pad on your index finger, it's time to water. As the plants mature, they can tolerate a bit of time between rains, but you'll still need to water during dry weather.

Keep weeds down and soil moisture up by mulching around and under your Brussels sprouts. These plants are going to be in the garden all summer and autumn, so save yourself some weeding and get the mulch down early.

Brussels sprouts are heavy feeders and need a good supply of nitrogen. Work in some aged manure and finished compost before planting, and you won't need to do much for fertilizing Brussels sprouts. However, in less than ideal conditions, provide fertilizer every few weeks, stopping around midsummer. Continuing to fertilize will delay the sprout formation. You'll end up with huge plants but few sprouts.

Stake tall stems to help them remain upright, or let them grow through netting supported on poles. Bamboo stakes or hazel sticks provide enough support. You can also mound up the soil a few inches around the stems.

Many gardeners snip off the top three to six inches of the stem about a month before their first frost to encourage the sprouts to develop. Plants running a little behind that haven't fully formed their sprouts can be tricked or shocked into putting all remaining energy into their sprouts instead of growing taller and larger. Don't forget those top leaves are great when cooked like collard greens.

As the plant matures, it's common for lower leaves to start yellowing and even fall off. Go ahead and remove those lower leaves, starting about 6-8 weeks before your first frost. They can be snapped off or trimmed about half an inch from the stem with a knife or shears. 

Removing the lower leaves will increase airflow, which is always helpful in reducing fungal issues and helps stimulate the plant to put energy into developing those sprouts instead of supporting the old lower leaves. Take care to avoid damaging the sprouts growing from the joint of the leaf and main stem.

Harvesting Brussels Sprouts

Brussels sprouts start maturing from the bottom of the stalk first–the lowest ones will be the first to be ready. While you can harvest sprouts anytime after they’ve reached full size, they'll be sweeter if exposed to a few light frosts–a few nights in the high 20s is perfect.

In autumn, harvest a few sprouts from each plant, grasping them and tugging or snapping them downward. Grab the lower ones from each plant and leave the rest for next time, extending your harvest time window to several weeks or longer.

Brussels sprouts are ready to pick when about the size of a walnut or a bit smaller than a golf ball. An inch in diameter is perfect for most varieties, although a few grow much larger sprouts. 

Pick Them After the Frost

Like other brassicas, Brussels sprouts' flavor improves after some light frosts. The sugars develop and improve the flavor. All varieties we carry are perfect for harvesting after the frosts begin, and in fact, we recommend it. 

• 'Long Island Improved' is an old favorite that gardeners have been returning to for a century. It's a shorter, more dwarf plant better for smaller spaces and matures in about 90 days after transplanting. 
• 'Catskill' Brussels sprouts are another heirloom variety, with strong stalks and extra large green sprouts that can reach two inches in diameter.
• 'Jade Cross' is a hybrid, producing vigorous plants and heavy yields. The oval-shaped sprouts are flavorful and plentiful. It's a favorite of Southern gardeners and can be planted later in summer for a late fall crop.

Culinary Tips for Brussels Sprouts

Perhaps the simplest (and my favorite way) to prepare Brussels sprouts is to roast them. 

• Preheat the oven to 425℉.
• Chop larger sprouts in half and leave small ones whole. 
• In a large bowl, toss the sprouts with olive oil, salt, and pepper. That's all they need.
• Spread them out on a parchment paper-lined baking sheet, being careful not to overcrowd them. They shouldn't be touching. 
• Roast for about 20 minutes. They should be tender inside and golden brown (hopefully with crispy bits) on the edges.

Grilling Brussels sprouts is also a good way to caramelize their natural sugars and bring out the flavor. Toss them in oil and seasoning, then skewer and grill over moderate heat for about 5-6 minutes, turning halfway. 

However you prepare them, a bit of oil and some heat is the key. Sauteeing them with butter and shallots is also good, and of course, a little bacon goes a long way to convince non-sprout-eaters to give them a try. Avoid low and slow methods that turn these tasty little spheres into strongly flavored mush.