Brussels Sprouts

A Brussels sprout is one of several types of cabbage, bred and developed over thousands of years, from when wild cabbage was first cultivated in the Mediterranean region. This specific variety became popular in Europe in the 16th Century, in the area around Brussels, Belgium. Like broccoli, cauliflower, kale, and several other “cole crops,” or Cruciform vegetables, Brussels sprouts have a strong flavor, with some bitterness adding some depth to the flavor. Some do strongly dislike them, but they remain an extremely popular vegetable, and are served and savored all over the world!

Brussels sprouts are pretty healthy vegetables too, being high in vitamin C, and vitamin K. They are also a good source of fiber, and beta-carotene. There is a huge variety of options for preparing them. Brussels sprouts can be steamed, boiled, sautéed, roasted, grilled, or even deep-fried! The full flavor of this plant comes with cooking them properly. The glucosinates in all cruciform vegetables add that bitterness, but cooking in olive oil or butter, or steaming properly and preparing with good spices does a lot to bring out the good flavor. Growing up I hated Brussels sprouts, but as an adult, having them after being prepared correctly completely changed my mind!  

• Brussels Sprout (Brassica oleracea var. gemmifera)
• Biennial (annual)
• Full sun
• Soil should be slightly acidic to neutral (6.5 to 7.0 ph)
• Rich soil, with good compost
• Garden seed starting:

          1/2” deep 

          24” apart 

          Thin to about two feet apart (or a little less) when 6” or more tall

• Garden transplant starting:

          Container sized holes

          24” apart (or a bit less)

• Containers:

Single plants in 16″ deep, and 16″ wide pots, spaced 16″ apart in larger pots 

• Rows should be about two feet apart.
• Water regularly, keeping the soil moist
• Climate Zones 2-9 

One thing to be aware of when growing Brussels sprout plants is wind. These plants grow on tall, leafy stalks, and are prone to be blown over in strong winds. Staking individual plants can help immensely with this! One hybrid variety, Jade Cross, is more compact and will stand up to high winds better than some others. Other Jade hybrids are often compact, as well. Some are earlier producers, such as the Churchill and Royal Marvel. The Bubbles variety is more heat resistant than most, and the Diablo, while it takes a bit longer to mature, can handle quite a bit more frost than other Brussels sprouts. 

For those gardeners who like to harvest their own seeds, there are very good types of open-pollinated heirlooms as well. The most common include varieties like the Catskill, as well as the Long Island Improved, which is a good producer. Another one is the Rubine, with purplish good-tasting sprouts, though it does produce more slowly. There are many other types of heirloom and hybrid seeds available as well.

Brussels sprouts take a while to mature for harvest. 90 days, or longer, is fairly typical. This is a cooler weather plant, it does not do well in the warmest weather, especially at harvest time. While spring planting is ok in colder climates, in many places it’s better to plant in late summer to early fall and harvest in the fall. A little bit of frost does not hurt a Brussels sprout when it is full-grown! 

For garden planting, when planting directly in the ground, the seeds should be planted eight to ten weeks before the first fall frost, and thinned to about two feet apart when they reach about six inches in height. If using transplants, (recommended) when planting space them two feet apart.  Good, rich, loamy soil is important for Brussels sprouts. These plants need nutrients! One that’s essential is boron.  If you notice smaller buds and hollow stems, add some boron to the soil. One easy way to do that is with Borax. Yes, really! Dissolve a tablespoon in four-to-six quarts of water, and sprinkle that over every 50 square feet. Only do this if you see the smaller buds or issues with the stems, and don’t overdo it. 

Container gardening is another great option for Brussels sprouts.  For best results, start seedlings in small containers, and transplant the best plants into a large pot with one plant per pot. Water the soil thoroughly, so that all the soil is moist, to start. A container that holds about five gallons or more, and drains well, is the best option. Brussels sprouts need room. They should be transplanted when they are about six inches tall, just like with garden plants. If planting multiple plants in the same container, use even larger ones, and space them about two feet apart. 

It is especially important to ensure that the plants have very rich soil, to keep this nutrient-hungry plant healthy. Fertilization is more important for potted Brussels than it is for many other plants. Do this at least twice: once early in their growth, and again about halfway through the season at minimum. Light sprays of organic mixes every few weeks is even better. Regular watering is important for garden Brussels sprouts and even more so for those in containers, the top of the soil should be kept moist, but not too damp.

Aphids, cabbage loopers, and cabbage worms, are often the biggest problem pests. Cabbage worms and loopers can be removed by hand, and aphids by sprayed with soapy water, or if needed, treated with neem oil. Cutworms and earwigs are a concern for seedlings, but transplanted Brussels sprouts are not bothered by them. Other pests can include armyworms, leaf miners, and slugs and snails.

There are several good companion plants that do really well with Brussels sprouts. Mint, lavender, yarrow, and other aromatic herbs can attract ladybugs, as can fennel, coreopsis, and chives. These are all good to harvest as herbs, and having them nearby can help to control aphids on your plants. Other plants that do well with them include onions, radishes, greens like lettuce and spinach, and tomatoes. If you are intending to harvest seeds from heirloom plants, don’t plant different varieties of Brussels sprouts nearby, to avoid cross-pollination. 

Cole crops like Brussels sprouts, broccoli, cauliflower, and others, share many of the same diseases, such as clubroot, downy mildew, and powdery mildew. With clubroot the leaves wilt, the sprouts stay small, and the roots get huge. If this happens, pull the plant out, and dispose of it safely away from your garden. Don’t compost! If you see brown spots on the leaves and a furry-looking growth, this is downy mildew. Copper fungicide is the best treatment for this, and neem oil can also be effective. Powdery mildew is a hot and dry weather disease, showing first as white spots. This can be treated with baking soda solutions or vinegar sprays. Planting in the fall can help with this, due to the cooler weather. The naturally cool weather Brussels sprouts can usually avoid powdery mildew if planted for harvest in late fall.

It’s a good idea to prune any yellow leaves. You can increase the production of sprouts by pruning the growing tips of the plant, about midway through the season in the late summer. The best time to harvest is in the fall, after the first few touches of frost.  Brussels sprout varieties grow to full maturity in 90 to 110 days, with most kinds close to 90 days.  Harvest when the sprouts are large and bright green. Older yellow sprouts will be bitter. It’s best to harvest gradually, picking the largest first, and waiting for the smaller ones to fully mature. Cold weather improves the flavor, due to increased sugar production, so large green sprouts harvested with a little snow on the ground will be the best ones! 

To harvest the seeds, save one or more of the plants with unharvested sprouts near the end of the season. Wait until it flowers, and cut the stalk. Carefully turn it over into a large plastic or cloth bag (to catch all the seeds), and pull the seed pods off from the flowers, and into the bag. There will be a lot of seeds, and it’s easy to lose them. Seed pods tend to burst when they get dry. If that happens inside a bag, you can save most of them. Allow them to dry, then break the seed pods, and separate the chaff from the pods. Keep them in a dark, dry, cool place, and you will be all set for the next planting!