Have you been put off by the strong bitter taste of store-bought Brussels sprouts? Do you think they’d be the last thing you’d want to grow in your garden? Well, think again. Homegrown Brussels sprouts have a nutty sweetness to them that is unlike anything you’ll find in a grocery store. Brussels sprouts belong to the Brassica family of vegetables which includes cabbage, broccoli, cauliflower, collards, kale, and kohlrabi.
For the best results, Brussels sprouts need rich, moist, cool soil for growth. The pH should be on the high side, about 6.8. You’ll want to incorporate plenty of nitrogen-rich supplements to the dirt, such as manure or bloodmeal. Brussels sprouts also require more of the nutrient boron than most other vegetables. Without plenty of boron, Brussels sprouts develop small buds and hollow stems. If your plants develop symptoms of this nutrient deficiency, you can dissolve one level tablespoon of borax (such as 20 Mule Team Borax from the grocery store) into 5 quarts of water. Spray it evenly over about 50 square feet of bed. Don’t over do it, however. Too much is as bad as not enough. Don’t add the supplement unless you see the symptoms of deficiency.
When to Plant
Sow your seeds indoors and move seedlings to a shady site outdoors until they’re about six weeks old. If temperatures ever rise above 80 degrees, bring them back inside. You’ll plant your seedlings early to midsummer in the North and middle states, and after the peak summer temperatures have passed in the South. Brussels sprouts mature best in cool (and even frosty) weather, and actually become sweeter after a frost. A mulch of loose straw around the plants will help protect against the heat.
How to Plant
Your Brussels sprouts will get large, so they need plenty of room. Spacing should be about 18 inches apart on short varieties and around 24 inches apart on tall varieties. Space your rows about 30 inches apart. You’ll want to plant the seedlings deeply. You only want half to a third of the plant left sticking out of the dirt. Don’t be afraid to cover it up! Water your seedlings in with a solution of fish emulsion such as Protogrow®, and make sure your plants get about 1 1/2 inches of water a week. Again, keep the ground cool and moist.
Once your plants are about 12 inches tall, you can side-dress with compost or some type of organic fertilizer.
Once temperatures drop below 60 degrees at night, sprouts will begin to form. They’ll start at the base and work their way upward. Begin harvesting when the sprouts are about 1 to 1 1/2 inches in diameter. Remove the leaves around the base as you harvest, but don’t remove the top leaves at all.
You can force the sprouts to mature all at the same time by cutting off the top 6 inches of the plant five to six weeks before your first average frost date. The sprouts will mature about six to eight weeks after the top is removed. If you don’t force the maturity of your sprouts, just harvest as you need them. As long as the temperatures don’t dip below 20 degrees, sprout quality actually improves with freezes.
You can store them in the refrigerator for a day or two, but don’t wash them until you’re ready to cook them. You can also eat the small tender leaves much as you would kale or collards. The larger leaves are not as tender and don’t taste as good.
If your sprouts are loose or in short clusters, the temperatures were too warm when the sprouts were forming. Also, the soil might not have been firmed enough at planting time.
Aphids can also be a problem. You can wash away aphid clusters by spraying with a hard stream of water.