Brussels sprouts are a close cabbage relative of unusual appearance: the mature plant has an edible crown of fairly large leaves (which can be prepared like cabbage) and a 2-3 foot stem completely covered with golf ball size, cabbage like sprouts. These European natives are fairly easy to grow where summers are not too hot, long, or dry.
Brussels Sprouts prefer a sandy soil rich in organic matter, well draining, and not too heavy. They also need full sun exposure. Before planting, incorporate 2-3 inches of well composted organic matter and 1-2 lbs of all-purpose fertilizer (we recommend “That’s All it Takes” complete fertilizer) per 100 square feet and work them into the soil to a depth of 4-6 inches. Heavy, clay-based soils must be amended with compost and organic matter to encourage and allow good root development. If you have heavy clay soils, we recommend 4-6 inches of organic matter and 50 lbs of Utelite or Zeolite per 200 square feet added to the soil each fall for multiple years to increase drainage and nutrient availability. Over time, you can create a better growing environment for your garden plants to thrive in and produce. Please see our information sheet “Preparing your Soil” for more detailed info on soil preparation before planting a garden.
Like other Cole crops, Brussels sprouts tends to bolt when temperatures are high so plant in cool weather (March & April). Set out plants in Late March or April – Don’t wait until May, as the heat can stunt the early development of your crop (young plants resist a light frost but not a hard freeze). When planting starts, place plants 1.5-2 feet apart in the row, with 3 feet between rows. Planting into plastic or fabric mulches will accelerate early growth and encourage higher yields as well as suppress weed development. For best results, water immediately after transplanting with Kangaroots rooting solution and again for the first 2-3 waterings. This will prevent transplant shock and give your transplants the best possible opportunity to thrive. When planting seed, plant 2 seeds every 12-18” and about ¼ - ¾ inch deep, and thin the sprouts when plants have 3-4 true leaves. Remember, Brussels can withstand cold temperatures and light frosts; they produce best in weather that does not exceed 70 degrees Fahrenheit. Brussels require a fair amount of time to mature, so we have had best results planting them in Early August, and harvesting in cooler October temperatures.
Anderson’s sells the Long Island Improved variety (90 days). They are a uniform plant that can reach 20 inches tall. This variety produces cabbage-like balls that are up to 1.5 inches round from the base of the plant up stem. It is best for late fall and winter harvests as a few light frosts will improve the flavor. A great variety for freezing. WATER Water Brussels sprouts deeply and frequently while trying to maintain even soil moisture. Brussels sprouts needs consistent watering for high quality and quantity production. Water stress during growth and bud production will result in premature flowering, bitter taste, and poor quality. Use a soaker hose for uniform water distribution and water lightly every 4-6 days to maintain soil moisture during these essential growth stages. More water might be necessary as daytime temperatures rise above 80 degrees. A light compost mulch can help as well if daytime temperatures start to climb higher.
Apply ½ cup per 10 feet of row of “That’s All it Takes” complete fertilizer or Happy Frog Organic Tomato & Vegetable Food 4 weeks after transplanting or thinning to encourage vigorous plant growth. Apply an additional ¼ cup of nitrogen-based fertilizer when the sprouts begin to grow taller than 8 inches. Fertilize again after lower leaves are removed. Place the fertilizer 6 inches to the side of the plant and work it lightly into the soil before watering. We also recommend treating your Brussels sprouts seed or plants with beneficial microbes and mycorrhizae (Kangaroots or Myke). These added helpers bring nutrients and water directly to the plants that host them, making them stronger, more resistant to insects and diseases, and more drought tolerant.
Keep the weeds to a minimum with the use of plastic and organic mulches. We prefer the Pro 5 weed barrier as it allows water and nutrient to pass through, but stops even the most difficult weeds as they germinate. Treflan and Corn Gluten weed preventative herbicides are also very effective ways to stop weeds before they start, saving you hours and hours of weeding. Be sure to control weeds when they are small to ensure damage is not done to sprout root systems when weeds are removed. Practice crop rotations to discourage pest problems. Brussels sprouts are subject to aphids, cabbage loopers, imported cabbage worms, and cabbage root maggots. Row covers will help protect plants from all of these pests. All caterpillars may also be controlled using Bacillus thuringiensis (B.T.), spinosad, or pyrethrin. We prefer to spray Spinosad (since it is bacterial, it has no effect on people or pets) early or late in the day for best caterpillar control. Aphids can be controlled with an insecticide like Ferti-lome Broad Spectrum Insecticide or Ferti-lome organic Triple Action.
Begin picking sprouts when big leaves start to yellow. Harvest the sprout from the bottom of the stem to the top, snapping off firm green sprouts that are slightly smaller than a golf ball. Remove any side leaves growing below the harvested sprouts. More sprouts will continue to grow at the top of the stem as the plant matures. Approximate yield will be 3 to 5 pounds per 10 foot row. Mark has an amazing recipe for Bacon Braised Brussels Sprouts with balsamic vinegar and pomegranate that is to die for. So delicious.