Prepare the planting area well in advance allowing organic matter to break down and begin releasing its nutrients. Spread 2 inches of compost and 3 or 4 inches of well-rotted manure. Dig both into the soil and thoroughly mix them into the top 6 inches of topsoil.
Work the soil again and dig in high-phosphorous fertilizer, such as 5-10-10, broadcast at the rate of 5 lbs. per 100 square feet one week before planting. For good flavor and yield, Brussels sprouts need uninterrupted growth and a steady nutrient supply.
Dig planting holes for transplants as deep as the plants sit in their containers. Space the holes 24 inches apart in rows 30 to 36 inches apart. In raised beds, the plants need 24 inches in all directions.
Transplant each plant. Firm the soil around each plant and water the entire bed well. The plants should be about six weeks old when transplanted.
Mulching the soil with lightweight pine straw conserves soil moisture, keeps the soil cool and deters weeds. Keep the mulch away from the plants' base.
Fertilize the plants several times with a side dressing of high-nitrogen fertilizer starting three weeks after transplanting. Apply a high-nitrogen fertilizer again two weeks later and once again two weeks after that.
Top the plants, or remove the apex or apical bud, when plants reach their full height and lateral buds start developing. This encourages earlier lateral bud development.
Start harvesting as sprouts, the lowest, reach maturity three to four months after transplanting, depending on the variety. Break off the leaf directly below the sprout. Snap the sprout from the stalk. Continue harvesting as long as plants produce.