Brussels sprouts are a unique garden addition due to their relative novelty as a home-grown vegetable and the tall stalk on which the sprouts actually grow. Studded with leaves, the mature Brussels sprout plant stands after most of the produce has faded away, and continues to produce food into the winter.
Brussels sprouts are picked over several times instead of just once. Each picking stimulates new growth along the stalk, which can then be re-harvested. During warmer weather, harvests occur every one to two weeks, and yield between two and six sprouts. This is delayed to three or four weeks once cold weather sets in, but harvest yields 10 to 15 sprouts. Although there is no set number of sprouts for each stalk, a single plant can produce up to 3 pounds of sprouts.
Brussels sprouts are a cool-weather crop, grown during the summer for harvest in fall and early winter. This means they are planted at the tail end of spring, usually in early June. You may either set seeds 12 to 18 inches apart in rows 24 to 30 inches apart for home growing, or you can transplant starts after growing them indoors for four to six weeks. Seeds and transplants can both go in the ground in early summer, so for an earlier harvest start plants inside.
Brussels sprouts require a lot of nitrogen, as well as the other main nutrients, potassium and phosphorous. To encourage good production, ensure a soil content that is high in nitrogen. Apply a store-bought fertilizer such as 10-20-10 or 13-13-13 halfway through the growth season, or use aged chicken manure. This excellent source of natural nitrogen should be worked into the soil around the plant base three weeks after planting, at a rate of 1 quart per plant.
Because late spring-planted Brussels sprouts take around 85 to 95 days to reach maturity, they are generally first ready in early fall. Sprouts mature lower on the stem first, so start to harvest there when they are 1 to 2 inches in diameter and firm to the touch. If leaves turn yellow, it is definitely time to pick, otherwise the sprouts will lose their flavor.