Brussels sprout plants that are healthy can produce a lot of sprouts--just a few plants can keep a family supplied with this vegetable all season. Once mature sprouts are picked, the plant continues to produce. According to North Carolina University College of Agriculture & Life Sciences, after the first harvest, you can expect to harvest more sprouts every week to two weeks, during warm weather.
Like tomatoes, not all sprouts ripen at the same time.
Check the bottom of the plants, where the sprouts usually ripen first. If sprouts are firm and at least 1 inch in diameter, they are ready to harvest.
Hold the plant steady with one hand. With the other hand, break off the leaves directly below the sprout. Use a sharp knife or small pair of shears to cut the sprout from the stem. Do not try to snap or twist the sprout off, as this can injure the plant.
Check sprouts on the rest of the plant to see if they are ready every three to seven days. If Brussels sprouts remain too long on the plant, they can become tough or spongy and lose flavor quality.
Place harvested sprouts gently into a bucket. Avoid throwing or tossing them into the bucket, as they bruise easily (and won't keep as long if bruised). Don't be disheartened if there don't seem to be many sprouts in your first harvest; if the plant is healthy, it should produce more sprouts after the first harvest.
Store the harvested sprouts in a refrigerator until you are ready to prepare them for cooking. Unlike tomatoes and other vegetables, which can be left out for a while to finish ripening, Brussels sprouts can go bad at room temperature.