Frequently Asked Questions
Why are my brussels sprouts loose and leafy instead of tight?
Loose sprouts usually come from warm weather during sprout formation, loose soil, or too much nitrogen. Sprouts form best when nights turn cool in fall, and plants grow tighter buds in firm soil, so press down the soil around the base of each transplant. Avoid heavy nitrogen feeding late in the season, which leads to leafy growth. Crowded plants also form looser sprouts.
Should I top brussels sprout plants and remove the lower leaves?
Both can help. About three to four weeks before you expect to finish harvesting, cut off the growing tip at the top of the stalk. This redirects the plant's energy into swelling the sprouts instead of growing taller. Remove yellowing lower leaves as they appear, which improves airflow and makes sprouts easier to reach, but leave the leaves near the top, which feed the plant.
When should I harvest, and does frost matter?
Start picking from the bottom of the stalk when the lowest sprouts are firm and about one to two inches across, then work your way up as the rest mature. Twist or snap each sprout off. A light frost is a bonus, because cold converts starches to sugar and makes sprouts sweeter, so there's no need to rush in at the first cold night. Plants will keep producing until hard freezes arrive.
Do brussels sprout plants need staking?
Often, yes. Plants have shallow roots and grow tall and top-heavy, so they can lean or topple in wind or wet soil. Hill soil around the base of the stalk when plants are young, and tie taller plants to a stake or bamboo pole. Compact varieties usually hold themselves up better than tall ones.
What pests should I watch for on brussels sprouts?
Cabbage worms, aphids, and flea beetles are the most common. Cover young plants with lightweight row cover right after transplanting to keep moths and beetles from reaching the leaves. Check the undersides of leaves regularly, and handpick caterpillars. Aphids often collect in the crowns and sprout clusters, and a strong spray of water knocks them off.