QUESTION: What is the best way to grow Brussels sprouts? I’m not even sure the best time to plant them. – Tom W.
ANSWER: As Brussels sprouts are a cool weather crop, they prefer temperatures around 60 to 65 degrees F. Fall is the best time to plant Brussels sprouts for optimal growth. Brussels sprouts typically require a minimum of six hours of sunlight exposure each day in most climates. However, in especially warm locations, a bit of afternoon shade should be provided for Brussels sprout plants during the summer.
To get your Brussels sprout plants to grow to their full-size, provide about two feet of space between each plant. Brussels sprouts have sensitive root systems, so pull weeds up by hand to avoid damaging them when weeding and lay out a layer of mulch to help keep the soil moist and cool during warm weather periods.
As your plants begin to develop sprouts, the plants can quickly become top heavy, so provide some form of staking or mound up dirt around your Brussels sprouts so that they don’t end up toppling over.
Brussels sprouts are heavy feeders, so in addition to mixing in well-rotted manure to your potting mix at the time of planting, you will also want to side dress the plants either with compost or manure or with balanced fertilizer 3-4 weeks later after transplanting. Feed again when they’re halfway grown, applying a fertilizer like 10-10-10 or 5-10-5 or 5-10-10 according to the instructions on the product. You can also feed this vegetable crop with liquid fertilizer instead of time-based every other week.
Excess nitrogen will make your plants focus on producing lots of leaves and ignore sprout production, so opt for a low-nitrogen fertilizer when feeding your Brussels sprouts. If any of the lower leaves begin to show signs of yellowing, remove them from the plant immediately so that it can focus its energy elsewhere instead of trying to revive spent outer leaves. Though pruning is not really necessary for Brussels sprout plants, pinching off the plant tops will force your sprouts to mature at a faster rate. For improved flavor, wait until after the first or second frost in your area to harvest the first sprouts in your home garden, removing just the sprouts which are big enough, working your way from the bottom of the plant up.