How to Grow Brussels Sprouts

By: Angela Judd | August 8, 2019

Learn how to grow Brussels sprouts in your garden with this comprehensive guide. It includes information on planting schedules, care methods, and harvesting techniques for these healthy vegetables.

Brussels sprouts (Brassica oleracea gemmifera) prefer a long (around 100 days) cool growing season, which means growing them in hot climates like Arizona can be a challenge. Be that as it may, if you learn how to grow Brussels sprouts in Arizona (and the weather cooperates), the flavor of fresh-picked Brussels sprouts can’t compare to anything you buy at the store.

As the name suggests, Brussels sprouts were first cultivated in Belgium in the 16th century and are an excellent source of vitamins and protein. This cold-loving member of the cabbage family produces miniature cabbage-like heads on a tall main stem surrounded by large leaves.

Fun Fact: the correct usage is Brussels sprouts, not Brussel sprouts, even if you’re only referring to one sprout.

Want to learn how to grow Brussels sprouts? Here are five tips:

1. Plant Brussels sprouts at the right time

The best time to plant Brussels sprouts varies depending on your climate and whether you’re starting from seed or transplanting seedlings.

Generally, Brussels sprouts are a cool-weather crop and do well when they can mature in cooler temperatures. Therefore, they should be planted in early spring for a summer harvest or mid-to-late summer for a fall harvest. They require a fairly long growing season, typically around 100 days to harvest.

If you’re starting from seeds indoors, you can start them about 8 weeks before planting them outside. For a fall harvest, you would typically plant the seeds or transplant the seedlings outside about 10 weeks before the first expected fall frost date.

Remember, these are general guidelines and can vary based on specific local conditions, so it’s always a good idea to check a local planting calendar.

Seeds sprout in 3 – 10 days at 70°F – 80°F (21°C – 27°C). Seedlings grow best at temperatures between 60°F and 70°F (15°C – 21°C).

In the low desert of Arizona, plant Brussels sprouts during warmer weather, and they mature during cooler temperatures.

Start seeds indoors: July – September
Plant transplants outside: September 15 (or when nighttime temps begin to cool down) – November

2. Plant Brussels sprouts in the correct location

Brussels sprouts grow best in compost-rich, fertile, well-draining soil. Add additional compost to the planting area, and work it into the soil before you plant. If planting seedlings, do not let transplants dry out or get stunted in packs.

Although Brussels sprouts prefer cooler weather, they grow best in locations with plenty of sunlight.

In the following seasons, rotate the location for Brussels sprouts in your garden to prevent soil-borne diseases and the depletion of soil nutrients.

3. Give Brussels sprouts room to grow

If planting seeds outside (not generally recommended), sow Brussels sprouts seeds ¼ to ½ inch deep (0.6 to 1.3 cm) and about 4 inches (10-12 cm) apart. Once seedlings have two sets of leaves, thin to 1-2 feet (30-60 cm) apart.

Plant transplants (recommended way to plant) 1-2 feet (30-60 cm) apart.

For square-foot gardening, space plants 1 per 1-2 squares.

4. Care for Brussels sprouts correctly

These plants have a dense, shallow root system. The roots are close to the surface and are easily damaged.

Water newly-planted sprouts thoroughly. If planting seedlings, do not let transplants dry out or get stunted in packs.
Add 2-3 inches (5-7.6 cm) of mulch around plants to keep the soil moist and prevent weeds.
Water Brussels sprouts at the base of plants, not on the leaves.
Pull weeds when small to avoid disturbing roots.
At maturity, the plants are around 2 ½ feet tall (approximately 76 cm). If your area is windy, stake Brussels sprouts at planting so as not to disturb roots by staking later.
Feed Brussels sprouts before planting with compost and once or twice during the growing season with fish emulsion. I use this one from Amazon.
Watch out for pests such as cutworms (use cutworm collars around young plants), aphids (spray off with a blast of water), and cabbage loopers (handpick or use Bt – I use this kind from Amazon).

5. Harvest Brussels sprouts at the right time

When growing Brussels sprouts in hot climates, harvesting finishes by early spring. Remember that cool temperatures sweeten the flavor of Brussels sprouts, but warm temperatures cause sprouts to be bitter and loose-leaved.

Cut back on watering as Brussels sprouts near maturity.
Keep an eye out for yellow leaves; this means nearby sprouts are maturing.
Harvest Brussels sprouts when heads are small and firm, about 1 to 1 ½ inches (2.54 to 3.81 cm) in diameter.
To harvest, grasp the sprout with two fingers and twist it off the plant.
Remove yellow leaves above developing buds as you harvest up the plants to give sprouts room to grow.
Harvest plants continually for 6 to 8 weeks.
Once buds form, if temperatures are beginning to climb, or if you want to harvest all the Brussels sprouts at once, pinch off the rosette (growing tip at the top of the plant) about a month before the desired harvest. This directs the plant’s energy to increase the size of the buds, and they will develop all at once.
Sprouts are best eaten fresh right out of the garden. Once picked, Brussels sprouts flavor declines as sugars turn to starch.
If not eating the sprouts right away, store them covered in the refrigerator for up to 1 week and wait to wash them until ready to eat.