Now that cooler weather should be on its way, you may think that the vegetable gardening season is over. Think again. There are plenty of “brassicas”–broccoli, cauliflower and Brussels sprouts–that prosper during cool, damp days and even taste better when touched by a little frost.
“Many people don’t realize that you can grow these plants,” says Audrey Van Dellen of Roger’s Gardens in Corona del Mar. “People think they’re too complicated to grow, but that isn’t true. They do very well and can produce a great deal. One Brussels sprout plant can bear 100 or more sprouts.”
Broccoli, cauliflower and Brussels sprouts are a part of the cabbage family and now is the time to plant them. Nurseries are stocking seedlings that will be ready for harvest 60 to 80 days after planting. Seeds require an extra 30 days.
When choosing plants in the nursery, Ken Denham, a member of the Organic Gardening Club of Orange County, recommends that gardeners “pop the plant out of the container and check to make sure it isn’t root-bound. If you see a few roots, that’s OK, but you don’t want the roots growing out of the bottom of the container. Root-bound plants have slowed down in the growth process and are hard to rejuvenate when you transplant them.”
When planting brassicas you shouldn’t have to add anything to alter your soil pH, because they all require about 6% to 7.5%. If the ground is hard and clay-like, add planting mix and compost.“I generally recommend 3 to 4 cubic feet of planting mix per 100 square feet,” says Chuck Bybee, manager of Armstrong Garden Center in Santa Ana.
You will also want to boost the nutrient level of the soil before planting.
“Brassicas are heavy nitrogen feeders,” Denham says. “To increase nitrogen in your soil, add organic products such as blood meal or any type of aged manure such as guinea pig, steer, horse, rabbit or chicken.”
You can also buy granule or liquid fertilizers which have high nitrogen contents.
Although all three of these plants are very similar in appearance and growth habits, they each have individual needs that you should keep in mind.
“Broccoli is one of the easiest brassicas to grow,” Bybee says. “It is more heat tolerant and tends to bolt less than Brussels sprouts or cauliflower.” (Bolting refers to the plant producing small yellow flowers. When this happens the taste of the vegetable suffers.)
Broccoli is grown for its cluster of green flower buds and tender stems. The plant grows about 3 feet tall with an equal spread. “The tip of the main stem develops the largest cluster of buds,” Van Dellen says. “This is usually about 6 inches in diameter when ready to harvest.”
Cut broccoli’s main head with a knife about 6 inches beneath the cluster of buds. The main head won’t come back, but the plant is through producing. It will grow smaller side shoots which can be harvested for another 8 to 10 weeks.
To keep broccoli productive, Van Dellen says to fertilize when the plant is 6 to 8 inches, 12 to 15 inches and 2 1/2 to 3 feet high. The fertilizer should have a 5-10-10 ratio of nitrogen, phosphorus and potassium.
Unlike broccoli, cauliflower produces only one head. Stagger plantings to keep a steady supply throughout the growing season.
Cauliflower is a little more difficult to grow than broccoli. “It likes a cooler season and shouldn’t be planted until hot weather has passed,” Bybee says.
This vegetable usually grows about 2 1/2 feet tall by 2 1/2 feet wide. “It also requires frequent fertilization every two to three weeks,” Van Dellen says. “Use a fertilizer that contains a 10-10-10 ratio. When applying the fertilizer be very careful, however, because cauliflower roots are close to the surface and easily injured.”
To get a nice white head of cauliflower, you must blanch it, which means shade it. When the head gets the size of a quarter, pull leaves from underneath up over the top of the head and secure them with a rubber band, twist tie or similar object. This will keep the sun from turning the head yellow or brown and affecting the taste. In two to three weeks, there should be a 4- to 6-inch head.Brussels sprouts, those bite-size morsels that look like small cabbages, are probably the most challenging of the three plants to grow. They also require cool weather, producing loose sprouts when the weather is warm.
The Brussels sprout plant grows very tall, reaching at least 2 feet and sometimes 3 to 4. The sprouts form along the stalk, developing at the base first and working their way up.
When harvesting, pick from the bottom up. Bybee suggests picking them when they are about an inch in diameter because if they get any larger the flavor isn’t as good. You can usually harvest Brussels sprouts for up to eight weeks.
Brussels sprouts require fertilization when they are 6 to 8 inches tall, 12 to 14 inches tall and again when sprouts form, according to Van Dellen. For this plant you will want a 5-10-10 fertilizer.
Be aware that there are a few pests that bother all of these plants, including cutworms, cabbage loopers and aphids.
Cutworms attack plants when they’re seedlings. “To protect young plants from this problem, slip a paper cup down over the plant and into the soil,” Van Dellen says. “This prevents the worms from getting to the stems. Cut out the bottom of the cup so that sun will get to the plant.”
Another pest is the cabbage looper. This comes from the white butterfly, which lays eggs that develop into green worms. Apply products such as Dipel or Attack that have an active ingredient known as BT which kills worms without posing any health problems for you.
Or, interplant brassicas with onions, shallots, chives, leeks, garlic and aromatic herbs such as dill, fennel and anise. These plants emit odors that deter butterflies.
Aphids can also be pesky, especially for Brussels sprouts. To control them, wash your plants off with a hard spray of water. According to Denham, brassicas thrive with overhead watering.To keep brassicas healthy, always keep them moist. A mulch such as straw will help keep moisture in and weeds out.
Although these are all cool-weather plants, they do require some sunlight during the day. Choose the planting location carefully.
“Brassicas need four to six hours of sun a day for at least five days a week,” Denham says. “Watch a location for a few days to see if it will fit these requirements.”
If you have limited space, grow these plants in large containers the size of whiskey barrels. Out of the three, broccoli will do the best.
