Brassicas (Cruciferae family)
They are variously refered to as Cole Crops, Brassicas, Crucifers and all are highest in Vitamin A and calcium (only spinach--the chenopodiaceae family-- is higher). Collards are a Southern green and not as well known in NH. Cooked collards and kale are more nutritious when frozen first. See also Growing Greens and Growing Oriental Greens.
Greens like mustard and kale can tolerate some freezing temperatures better than broccoli and collards (a Southern green), so they might be seeded a little earlier. Constant outdoor temperatures below 40 or above 68 degrees may cause young brassica transplants to bolt. Greens need about 6 hours of full sun to grow properly. (Compare with tomatoes and peppers, which need 10 hours of full sun!) They also need temperatures between 40-68 degrees to form a head. So far, our luck growning broccoli in the spring has been dismal. We consider growing it as a fall crop, so seeding for transplants would begin July 20th, since, technically, the frost-free date is September 20th in Zone 4.
Consult the monthly archives in Garden Tips for generic information on growing or see Garden Links for sources.
The $64K question after 4 unsuccessful seasons in growing broccoli: should we try growing it as a fall crop to avoid the spring cutworm cycle or erratic weather fluctuations -- early or late frosts and early heat waves.
Our meadow gets intense sunlight and, coupled with severe drought for the past 5 years, the growing conditions for brassicas are not ideal. Add to that serious cutworm damage during their spring life cycle and we have a recipe for disaster!
Be on the alert for small white butterflies, the adult cabbage worm butterfly. Cover the plants with cloth fabric. Or, spray every 7-10 days with Bacillus thuringiensis (Bt). See the note in Pepper Bytes in the June Archive about cutworms, another broccoli pest.
See June Archive for transplanting tips.
Only one of about 7 broccoli planted in 2002 survived the cutworm invasion. (Our neighbor's broccoli matured beautifully, only to be decimated overnight by a critter he suspects to be woodchucks.)
Pak (Bok) Choi and Chinese Cabbage are even more sensitive to heat, especially Chinese Cabbage, but can be seeded in Zone 4-5 early in the month for a fall crop.
Warmer zone gardeners can seed broccoli and Brussels sprouts directly in the soil. Seed after a rain. Virginia Tech Extension recommends planting in a shallow trench and covering seeds twice as deeply as spring seeding to conserve moisture.
All crucifers contain bitter chemicals called glucosinolates--what gives mustard its "zing." Some like savoy cabbages have more and others, e.g., red cabbage, have less. (Red cabbage is also less attractive to caterpillars.)
Brassicas are also chock full of nutrients. One stalk of cooked broccoli contains more than the daily vitamin A requirement, nearly 4 times the vitamin C allotment, 33% of required riboflavin, and 15% of necessary vitamin B 6. (Broccoli leaves have more vitamins than the heads, so cook them too.) Kale has twice the daily requirements of vitamins A and C.
Unlike tomatoes and squash, which have long tap roots that can dig deep for moisture, the roots of the cabbage family are shallow and fibrous. They require evenly moist soil for good production.
If worms are still on the harvested plant, soak them for 20 minutes in cold water. That will drive them out without affecting the flavor.
The sign of an accomplished gardener, or, for that matter, a local farmer, is to have lettuce available about the time the slicing tomatoes and cucumbers are ripened, and greens available when winter squash and pumpkins are ready.
One local greens grower seemed surprised to learn that this year. He has been unable keep up with the demand! For a Zone 4-5 gardener/farmer, greens and lettuce seeding should have started around mid-late June.
Making lemonade out of lemons: some of the vacant pepper spots freed up by cutworm damage were used to plant some fall sets of bok choi, Chinese cabbage, and Mizuna, an Asian green.
To get more vitamins out of your vegetables, keep the outer leaves on your cabbage heads. They are high in vitamin C. Harvest some green leaves with broccoli heads and stalks; the leaves have more vitamin A than the head and are richer in vitamin C, too.
Spring-planted kale is still producing edible greens.
We begin harvesting leaves from summer seedings of lettuce and mizuna (oriental greens), transplanted into the garden around August.
Scouting continues for cabbage worms and spray with Bt at first sighting.
Fall crop seedlings are coming into their own. Chinese cabbage, pak choi, Tatsoi, and other Asian greens prefer cool weather. Kale and Brussels sprouts not only prefer cook weather, they can be harvested after several frosts or even longer if mulched well.