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University
of Rhode Island GreenShare Factsheets
Broccoli
& Cauliflower
Broccoli
and cauliflower both belong to the cabbage, or cole, family. Other
commonly grown cole crops include brussels sprouts, collards, kale,
kohlrabi and cabbage. Cole
crops are cool-weather vegetables, growing best when daytime temperatures
are between 65 and 80 degrees F. Cauliflower is more sensitive to
hot weather than broccoli. In the Northeast, broccoli is grown as
a spring and fall crop, while cauliflower does best when planted
in mid-summer for a fall harvest. Both
broccoli and cauliflower tend to do better when set out as transplants
rather than planted from seed. It is important to use sturdy transplants
that will become established quickly.
All of the cole crops grow well in reasonably fertile, well-drained,
moist soils with plenty of added organic matter. A mulch will help
keep the ground cool and moist. The pH should be between 6.0 and
7.0 for optimum growth. A pH within this range will discourage clubroot
disease and maximize nutrient availability. Fertilizer
and lime are best applied using the results of a soil test as a
guide. As a general guideline, 2 to 3 pounds of 8-16-16 fertilizer
applied uniformly over 100 square feet of garden area is suggested.
Work the fertilizer thoroughly into the soil about two weeks before
planting time.
A liquid starter fertilizer applied to the transplants at time of
planting will help establishment. Apply a half pint of a 20-20-20
or similar solution to each plant, preparing the fertilizer according
to label directions.
All cole crops are frost tolerant. Broccoli transplants may be set
out in the garden as early as April 1. For a fall cauliflower crop,
set out transplants on July 1. Broccoli
may be spaced 18 inches apart in the row with 24 inches between
rows. Cauliflower plants should be placed 24 inches apart in the
row with 30 inches between rows. As
cauliflower plants begin to mature and the head, or curd, starts
to form, gather together and tie the leaves over the curd with
soft
twine or tape. This "blanching" is required to ensure that the
curd will be white and tender at harvest. There are some 'self-blanching'
types available where the leaves curl naturally over the head when
grown in cool weather (some tying of the leaves may still be necessary,
however). An
even moisture supply is needed for transplants to become established
and to produce good heads. As mentioned earlier, an organic mulch
will help keep soils cool and moist and suppress weed growth. Hand-pull
or use shallow cultivation if additional weed control becomes necessary.
Apply 1 to 1.5 inches of water per week if an equal amount of rainfall
does not occur. An additional side dressing of a nitrogen fertilizer
when the plants are well established may be desirable. Principle
insect and disease problems are the cabbage
looper, imported cabbage worm,
cabbage maggot, aphids, flea beetles,
blackleg, black rot, clubroot,
and yellows. See GreenShare Factsheets on specific pests or diseases
for information about cultural control recommendations.
Harvest the center green flower bud cluster of broccoli while the
buds are still tight and before any yellow petals begin to show.
Cut the central stem five to six inches below the head. Many cultivars
will continue producing bonus side shoots as long as a few leaves
are left on the plant, extending the harvest period for a month
or more. The
cauliflower curd, like the broccoli head, is actually a group of
tightly clustered white or purple flower buds. Harvest the curd
when it reaches the desired size but before the buds begin to separate,
about two months after transplanting. Cut the head so that at least
two wrapper leaves are present. Adapted
from Marianne Riofrio, Ohio State University Extension, 2000
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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