Broccoli (Brassica oleracea var. italica)
GROWING SUMMARY​
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Onions are frost hardy and germinate best between
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Timing:
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Direct Seeding
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Growing Seedlings
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Bed Preparation
Raised beds
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Plant Spacing
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Irrigation
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Pests and Diseases
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Harvesting
November – January depending on variety & location
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GROWING SUMMARY​
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Broccoli belongs to the cabbage family but is not grown for the leafy heads rather for the large, tight terminal heads of green flower buds on top of thick, edible stems.
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Broccoli is not frost tender and can be grown all year round.
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Like all the large brassicas broccoli needs rich, well fertilised soil and plenty of space. 300-500mm between the plants.
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Timing is dependant on variety and with the right types broccoli can be grown year round.
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Broccoli is best raised as a seedling and then transplanted into the garden as a well established seedling. The young plants germinate quickly and grow fast and are often quite "leggy". It is very important to plant them really deep when they go into the garden. The leaves should be at soil level with no stem sticking out.
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The plants grow rapidly, quickly getting to the stage when they cover the beds. A couple of quick hoeings in the early stages or a heavy mulch is all that is necessary to keep them weed free.
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Harvest when the heads are fully developed but still tight. They florets can still be enjoyed if they are slightly open, however at this stage they can suddenly run to flower. All varieties of broccoli will produce side shoots after the main head has been picked.
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Cabbage moths and butterflies are a problem in summer but can be easily controlled organically with Dipel (Bacillus thuringiensis) or by using some sort of exclusion netting.
VARIETIES​
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Broccoli can be harvested most of the year in temperate climates, the trick is to sow the right variety at the right time.
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Winter heading varieties - These are harvested in winter, not grown in winter. There are lots to choose from. Extend your picking over winter by planting some fast and consistent hybrids plus a few old fashioned favourites.
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Summer heading varieties - quick growing and tend to head up all at once. Plant several successions.
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Sprouting broccoli - Italian Calibrese types and purple sprouting produce lots of little heads over a long period.
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Chinese Broccoli (Kailan) - Grown for its long stems as well as the flowers
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Broccolini - a modern cross between broccoli and Chinese brocdoly first developed in Japan. grow in cooler weather
MORE INFORMATION
Timing
All members of the cabbage family run to seed in early spring but with broccoli you are eating the flower head so this does not matter. That said if you want big heads in the middle of winter make sure you plant the seed in January or February transplanting 4-6 weeks later. You need to get the plants really well established before the cold weather sets in.
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Close examination of seed catalogues and the back of seed packets will ensure that you are planting the appropriate variety.
The great thing about broccoli is that many varieties will not only give you a big showy head, they will also provide a succession of smaller side shoots that are equally good. If small side shoots are all that you want the Italian 'Calibrese' and 'Purple Sprouting' varieties produce them in profusion. Chinese broccoli (Kailan) is another type that does not produce large heads, it is grown for the long stems as well as the flowers.
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Pest Control
The worst pests of broccoli are the cabbage white butterflies that hover around the plants all summer. With the big leafy cabbage family members the caterpillars are easy to spot but not so with broccoli where they are able to hide in the florets. There is nothing that will put people (particularly children) off this tasty, nutritious vegetable than finding a cooked caterpillar on their plate.
You just have to be vigilant in the warmer months. If you see even one white butterfly there will be eggs and caterpillars. The eggs are easy to spot, they are small, round and yellow and you will find them on the underside of the leaves. If you only have a few plants it is easy to squash the eggs off with your thumb. This is easy if you only have a few plants and they are small. The best solution is to check all your seedlings for eggs when you plant them then put some sort of insect exclusion cover over the top of the plants. If the butterflies can't get on the leaves they can't lay eggs. Another great biological control is Dipel, a bacterial poison specific to caterpillars and which will not harm all the wonderful beneficial insects. The easiest option of all is to not grow broccoli in summer. There are so many great summer vegetables save broccoli for winter a winter treat and you will only have to worry about these pests in the early stages when the plants are getting established.
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Weed Management
​​Because of the wide plant spacing broccoli is easy to hoe when it is small. It is also a great candidate for heavy mulching. When using mulch be vigilant with slug control because slugs love young Brassica plants.
Once the plants are well established weed problems disappear. The large shady leaves protect the soil and when the outer leaves die off they put small amounts of germination suppressant chemicals into the soil.