Broccoli is one of our favourite vegetables, not only for its flavour, but also for its versatility and calcium values. It is therefore a vegetable worthy of attention. For those of us wanting to grow vegetables for health reasons, this may be a new beginning.
With emphasis on buying within 100 Km and now the high cost of fuel, why not grow your own.
There are some key factors for growing broccoli successfully. For optimum flavour and nutrition, time your crop to mature in cool weather.
My personal preference is the hybrid blend (BR180) from West Coast Seeds, because of my continued success in my trials. All varieties in this blend make big side shoots that keep producing for four weeks. Some of these varieties grow faster, stretching the growing season for the home gardener. Do not throw away the runt seedlings as they mature later. I have enjoyed this blend for both early and fall crops.
For our garden the first sowing indoors under grow light is mid February, for setting out late March for a few days in a cold frame, then planted out providing some form of cloche for the first while if weather is cold.
The second sowing is done early June for planting out during a cool period in July. Too early planting or long periods of cold weather can cause the formation of ”button heads” At temperatures in excess of 250C the plants produce excessive leaf growth and fail to head up.
Young plants will withstand a light frost, but may get leaf burn, but will usually recover. Although Broccoli can be direct seeded for the fall crop, you will get the most from your garden and produce hardier plants from seedlings. The health of the transplant is important, too large or too old a seedling usually give you a lot of premature heading or buttoning.
Four-week-old seedlings with 2-4 leaves have the greatest chance of survival and high production.
Transplants kept too long in a seed flat are sure to fail. Seedlings with a purplish tinge are stressed and cause premature heading. Older transplants are weak, poor plants. Keep seedlings in the 16-18 degree Celsius range in the early stage of plant life to prevent vernalization.
Keep broccoli growing fast and even. In cold springs I work in a light dressing of organic fertilizer with a high first number to the soil and also add 450 grams per square meter canola meal to provide that even growth via slow release nitrogen.
Any disruption in nitrogen supply or moisture stress, which causes the checking of early vegetative growth, can trigger the onset of “buttoning”
Broccoli prefers a rich well-drained soil with ample nutrients, especially Calcium and Magnesium supplied by dolomite lime. Manure spread over the patch the fall before is of great benefit. Turn this under in the spring, three weeks before planting. The most critical time for nutrients is when broccoli plants are in their early stages of development. Side dressings of manure tea or fish emulsion are most beneficial at two to three weeks after transplanting. A second feeding one week before the center head is cut helps to stimulate vigourous side shoots.
Remember, given good soil fertility,head size is proportionate to the 18” spacing of the plants. Never try close spacing if you want side shoots. Only commercial growers plant closer for a onetime harvest. Two or three days are all the difference between mature or over mature broccoli.