Harvesting broccoli at the right time can be tricky, especially if the weather turns hot all of the sudden. Broccoli heads tend to bolt without warning when temperatures soar above eighty degrees. Once the heads start to flower, they are past the point of harvesting. The leaves and stems may still be salvageable, but the prized broccoli heads are lost.
I like to set my broccoli transplants out as early as possible, a couple of weeks before the last threat of frost and before pests are out in full force. I am usually looking to harvest the first broccoli heads by mid to late June. This year we had an early hot spell, and I was barely able to catch the broccoli heads in time before the yellow flowers shot up.
Days to harvest can vary depending on the variety and growing conditions. Look for heads to be well developed and compact. Once they start to spread and expand, the plant is preparing to bolt. The heads are still edible at this stage, but should be harvested and consumed as soon as possible. I’ve encountered plenty of broccoli heads at the grocery store with dry yellow tips that were caught just before flowering, so even the experts cut it close sometimes.
To harvest, cut the heads clean across, leaving several inches below the base. Most broccoli varieties will develop side shoots and smaller heads after the main head has been harvested. Broccoli leaves, stems, and stalks are edible and may be harvested at any time after the plant has matured. Leaves and stems can be steamed or roasted. For the stalks, I do a rough chop and add them to other raw vegetables in the juicer. One of my favorite juice recipes calls for broccoli stalks, carrots, ginger and lemon.
Broccoli heads are a favorite nesting place for many pests. I rinse off harvested heads with the sink sprayer as soon as I bring them in. Then I fill the sink with fresh water, add 2-3 tablespoons of salt and vinegar, and soak the broccoli heads for 30-60 minutes. Give the heads a thorough rinse before using.