Extending the broccoli harvest

Since broccoli is a cold weather crop, meaning that it grows best in soil with temperatures between 65 F. and 75 F., the hot weather we are getting here in Boise is going to cause it to start to flower, also called plant bolt. Contrary to popular belief, hot weather will not cause bolting broccoli. What actually causes broccoli and other crops to bolt is hot soil.

So what do you do to prevent this for a longer broccoli harvest? A thick layer of mulch and frequent watering can help keep the roots cool and prevent broccoli from starting to flower or bolt.  Row covers or shade covers will also help keep the direct sun from the plants and soil, keeping the ground cool. Row covers are frequently used to keep cold weather crops producing longer. Since I’d like to harvest my broccoli for a few more weeks, I’ve initiated all of these measures.

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I planted my broccoli transplants around the middle of March this year. And since broccoli is a cut and come again vegetable, another excellent way to prevent broccoli flowers is to watch it carefully and harvest frequently. When you cut the main head, other smaller heads will grow and the side heads will take a little longer to bolt. This is what I picked today.


Romanesco broccoli, also known as Roman cauliflower, Broccolo Romanesco, Romanesque cauliflower or simply Romanesco, is an edible flower bud of the species Brassica oleracea. It is a unique Italian variety that produces a yellowish-green dense head that forms an unusual spiral pattern. Maturing about seventy-five to one hundred days after planting depending on variety. Romanesco develops multiple compact heads that may be individually snapped off as needed. Its unique growth pattern creates ornate twists from four-to-five-inch, light green heads.

Other than being incredibly beautiful and fun to photograph, Romanesco is supposed to have a distinct nutty flavor described as more intense than broccoli. It is said to taste like a cross between broccoli and cauliflower. I’ve been trying to grow Romanesco for several years and every year the heat or the aphids have prevented me from seeing this gorgeous Brassicaceae. Right now, each plant has one head that is about 2 to 2 ½ inch wide. I have mulched and covered these beauties in hopes of seeing a head that is at least four inches. As you can see in the image gallery below, one of the heads has already started to bolt. Preventative measures are now in place. I’m anxious for a taste test next week.

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