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Name: Jim
Status: educator
Grade: 6-8
Location: OH
Country: USA
Date: Summer 2011

Is broccoli a short or long day plant?

Cole crops are usually assumed to be long day plants. This indicates a need for long days (technically short nights!) to initiate flowering. For broccoli, however, the literature is more noncommittal. Some authorities have determined that it’s photoperiod insensitive. Temperature is considered more influential. Other scientists have found that long days accelerate maturation time. Finally, one paper I found said that broccoli responded very weakly to short days.

I think much of the confusion stems from differences in photoperiod sensitivity among varieties. Also remember that photoperiod also doesn’t necessarily work independently of other factors. Temperature can modify its impact.

Based on a preponderance of available information, I’d be inclined to say that broccoli is a facultative long day plant. Long days may accelerate development, but in their absence, it’ll flower regardless.

Dr. Tim Durham Department of Biological Sciences Florida Gulf Coast University


Anthony Brach Missouri Botanical Garden/Harvard University Herbaria

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