When to Harvest Broccoli

Why timing matters

The part of broccoli you eat is a cluster of unopened flower buds. Once the buds begin to open, the head loosens and yellow flowers appear, and Utah State notes that open heads are poorer in quality. There is no benefit in waiting for a bigger head if the buds are starting to open, so the harvest window is set by the buds, not by the calendar.

How many days to expect

From transplanting, most varieties are ready in about 50 to 75 days. Extension figures vary: Maryland gives 55 to 65 days, Iowa State 60 to 75 and Clemson 50 to 90 depending on variety. UF/IFAS lists 75 to 90 days from seed. Fall crops take longer than spring crops, according to Maryland, and the University of Arizona allows 90 to 100 days from transplants for the Phoenix area’s winter season. Seed packets give a maturity figure for each variety; start checking as that date approaches.

Signs a head is ready

• Firm and compact. The head feels solid and the buds are packed tightly together.
• Buds closed and green. No yellow petals are visible anywhere on the head. Iowa State describes a mature head as tight and blue-green.
• Full size for the variety. Clemson and Penn State give 3 to 6 inches across, Maryland 3 to 8 inches, Iowa State about 6 to 7 inches and Wisconsin 4 to 6 inches.

Hot weather shortens the window. Utah State notes that heads open and flower early when plants run short of water in hot weather, so check often during a warm spell.

How to cut

Use a sharp knife and cut the main stem below the head. Clemson and Utah State leave about 6 inches of stem on the head, Maryland 6 to 8 inches, and Wisconsin about 4 inches. Iowa State simply cuts just below the head.

Get the head into the refrigerator soon. University of Wisconsin Extension points out that broccoli respires quickly after cutting and deteriorates unless it is cooled promptly.

Side shoots

After the central head is cut, most varieties send up smaller heads from the leaf joints along the stem. Iowa State puts them at about 1 to 3 inches across, Penn State at up to 2 to 3 inches, and Utah State describes shoots 3 to 6 inches long. Maryland recommends cutting them over the following weeks as they develop, before they flower.

To keep side shoots coming, keep watering and give a light side-dressing of nitrogen after the main harvest, as both Utah State and Maryland advise. Some varieties are better at this than others: University of Wisconsin Extension singles out Green Comet for a substantial second cutting, and Clemson notes that Packman produces many side shoots.

Overwintering sprouting broccoli

In mild maritime climates west of the Cascades, overwintering sprouting broccoli is harvested from late winter into spring. Oregon State University’s PNW 548 says harvest ends when petals emerge or the flower stalks lengthen, the same signal as for heading broccoli.

Storage

Cool broccoli quickly after cutting and keep it cold and humid. At 32°F and 95 percent relative humidity, Utah State gives 1 to 2 weeks and Maryland 10 to 14 days. In a home refrigerator, store it in a perforated plastic bag; Iowa State gives 10 to 14 days, Clemson up to a week. Blanch and freeze any surplus.

Utah State’s rule of thumb for planning is 3 to 5 plants per person for fresh eating, plus 5 to 10 more if you plan to freeze.