Leave broccoli plants in the ground after harvesting the main head to allow side shoots to develop.

If you planted broccoli plants in late August or early September you should have heads ready or almost ready for harvest. The broccoli head is actually a collection of flower buds. Heads are ready to harvest when they reach 4″-8″ across (some varieties form larger heads that others) and the individual buds are plump but still dark green. If your broccoli head starts turning yellow you have waited too late – the flowers have started to open. It is still edible, but may not taste as good.

After you harvest the main head, leave the plants in the garden. They will produce lots of side shoots of mini-broccoli heads that will extend the harvest season for several weeks. Look for side shoots to form below where the main head was cut, at the point where leaves grow from the main stem. (Note: Cauliflower and cabbage will not form side shoots – after the main head is harvested you should pull these plants out of the garden.) If temperatures stay mild broccoli could keep producing side shoots for several weeks – especially varieties like ‘Italian Sprouting’ (also known as calabrese) which have been developed to produce lots of side shoots over a long season.

Broccoli plants will usually tolerate temperatures as low as 26 degrees with little damage. Sudden changes in temperature can be more damaging. For example, if several days of temperatures in the upper 60’s or low 70’s are followed by a plunge into the upper 20’s plants will be more severely damaged than if we had several days in the 40’s or 50’s with night time temps in the mid 20’s. Also, plants that have been heavily fertilized with nitrogen, which encourages lush, tender growth, will be more heavily damaged by cold than those fertilized at light to moderate levels.

Light frost will not damage broccoli, but plants should be covered when temperatures fall below 25 degrees.

Broccoli heads are more frost sensitive than broccoli plants. Heavy frost may damage the heads, causing the florets to become mushy. If this happens, cut the head off and compost it, but leave plants in the ground. Side shoots will still likely form. Cold weather may also cause broccoli heads and leaves to take on a blue or purplish color. This is just a reaction to cold temperatures and not a sign of damage or loss of quality. To protect broccoli heads that are almost ready to harvest when temperatures are expected to dip into the upper 20’s or below, cover plants overnight with floating row cover or an old blanket. Remember to remove protective coverings in the morning.

Here is an additional tip for broccoli – you can eat the leaves as well as the broccoli head. Other vegetables with edible leaves that you may not be aware of include beets (a relative of Swiss chard) and turnip (some varieties are grown just for the leaves).

The thing you have to be careful of when harvesting leaves of vegetables that produce an edible root, seed pod, or flower head (such as broccoli and cauliflower) is not to remove too many leaves. The leaves are what feed the plant. Fertilizers provide plants nutrients they need, but true plant food is made in the leaves from sunlight through the process of photosynthesis. Remove too many leaves and you limit the plant’s ability to feed itself, which results in smaller roots or fewer/smaller flowers/seed pods (this is why plants that receive a lot of leaf damage by insects or disease are often stunted) . When harvesting leaves of plants you are growing for other edible parts, only harvest a few at a time, and once a week at most.

Once you harvest your main broccoli head, you can harvest as many leaves as you like. This may slightly reduce the amount of side sprouts you get. If you really develop a taste for broccoli leaves you may want to try growing leaf broccoli, also known as Spigarello. This is a traditional Italian crop I grew for the first time last fall. It grows like a kale plant but the leaves look more like broccoli and are sweeter than kale. Spigarello is a cool season crop that can be grown from seed in the fall or spring.

Learn More

• Clemson Extension fact sheet, Growing Broccoli: http://www.clemson.edu/extension/hgic/plants/vegetables/crops/hgic1301.html.

Visit your local Cooperative Extension office to learn more about gardening and landscape care. Go to https://www.ces.ncsu.edu/local-county-center/ to find your county Extension center.

• If you live in Pender County, call 910-259-1235
• In New Hanover County, call 910-798-7660
• In Brunswick County, call 910-253-2610
• In Onslow County, call 910-455-5873
• In Duplin County, call 910-296-2143