Determining when to harvest broccoli from a home garden is both an art and a science. It’s a bit of a Goldilocks story, if I’m honest. Harvest too soon and the heads are small and dense. But if you wait too long to harvest, you’ll end up with a loose head that has gone to flower, and it may even taste bitter. If you harvest broccoli when the timing is just right, however, the flavor will be at its peak. Read on to learn when to pick broccoli based on several different factors.
When can I pick broccoli?
Broccoli heads picked at the right time are filled with vitamins and minerals, such as vitamin A, vitamin C, and calcium. The texture when raw is crisp and firm. When cooked, ripe broccoli is bright green and flavorful. There are two stages of broccoli growth that can be harvested. The first is when the plant has produced a main head. This is the primary cluster of flower buds that forms at the center of the rosette of leaves. The second stage of harvest happens later in the season, when the tender side shoots are ready for picking. Let’s discuss how to know when to harvest broccoli in both stages. This information pertains to both broccoli plants grown in the ground and those grown in pots.
How planting time influences when to harvest broccoli
Broccoli is a cool-season crop, which means it needs to be planted when the weather is still cool. For most growing zones and climates, broccoli plants are transplanted out into the garden 4 to 6 weeks before your expected last frost date. This gives the plants plenty of time to mature and produce their edible flower buds before hot weather arrives. Here in my Pennsylvania garden, our last expected spring frost date is May 15th, so my broccoli plants are planted into my beds sometime between April 1st and April 15th. Don’t worry about potential cold weather. Broccoli plants tolerate spring frosts and are cool-weather champs.
If you forget, or you miss this ideal planting window, don’t fret. You can set out transplants anytime in early spring really. Just be aware that transplants planted later in the spring risk being stressed by hot weather and they may only produce a button-sized head (called buttoning). When this happens, it’s a bummer, but sometimes Mother Nature decides to usher summer temperatures in a bit earlier than usual and there’s little we can do.
When growing broccoli, there are several other clues to watch for that signal when it’s time to harvest your crop.
When to harvest broccoli based on the date
The first thing to consider in determining when to harvest broccoli is the date. Most broccoli varieties mature between 60 and 70 days after the broccoli seeds sprout. (Some varieties, such as ‘Green Comet’, mature faster than that, so you should always check the seed packet for the exact number of days to maturity for each different variety.) If you start seeds yourself, that means you should begin to look for signs that the heads of broccoli are ready to pick about two months after you sow seeds and germination occurs. If you are purchasing transplants, they are likely already between 4 and 6 weeks old when you bring them home. Start checking the plants for harvest readiness about a month after planting.
Growing conditions, such as soil and air temperatures and whether the plants are in full sun or partial shade, can influence the maturation process, of course. But these dates are a good indicator of when you should start checking.
(Here’s info on how to grow broccoli from seed if you would like more information on the topic.)
When to harvest broccoli based on the variety
There are dozens of different varieties of broccoli, each with a slightly different taste and growth habit. Many gardeners have clear favorites, but I don’t. Some years I grow heirloom types, like ‘Calabrese’ or ‘Di Cicccio’, while other years I grow hybrids like ‘Packman’ or ‘Green Goliath’. Every broccoli variety I’ve grown over the years has a strong stem and beautiful green leaves. What varies between varieties tends to be the density of the flower buds and the size of the head. As mentioned earlier, check the days to maturity for each different variety you grow to determine when to harvest broccoli by its type.
When to harvest broccoli based on the head size
Beyond the days to maturity, you can also base your picking date on the size of the main head. Aim for densely packed buds that are solid green. Most varieties produce heads that are 6 to 8 inches across on average, while others are slightly larger or smaller.
If you planted too late and the head goes from a small button size straight to yellow flowers without fattening up, the weather was too hot or the plants were somehow stressed as seedlings or young transplants. Keep the soil moisture level consistent throughout the entire growing season and plant broccoli only in cool weather to avoid buttoning.
How to harvest broccoli
When you’ve determined your broccoli is ready for harvest, use a sharp knife to cut the head from the stalk. If the plant is well-watered, you may even be able to snap the head off with your hand. When you harvest, leave the rest of the plant intact. Many varieties will produce edible side shoots all summer long (more on this process in the next section).
Store broccoli in plastic bags in the crisper drawer of the refrigerator. You can also blanch it in boiling water for 2 minutes followed immediately by an ice water bath. Then pack the blanched broccoli in zipper-top plastic bags and freeze it for later use.
Harvesting broccoli side shoots all summer long
After the main head is cut, the nodes of most broccoli plants will form new flower stalks. These side shoots are tasty and prolific, though some varieties produce more side shoots than others. To maximize side shoot production, add plenty of organic matter such as compost to the soil prior to planting, and mulch the plants with straw or shredded leaves to reduce competition from weeds throughout the growing season.
It’s also essential that the plants stay well-watered throughout the entire growing season in order to support optimum side shoot production. Many years I harvest more broccoli via side shoots than I do via the main heads. At the very least, the side shoots from 4 to 6 plants will provide enough for a daily salad or an occasional pot of broccoli soup.
What happens when broccoli goes to flower
If you miss the harvest window completely, the buds that comprise the broccoli head will develop into yellow florets. The blooming flower stalks and florets are still edible, but they often turn bitter. Broccoli is an annual plant that completes its lifecycle in a single growing season so those flowers will go on to develop into seeds if insect pollination is successful.
You can save the seeds to plant again next year, but you might end up with a total surprise. Broccoli plants readily cross-pollinate not only with other varieties of broccoli, but also with other members of the brassica family, including kale, collards, kohlrabi, Brussels sprouts, and others. This means that if any of these plants are in flower at the same time as the broccoli, their genes could mix and the plants you grow from the saved seeds will be a surprise. I find it’s better to plant purchased seeds each season to ensure seed purity and productive plants.
Potential broccoli growing problems
Protecting broccoli plants from potential troubles is essential for a good harvest. While broccoli is easy to grow during the cool season, it’s not without its problems. Here are some issues that may affect how to grow and harvest broccoli.
- Caterpillars: There are several different pest caterpillars that use broccoli as a host plant, including cabbage loopers and cabbage worms. Handpick these green caterpillars whenever you spot them or cover plants with floating row cover. Large infestations can be managed organically with applications of Bacillus thuringiensis (Bt).
- Aphids: These tiny, pear-shaped insects are sometimes found clustered on the leaves or roots of broccoli plants. They are a common pest of the vegetable garden, but they seldom do significant damage. I let the ladybugs and lacewings take care of any aphids that arrive in my garden, though a sharp stream of water from the hose will easily dislodge them if necessary.
- Nutritional issues: Poor soil fertility and excessive levels of soil nitrogen can impact broccoli production. If you add nitrogen fertilizer to the garden before planting broccoli, you could end up with a lot of leaves and a very small head of broccoli. Lots of nitrogen also creates succulent tender growth that is welcoming to pests. Choose a complete organic vegetable fertilizer that either contains an equal amount of nitrogen, phosphorus, and potassium (N-P-K) or one that’s slightly higher in phosphorous which is used by the plant to form flowers, fruits, and healthy roots.
Try growing broccoli in the fall
While broccoli is best known as an early spring crop, in some climates you can also grow it in the fall. Plant transplants about 8 to 10 weeks before your first expected fall frost and cover the plants with a lightweight row cover if heavy frosts are predicted before harvest.
If you haven’t grown broccoli before, I encourage you to give it a try. Now that you know when to harvest broccoli and how to do it right, you’re fully prepared for success.
For more on growing broccoli and other spring vegetables, please visit the following articles:
- How to start broccoli seeds
- Spinach harvesting tips
- Growing Brussels sprouts from seed to harvest
- How to grow broccoli microgreens
- When to harvest carrots
- Picking beets from the garden