Broccoli plants are part of the cabbage family of plants (Brassicaceae). It is closely related to cauliflower, cabbage, kale, and collards. Most of these plants have a similar life cycle.
If you’re growing your own broccoli at home, it can be very helpful to know what to expect in the garden. So, in this article, I’ll share the main broccoli plant stages.
Most types share the same growth pattern, but there are some differences. Your expected harvest window, the appearance of the heads, and the likelihood of the plants bolting are all varied based on the broccoli variety.
1. Seedling Stage
The first stage of broccoli growth is the seedling stage. This period lasts from initial germination, through the first 3-4 weeks of a plant’s life.
It is important to get the timing right when planting broccoli seeds. The plants are very sensitive to hot weather, so they should be started in early spring or late summer (for fall harvest).
Broccoli seedlings are almost always started indoors in small cell trays. Then, after 3-4 weeks of growth, they are ready to be transplanted outdoors into the ground.
It is best to plant broccoli seeds directly in a fertile potting soil. During the seedling stage, keep your plants on the cool side if possible, ideally around 60-70°F. Give the seedlings plenty of light and good airflow through their seedling stage.
2. Growth Stage
After your broccoli seedlings have outgrown their seedling cells, it is time to transplant. At this point, the plants are entering the 2nd stage of growth, the growth (or vegetative) stage.
During the first few weeks after transplanting, it is normal for broccoli plants to seem “stunted.” The plant is busy forming strong roots underground, paving the way to a successful harvest.
It is crucial to avoid overly hot temperatures as your broccoli plants grow. If you are growing in the spring, make sure to plant early enough, and grow varieties that are heat tolerant to best results.
After a few weeks, your broccoli plants should grow a large canopy of leaves and a thick main stem.
Note: It is normal for the broccoli stem to bend over and lay on the soil. The vegetation will adjust and grow upright over time!
3. Crowning Stage
About 8-10 weeks after transplanting, most broccoli plants should begin forming a crown. This is the part of broccoli that is eaten, so the harvest window is approaching.
The broccoli head is actually small clusters of unopened flowers. These are also known as florets, and the ideal time to harvest your broccoli is when the heads are still tight.
Tip: Cut off your broccoli just below the head. Each plant may produce secondary heads from the lower nodes on the plant, giving you another harvest of smaller crowns.
If you wait too long, or it gets too hot, your plants may enter the next stage of growth. Avoid waiting too long and harvest your broccoli before the flowers begin to swell up and open.
4. Flowering Stage
Shortly after a broccoli crown forms, its blooms will begin to swell and open up. Broccoli flowers are yellow or white (depending on the type).
Like other warm-weather crops, broccoli flowers will eventually form seeds. When the mature seeds fall and germinate, this completes the life cycle of broccoli plants.
If your plants are living in high heat, the crowns may open up their flowers earlier than desired. This is the top reason that broccoli plants fail in the garden.
Over time, the flower stems will elongate, growing to well over 3′ tall if left alone. While opened broccoli flowers are still edible, they will have a bitter taste.
Why is my broccoli bolting early?
The flowering stage can be accelerated by hot weather (above 85°F or so for most cultivars). It is most common for spring-planted broccoli to flower pre-maturely. If you consistently have bolted broccoli, consider planting broccoli for a fall harvest instead of summer.
Another trigger for early bolting is an increased day length. So, if your broccoli was planted too late in the season or you live in a place with longer days, it may cause your plants to bolt.
You can avoid bolted broccoli by planting in the summer for a fall harvest, shading the plants in the summer, and harvesting early.
Why Is My Broccoli Not Forming A Head?
Aside from early bolting, broccoli has just one other common issue: not forming a head. There are a couple of reasons this may be happening.
- Hot weather. Again, hot weather may be the cause of your broccoli not forming a head. If your plants are still in the growth stage, the heat can cause your plants to never form a head. If temperatures cool off, they may still form a head later. If your plants have begun forming a head already, high heat is more likely to cause bolting.
- Too much nitrogen in the soil. An over-abundance of nitrogen can cause broccoli plants to form lots of leafy growth, but later flowering.
Make sure your broccoli transplants have plenty of airflow and a cool temperature. You can shade the plants with shade cloth if you are expecting an early heatwave.
When to Harvest Broccoli Heads
Broccoli is best harvested when the central head is tight. This is the perfect time to get the best flavor and most attractive broccoli heads. If the florets are beginning to swell or open up, harvest immediately.
Do not pull up the plants after harvesting! Most broccoli varieties will send up more side shoots with smaller heads over the following weeks.
Best Broccoli Varieties
There are countless cultivars of broccoli to try growing. Some are better suited for tropical climates (like southern Florida, while others grow best as summer-planted crop. Here are a few great varieties:
- Belstar. This variety produces very tight heads that makes them very attractive and marketable. It is well-adapted to a variety of regions, and can be grown for a summer or fall-harvested crop.
- Kariba. If you’re looking for a great cold-tolerant broccoli, try this one out. It is most suitable for fall and winter harvested plantings.
- Burgundy broccoli. This purple pigmented broccoli is gorgeous and nutritional. This variety does not produce a large main head, but instead is grown for its abundant smaller side-shoots.
I hope this article helps you understand the broccoli growing stages and what to expect in your garden. Broccoli and cauliflower can be tricky plants to master, but if you focus on proper timing and variety selection, you are sure to find success!