Broccoli Plant Growing Stages, From Seed to Harvest

Is it your first time growing broccoli and you’re unsure what it’s supposed to look like? Let’s look at all of the broccoli plant growing stages, from seed to harvest, and we’ll troubleshoot any growing problems along the way.

Broccoli Plant Growing Stages

Can you believe that there are ten broccoli plant growing stages? We’ll cover each one of these in detail:

1. Seed Stage
2. Germination Stage
3. Seedling Stage
4. Transplant Stage
5. Growing / Vegetative stage
6. Heading Stage
7. Harvesting Stage
8. Side shoots Stage
9. Flowering Stage
10. Going-to-seed Stage

Planting Your Broccoli Seeds

Broccoli seeds are relatively small, round, and almost black. Don’t mix them up with other brassica seeds because they all look the same. Cauliflower, Cabbage, Collards, and Brussel Sprouts are all cole crops with seeds that look exactly alike.

Broccoli is a cold hardy vegetable plant, meaning it can withstand cold temperatures. I like to start my seeds indoors in Fall, about 6 weeks before my first average frost date. This allows me to grow broccoli plants throughout the winter and into spring since our summers are much too hot for them.

If you live in a colder climate, start seeds indoors in winter, about 4-6 weeks before your last frost date. 

You can direct-sow broccoli seeds if you like, but I find that they’re pretty susceptible to pest pressure until they reach the transplant and growing stages. Cut worms tend to take them out when I direct-sow.

To start seeds, use our COMPLETE GUIDE TO SEED STARTING FOR FULL INSTRUCTIONS. To put it simply, use a quality soil, a container, good seeds, and a little water. Broccoli seeds only need to be buried in your soil about 1/8-1/4 inch deep. Pack the moistened soil over the top of the seed and wait for germination. Most importantly, don’t let the soil dry out while waiting for your seeds to sprout.

Seed Germination Stage

​Germination is just a scientific word for sprouting. When the seed opens and the tiny plant emerges from the soil, seeking light to grow, you have germination. Broccoli, a cool weather loving plant, germinates best in temperatures around 70°F. It generally takes 7-10 days to see broccoli germinate.

In this first stage, you don’t need to feed the soil. Just keep it moistened and use grow lights if you’re starting seeds indoors.

Broccoli Seedlings

In the seedling stage, the baby plants will have their first set of leaves, the cotyledons. The seed that you planted contained enough energy to produce these first leaves for the plant. These cotyledons do not resemble the plant’s true leaves that will grow next. They serve to give the plant something to use for photosynthesis.

Once the first set of true leaves grow in, you can pinch off the cotyledons as the plant is no longer using them. They’ll die back anyway. 

Now watch for any sign of nutrient deficiency. Yellowing of leaves would indicate lack of nitrogen. A purple tinge is a sign of low phosphorous. If you experience either of these in your seedlings, water them with a balanced liquid fertilizer.

When to Transplant Seedlings

​The fourth of the broccoli plant growing stages is the transplant stage. You can move your broccoli transplants out to your garden beds after they’ve grown their second set of true leaves. This will be about 4 weeks after you started seeds. 

First, make sure you harden them off by giving them a little bit of time outside to acclimate to the natural outdoor elements. Then, increase the amount of time they spend outdoors a little each day for 4-6 days before transplanting.

​Mark out where you’ll place your young plants in the garden, giving them enough space to grow into mature plants. Most seed packs advise every 18-24 inches, but I like to plant intensively at every 12 inches. This works for me as long as I water and feed them well as the plants will have to compete more for nutrients.

Water your transplants well. Scoop some soil out of the garden bed, place your transplant in the hole, and add in some quality potting soil around your transplant. This helps ensure a great start to it’s life. Pack the fertile soil back around the base of the plant and water it again. You can top dress the plant with a little fertilizer or compost at this time if you’d like.

Growing Stage

​During this time, the broccoli plants are in a growing or vegetative stage. They are simply growing into mature plants. You may think that nothing is happening, but I can assure you, they need to grow up before they can fruit.

Continue to water your plants regularly and watch for nutrient deficiencies. The occasional feeding with a light fertilizer or compost is a good idea to keep them going.

The most important thing that you need to watch for during this stage is pests, for example cabbage loopers. They are little brown moths that fly in at night and lay their eggs on the leaves of your plants. The eggs hatch and little green worms will decimate your cole crop in no time. Using row cover prevents an infestation. Spraying with bacillus thuringiensis (BT) will kill the cabbage looper and other soft-bodied creatures.

Head Formation

Next, is the crowning stage, when your plants will form the main head. This is actually a giant cluster of flower buds that we will harvest and eat. The broccoli heads will shoot up from the center of the plant. 

At first, you’ll see a tiny floret form down in the middle, but it will eventually grow upwards and form it’s main head, or crown. Depending on the variety, you may get flower heads that are 3-8″ in diameter.

Broccoli Harvesting Stage

Finally, the point we’ve all been waiting for, the broccoli harvest. You want to harvest the central head when it peaks, right before the buds open to flower. If you’ve begun spotting glimpses of yellow in the crown, go ahead and cut your broccoli crown because it’s getting ready to open.

You should be able to harvest your broccoli 55-65 days after transplanting your seedlings into the garden. Use a sharp knife on the main stalk for easier harvesting. I like to take as much stem as I can, all the way down to the leaves because the stem is edible too.

Side Shoots Stage

After you’ve harvested the main large head of broccoli, leave the plant in the garden bed. The main stem will scab over where you cut the crown.

Continue to care for the plant with water and fertilizer. Soon, your broccoli plant will begin to grow side shoots. On all sides of the main stalk, smaller heads will grow. This will give you a continuous harvest of broccoli florets while the plant continues to thrive.

Flowering Stage

Eventually, the weather will warm up too much for your cool-season crop, and your plant will flower. Any heads that remain on your plant will open up to reveal little yellow flowers. The pollinators love these flowers so if I have the space to leave them, I will. 

Broccoli flowers will then produce little seed pods. You can snip them off and eat them if you’d like, or let them fully mature and dry on the plant. If you choose the latter, be sure to save the seeds for the next growing season.

If your broccoli flowers before you harvest it, it’s still edible. However, it probably won’t carry a sweet flavor though like fresh, young broccoli does. 

Broccoli Total Growing Time

The total broccoli plant growing stages life cycle will generally last for around 100-120 days from seed to death of the plant. Heat, downy mildew, or cabbage worms are the top culprits to killing your broccoli plants.

​Your Best Broccoli

​To keep your broccoli plants thriving, make sure you offer them full sun, well-drained soil, and fertilize them throughout the growing season. They are big, leafy plants, therefore they need a lot of nitrogen. Blood meal is a favorite fertilizer for broccoli.

Control the most common broccoli pests with our ORGANIC PEST CONTROL RECOMMENDATIONS.

The best tasting broccoli will be those that received a very light frost. Cutting the heads while they remain on the smaller side will give you a milder flavor too.

​Different Varieties

​Some popular broccoli varieties are:

• Calabrese broccoli – heading kind that you usually see in the grocery store
• Belstar – my favorite hybrid, heat-tolerant variety. Grows large, tight crowns up to 8″ wide.
• Magic Green – sprouting variety that forms a smaller central head, but then several side shoots for a lengthy period of time.
• Waltham – heading broccoli that is open-pollinated, high production broccoli plant
• “Broccolini” – actually a hybrid plant that grows long, tender stalks with small florets giving mild flavor

All of these varieties will go through the same broccoli plant growing stages.

Troubleshooting Growing Broccoli

​The most common problems when growing broccoli are bolting, lack of crowns, and bug damage. Let’s go through each problem.

Why is My Broccoli Bolting?

Bolting happens once warm weather strikes, and this can happen at any of the broccoli plant growing stages. Trust me, I live in Florida, so I know the frustration that comes with brassica plants bolting. Our winters are sprinkled with warm spells when temperatures reach the low 80s°F, and our broccoli decides to flower. 

Offering shade during these warm periods helps tremendously. Most importantly, choose a variety that can withstand warmer days, like Belstar.

Why is My Broccoli Not Forming a Crown?

There are a couple of possibilities for your broccoli plant to not form a head or crown during the broccoli plant growing stages.

First, is it too hot or too cold? Broccoli plants like temperatures between 40°F-70°F to thrive. Too hot, and they’ll bolt to flower. Too cold, and they’ll button. Buttoning is when they just form several tiny heads. You can still harvest them, but it creates a real anti-climactic harvest for the home gardener.

Second, are your plants competing too much for nutrients and water? If they’re planted too close together, their roots won’t have room to reach out and the plants can’t take up nutrition. This causes the plants to become stunted, and a lack of head is the result.

​Third, a lack of phosphorus will keep broccoli plants from heading. Check the N-P-K formulation on the fertilizer that you’ve chosen. The middle “P” represent phosphorus, and is a good support for flowers and roots.

Last, did you plant in full sun? If not, I’d guess that your plants are stunted and stuck in the lengthy vegetative stage.

The good news is that you’ve gained some experience here, and you can do better next growing season. You also get to eat the leaves of the broccoli plants so all is not lost.​

What’s Eating My Broccoli?

​As already stated, cabbage loopers are the number one pest that eats up plants at any of the broccoli plant growing stages. BT is my go-to remedy for them and any other kind of worm eating my plants.

Another common pest that causes damage to broccoli plants are flea beetles. They are tiny little creatures that eat several holes in the leaves of your plants seemingly overnight. Spinosad is my organic pest control choice to treat for flea beetles.

Summary – Broccoli Plant Growing Stages

I hope that this gives you a better idea of what the broccoli plant growing stages should look like, and you’ve gained some helpful information about each stage. Now go take this insight and apply it to grow a little food of your own.

Happy Gardening!

Donna and her family have been homesteading for most of their 20+  years together in some shape or fashion. She currently lives on their 20 acre farm where they grow as much food as possible. What started as a just a few laying hens, has grown into large gardens, pastured poultry, pork, and lamb. They are continuously evolving their small farm to not suit their family’s needs, but also providing to their local community. Donna’s favorite part of the family farm is her self-built micro-dairy, where she gets to love on dairy cows while serving her local community. Milking, cheesemaking, and processing dairy have become the soul of their homestead and the center of their farm.