Growing Broccoli

How To Grow Broccoli: A Step By Step Guide

Broccoli is one of those controversial vegetables. You either love it or hate it! I love it! Growing Broccoli in our garden every year is a requirement!

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Broccoli is a member of the Brassica or Brassicaceae Family and is related to cabbage, kohlrabi, brussels sprouts, kale, collards, and cauliflower. Broccoli is also a vegetable that is a little harder to grow so let’s learn more about broccoli and how to grow it successfully in your garden.

Where did Broccoli Come From?

Broccoli originated in the Mediterranean in the area we now call Tuscany. Broccoli was created from a cabbage relative by the Etruscans. There are historical references to broccoli as far back as 79 AD. Broccoli was used extensively throughout the history of Italy.

Broccoli started moving out of Italy in the 1500s and we start to see mentions of it in England and the United States in the 1700s.

However, broccoli didn’t gain popularity in North America until the 1920s, and it has now become one of the most popular vegetables we grow and eat.

Broccoli Nutrition Facts

Broccoli is loaded with nutrients. 1 cup of chopped broccoli has only 31 calories and almost no fat. The same cup of broccoli has 288 mg of potassium, 135% of your daily vitamin C, iron, calcium, vitamin b6, folic acid, and magnesium. It also contains 2.4 grams of fiber and surprisingly 2.6 grams of protein.

Broccoli shines when it comes to its content of phytochemicals, antioxidants, and other bioactive compounds. Sulforaphane is just one of those great compounds that has wonderful anti-inflammation and anti-cancer properties!

Broccoli is a Cool-Season Crop

Broccoli is considered a cool season crop. It will grow its best in temperatures below 75 degrees Fahrenheit (24 C). Once temperatures start to rise above that level broccoli quality will drop off quickly and the plant will often bolt to seed. So this means we traditionally plant broccoli in the early spring for an early summer harvest. Broccoli can be planted again in the late summer for a fall harvest.

Broccoli can tolerate a light frost, but a heavy frost and temperatures below freezing can damage your plants. So when nights get cold in both the spring and fall it is best to cover your plants with some fabric row covers.

The Best Soil and Conditions for Growing Broccoli

Broccoli will do best when planted in areas with full sun. Broccoli will appreciate at least 6 to 8 hours of sun per day.

It grows well in well-drained and fertile soil. Constantly work to improve your soil fertility by adding compost or well-aged manures to your soil before planting your broccoli seeds or plants. Broccoli grows best with a soil pH between 6 to 6.8 but will tolerate soils outside of that range.

If a soil test indicates a need you can add a high nitrogen fertilizer to your soil to help improve your crop. This is especially important when small broccoli heads first start to form.

You should avoid planting broccoli in areas that have had other Brassica family plants in the last four years. Crop rotation like this will help keep pest and disease problems at bay.

When to Plant Your Broccoli

Broccoli is traditionally planted using seedlings. This is because the growing season for broccoli is so short in both the spring and fall. Broccoli likes those temperatures in the 60s and 70s (F) (between 15 to 21 C) so we give them a head start by planting them indoors first. Planting using seedlings allows the plants to quickly mature outside before the warmer summer temperatures arrive. Temperatures above 80 F (26 C) will cause your broccoli plants to quickly bolt to seed.

Broccoli Plants are very tolerant of cold and frost. They will have no problems with light frosts and can even endure a few days of below-freezing temperatures. But extended cold spells will be hard on broccoli so you should plan on protecting your plants with a fabric row cover or hoop house.

When to plant Broccoli in the Spring?

We want to set our broccoli seedlings out in the garden about 3 to 4 weeks before our last frost date in the spring. So you should sow seedlings indoors about 10 to 12 weeks before your last frost date. This will give you strong 6 to 8-week-old transplants to go out in the garden in the spring. You can learn more about growing seedlings by downloading our FREE Seed Starting eBook at this link.

When to plant Broccoli in the Fall?

Fall transplants should be set out in the garden about 6 to 8 weeks before your first fall frost. This is usually in late July or August, depending on where you live. That is a rough time in the garden with lots of summer heat so plan on giving your fall broccoli some extra attention. Start seedlings indoors about 12 weeks before your first frost date.

Be sure to harden your transplants for about 7 days before planting them out in your garden. This adjustment period helps limit transplant shock.

Gardeners who live in more temperate climates may be able to directly sow broccoli seeds in the garden. Try to sow seeds late in the summer just as your temperatures are starting to cool.

Plant Spacing for Broccoli

Most broccoli varieties will get fairly large as harvest time approaches so you need to be sure to give your plants some space. Plants will get between 18 to 36 inches tall.

Give your plants 15 to 18 inches between each plant. This should give the plants the space they need as they mature. Broccoli appreciates a little space and air circulation to help keep diseases down.

That spacing is pretty far between plants which means early in the season there will be a lot of space between those plants. You can fill up that space with some quick-growing companion plants. Sowing plants like lettuce, arugula, mustard, or radishes in the spaces between your broccoli plants will use up that empty space. All of those crops will be ready for harvest in 30 to 45 days, just as the broccoli plants are getting larger and shading the crops planted below them.

Caring for Your Growing Broccoli Plants

Broccoli also needs plenty of water and will demand even more water as the broccoli heads are forming. Mulch around your plants with grass clippings, straw, or compost to help keep your soil moisture stable.

Drip irrigation works best for broccoli. A good deep soaking from a drip system will promote strong plant growth. Drip systems will also help you avoid some of the more common diseases in broccoli like powdery mildew or downy mildew. Drip systems keep water off the leaves helping reduce those problems.

Keep weeds down around your broccoli. Your plants will appreciate not having to compete with other plants.

Giving your broccoli plants a side dressing of a nitrogen fertilizer, like fish emulsion will help you grow a large main head of broccoli.

As temperatures rise at the end of the growing season broccoli wants to bolt and produce seed. You can help slow this process down by making sure you water consistently, mulch around the plant to keep the soil cool and use some shade cloth to keep the hot sun off the plants.

Common Pests of Broccoli Plants

The biggest insect problems on your broccoli will be aphids and cabbage worms from cabbage loopers.

Aphids are small sucking insects that infest your broccoli plants. Aphids can cause damage to your plants and affect growth, but even worse is that large aphid infestations will cover plants and the apids will get inside the broccoli heads making them unappealing to eat.

The worms from cabbage loopers are small and green. They can cause significant damage to your plants as they munch on the leaves and can also be very unappealing if you find them cooked in your broccoli. Cabbage loopers are those small white butterflies you see flitting around your garden. They lay eggs on all cabbage family plants that then develop into green worms.

Fortunately, there is a simple solution for both aphids and cabbage worms on your broccoli. That solution is simple, use a light fabric row cover. Covering your plants with a light row cover or bug netting will keep aphids away and keep the adult cabbage loopers from landing on your plants and laying eggs. Simply throw some row cover over your plants early in the growing season or consider adding a hoop to your beds that is covered with row cover.

Row covers will also keep off flea beetles, which are another common broccoli pest.

Companion Plants for Broccoli

As I mentioned earlier in this article any quick-growing green (Lettuce, Spinach, Arugula) or radishes will do well under the canopy of a broccoli plant. Below you will see a list of other plants that grow well around broccoli.

• Beets
• Dill
• Cucumbers
• Chamomile
• Potatoes
• Celery

Broccoli doesn’t do well when planted with other members of the brassica family. It also shouldn’t be planted with corn, tomatoes, or strawberries.

Companion planting can also help repel bugs from your garden. Adding some of the following plants can help to keep those bad bugs at bay.

• Dill
• Fennel
• Cilantro
• Yarrow

Nasturtiums are also a good choice as they tend to be a good trap crop for many pests.

When and How To Harvest Your Growing Broccoli

Your broccoli harvest will be ready in about 50 to 60 days after you set your transplants out into the garden. For most gardeners who live in cold winter areas, this will be in June for spring planting, and in October for fall plantings. Those of you who live in warmer areas will be harvesting much earlier in the spring.

Your first indication that a harvest will be on the way soon is the formation of small main heads on the broccoli plants. When you see these small heads start to form it is a good idea to give your broccoli a side-dressing of a good organic fertilizer. This will give the plants a boost that will help them develop large main heads.

Those main heads are a collection of tightly packed flower buds. As the weather warms those broccoli florets will want to “bolt” to seed. So you need to watch your broccoli heads closely during the development process. You want to harvest your broccoli while the flower buds are still tight and before the head yellows. If left too long broccoli heads will bolt and form small yellow flowers. If left this long the quality of your broccoli will diminish fast!

To harvest your broccoli heads simply use a sharp knife to cut the main stalk off about 6 inches below the head. Bring the heads inside and refrigerate immediately.

Fresh-cut broccoli should be immediately refrigerated. Fresh broccoli can last for a week or more in the fridge, but remember that unlike grocery store varieties which are bred to last a long time in storage, most garden varieties won’t hold up much longer than a week. So eat it up quickly.

Broccoli freezes well and can last in the freezer for up to 12 months. Broccoli must be blanched before freezing to retain its quality. If you would like to learn more about freezing broccoli you can check out our tutorial on the topic here.

Our Favorite Variety of Broccoli

We live in garden zone 6b Utah. That means we have very short springs and falls. So the growing window for broccoli is very short.

So we choose broccoli varieties that have fairly short maturity dates. That means we sacrifice larger main heads. But the plants usually make up for that loss with lots of side shoot production.

Our favorite variety of broccoli to plant is a hybrid called Packman. This variety matures in 50 to 60 days which is perfect for our garden.

Growing broccoli can be a little more complicated than some other garden crops, but the harvest is worth the extra effort. Be sure to try some broccoli this year and let me know if you have questions I can help with.