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Broccoli

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Botanical name: Brassica oleracea

Plant type: Vegetable

USDA Hardiness Zones: 3, 4, 5, 6, 7, 8, 9, 10

Sun exposure: Full Sun

Soil type: Sandy

Soil pH: Slightly Acidic to Neutral

Broccoli is a cool-season crop that, like spinach, can be grown in the spring or fall. In fact, you may be able to get a continual harvest throughout both seasons if you time planting correctly. A member of the cabbage family, broccoli is rich in vitamins.

Planting

  • Broccoli is hardy; it can germinate at temps as low as 40ºF.
  • Broccoli requires full sun and moist, fertile soil that's slightly acidic.
  • If you live in a warm climate, a fall planting is best, as broccoli thrives in cool weather. Plant seeds in mid- to late-summer in most places.
  • For spring plantings, direct sow outdoors (or transplant seedlings) 2 to 3 weeks before last spring frost date.
  • For fall plantings, direct sow seeds outdoors 85 to 100 days before your average first fall frost.
  • If you transplant, assume 10 less days for growth or the "days to maturity" on the seed packet.
  • Work in 2 to 4 inches of rich compost or a thin layer of manure before planting.
  • Space plants 12 to 24 inches apart, depending on the side heads you want to harvest.
  • Plant seeds 1 inch deep, 3 inches apart. You will need to thin seedlings.

Care

  • Fertilize three weeks after transplanting.
  • Provide consistent soil moisture with regular watering, especially in drought conditions. Some varieties of broccoli are heat tolerant, but all need moisture.
  • Do not get developing heads wet when watering.
  • Roots are very shallow, do not cultivate. Suffocate weeds with mulch.
  • Mulch will also help to keep soil temperatures down.

Pests

  • Flea Beetles
  • Aphids: Curling leaves may mean that the plant's sap is being sucked by insects. Apply soapy water to all sides of leaves whenever you see aphids.
  • Downy mildew: Yellow patches on leaves are usually caused by moist weather. Keep leaves as dry as possible with good air circulation. Buy resistant varieties.
  • Cabbage loopers: Small holes on the leaves between the veins mean small green caterpillars are present. Look at the undersides of the leaves. Hand pick if the problem is small or control with Bacillus thuringiensis. Use a floating row cover just after planting through harvest to prevent caterpillars.
  • Cabbageworms and other worm pests: Treat same as loopers.
  • Whiteflies
  • Nitrogen deficiency: If the bottom leaves turn yellow and the problem continues toward the top of the plant, the plants need a high nitrogen (but low phosphorus) fertilizer or bloodmeal. Apply at planting, after the main head emerges, and after the main head is harvested. 
  • Clubroot: Quickly wilting plants may be due to this fungus in the soil.  The entire plant, including all roots and root tendrils, must be gently dug up and removed. If the roots are gnarled and misshapen, then clubroot is the problem. Act quickly to remove the plants so that the fungus doesn't continue to live in the soil. Do not compost the plants. Raise the pH of your soil to above 7.2. You may need to sterilize your soil, too.

Harvest/Storage

  • In terms of timing: Harvest broccoli when the buds of the head are firm and tight before the heads flower. If you do see yellow petals, harvest immediately.
  • For best taste, harvest in the morning before the soil heats up.
  • Cut heads from the plant. taking at least 6 inches of stem.
  • Cut the stalk of the main head at a slant, about 5 to 8 inches below the head.
  • Most varieties have side-shoots that will continue to develop after the main head is harvested. You can harvest from one plant for many weeks, in some cases, from spring to fall, if you’re summer isn’t too hot.
  • Store broccoli in the refrigerator for up to 5 days. If you wash before storing, make sure to dry it thoroughly.
  • Broccoli can be blanched and frozen for up to one year.

Recommended Varieties

  • ‘Green Goliath’ is heat-tolerant and sprouts side shoots that will mature for harvesting.
  • ‘Green Duke’ is heat tolerant and an early variety that's especially good for Southern gardeners.
  • ‘Calabrese’ is a prolific Italian heirloom that sprouts side shoots that will mature for harvesting. Great for fall planting, too.
  • 'Flash' is a fast-growing heat-resistant hybrid with good side-shoot production once the central head is cut. Great for fall planting, too.
  • ‘Paragon’ is a popular variety in Canada.

Recipes

Wit & Wisdom

One ounce of broccoli has an equal amount of calcium as one ounce of milk.

Comments

Question does anyone know how

By Rebecca Decker on June 1

Question does anyone know how high and wide I need to put mulch around my Broccoli plants to keep the soil cool so I don't continue to get flowers on my broccoli plants?

A layer of 2 to 4 inches of

By Almanac Staff on June 3

A layer of 2 to 4 inches of mulch will help cool the soil (about 4 to 6 degrees cooler). However, you need to harvest broccoli before the flowers open or show yellow. The mulch will help slow down the heat but the broccoli will keep maturing!

I tried growing broccoli for

By Kathy W. on May 22

I tried growing broccoli for the first time this year. I had some very small growths, then they grew high and got yellow flowers all over. Is it too late to do anything? I was expecting them to grow large heads from the flowers, but I guess I should've found this page before making that assumption.

It sounds like they "bolted".

By Bob Smith on May 26

It sounds like they "bolted". The broccoli heads/florets you eat are the compacted flower buds. Usually you can get the head to form and have time to harvest the main head before they open up (not as tightly clumped) then shoot up and open yellow flowers. But, sometimes if the plant is stressed due to high temp or low water they "bolt" right up to flower. You can cut this portion off (same as harvesting main head) and the plant should begin to form side shoot heads that will be smaller but edible nontheless.

harvest

By Anonymous

Most varieties have side-shoots that will continue to develop after the main head is harvested. You can harvest from one plant for many weeks, in some cases, from spring to fall, if you’re summer isn’t too hot
this is the best part of this plant side shoots you could steam them and add some olive oil on it great as a side dish

1st time grower in texas

By Anonymous

the plants are average nine inches high and beautiful but no buds is this normal? I planted them about a month in a half ago.

My broccoli can get quite

By Almanac Staff

My broccoli can get quite tall before the head starts to form. Even knee-high. It can take 60 to 70 days for some varieties. If you gently push the little leaves away in the centre, can you see florets forming? It may just take some time. If the heads do not form, it's usually due to extreme temperature--usually because it's too hot. This cool-weather veggies does not like heat. Cold shock at seeding can happen, too.

yellow, dying cotyledons

By Anonymous

My broccoli seedlings have one or two true leaves and the cotyledons are turning yellow and dying. Isn't that a bit early for the cotyledons to die? They are about 4 weeks old.

After you get the true leaves

By Almanac Staff

After you get the true leaves (within a week or so), the cotyledons will start to yellow. When they start to yellow, begin fertilizing seedlings by applying a WEAK fertilizer solution each time you water. (Be careful not to "burn" with too much fertilizer.)

Long stems from seed

By Anonymous

I started by plants from seed and 4 weeks later have 3 to 4 inch stems with very small leaves at the very top. These are indoors in peat pots. Can a plant them with a good part of these long stems in the ground?

Reasons for long stems: temps

By Almanac Staff

Reasons for long stems: temps too warm (broccoli likes it 10 degrees cooler than most seedlings), not enough direct sunlight, too much nitrogen in soil. Yes, when you plant, cover the roots and stem with supplemental top soil; dissipate the nitrogen (use fertilizer high in phosphorous and low in nitrogen). Stake the long stem if needed.

Bring them back inside?

By Anonymous

I just transplanted my broccoli plants to their big containers outside. So far, the weather during the day has been in the 50s-60s, with the night temps in the 40s. The forecast calls for high of 48/low of 30 in a couple days. Should I bring the plants back inside, or leave them out? I heard too much variability can make them bolt, but not sure what constitutes "too much." If it helps, I live in right in between zones 7a and 7b. Thanks!

a broccoli chill

By Almanac Staff

Planting zone definitions are guides--good ones, but they are not infallible. Any given spot could be a micro-climate that varies from typical zonal characteristics and expectations. Broccoli is pretty hardy but, yes, it is finicky.
Cold tolerance depends on conditioning. If your plants had been in warmer conditions before transplanting and the temp drops well below freezing, it is very likely you would lose them. If you broccoli plants had experienced relatively cold weather, it is likely that they would survive.
Sometimes it is wise to err on the side of caution. You might do well to bring the containers inside, but into a space/area that mimics recent temp and light conditions. That is, don't bring them into the high heat and lamp light of the house. Perhaps a porch?? Or you could cover the plants.
Either way, return them outside or uncover them during the day.
We hope this helps.

I put mine in 4 months and

By Anonymous

I put mine in 4 months and still nothing. I live in HI so plenty of rain but warmer weather. Should I just pull them??

broccoli

By Almanac Staff

It's not just about the weather. Broccoli needs soil with a pH range of 6–7. It is a heavy feeder, so thrives where the soil is rich in aged manure or rich compost—or both. When planted and while growing it can benefit from a general garden fertilizer, such as 10-30-10, with more nitrogen after harvesting. And, if you are not practicing appropriate crop rotation, it may fail to thrive because of whatever grew in the spot before. For specific assistance, contact your local extension service. We hope this helps.

Broccoli never produced

By Anonymous

Last year my broccoli never produced anything but BIG plants. The stem itself was a big as 2 1/2 to 3 inches thick. I kept thinking okay maybe it is like the asparagus and takes a little longer. A couple did produce a few very tiny florets,but that was it. I let them go to seed as I figured the flowers were pretty.(I eventually pulled all the other ones out so I could plant other veggies)I actually let 1 plant stay over the winter and it is still living! What a waste of my garden space..Any thoughts? I tried both planting from seed and from nursery plants.

Broccoli never produced

By Almanac Staff

It's hard to know exactly what went wrong with your broccoli crop, but consider this:
• Did you amend the soil to the appropriate pH: 6.0-6.5?
• Did you apply potassium and nitrogen before planting and then again to seven weeks after the transplants (or seedings) got established?
• Did you keep the plants well watered and free from stress—such as diseases, weeds, and insects?
• Did you plant too early in spring? The larger that plants are when exposed to a late-season cold period, the higher is the likelihood that they will bolt.
• Did the plants experience a prolonged cold spell, followed by a favorable temps, then high temps? This sounds normal, but the variability may be the cause of bolting.
There is no easy answer. Consider these risks and try again this year. OH, then there's this—if you see broccoli thriving in a garden in your area, tell your tale and ask the gardener what his/her secret is. The best advice is sometimes right next door. Good luck! Let us know how it goes.

I too have gorgeous plants

By Anonymous

I too have gorgeous plants but no broccoli. Be nice if I could eat the leaves!

Yes, you can eat the leaves.

By Alissa on June 16

Yes, you can eat the leaves. Think of it as collard greens or kale. They taste like broccoli too and are super healthy!

Broccoli small

By Anonymous

I had thumb sized heads until I discovered kelp meal. It along with bone meal helped me grow wonderful tender large broccoli that was so good !

You Can

By Anonymous

You can eat the leaves

eating leaves

By Anonymous

In the blooming stage of the plant when the heads are growing It is helpful to free the plant of the leaves and stems that grow near the heads, the more mature ones taste a little bitter but the new growth ones can be as sweet as snap peas.

Cool weather crops

By Anonymous

I live in north central Arkansas and when I saw broccoli, cabbage plants etc. at my local feed store, I bought a few. They are now about 10 inches tall. I have been trying to cover them when frost is forcast but have failed to do so a couple of times and they seem to be fine. Do I need to cover them over winter?

Broccoli can be grown in

By Catherine Boeckmann

Broccoli can be grown in areas with mild winters, not severe winters. This fits central Arkansas-- zone 7b. The timing depends on the variety of broccoli. For a standard type of broccoli, you would normally start harvesting around October but may be able to stretch to January. For the Northern European varieties of broccoli, you can overwinter. Normally, you'd start seeds early summer and transplants by later summer so the broccoli has time to grow large enough to grow by January and survive low temps. The plants will thrive down to 25 degrees F without covering. Some readers say that their broccoli did well down to 10 degrees. Single digits would kill.

cutting your plant and replanting it upside down will it grow

By Anonymous

I was told to cut the top pull the plant and replant it upside down

After winter

By Anonymous

My broccoli did well this summer and now in the fall. When the weather gets colder do I need to pull the plants and replant new in late winter or will my current bud again in the spring. I live in SC if this helps

You can leave your plants in

By Almanac Staff

You can leave your plants in the ground and keep harvesting the side shoots in the winter months. In the spring you need to plant new broccoli plants to get new buds and florets.

When is a good time to plant broccoli in NW TN?

By Anonymous

When is a good time to plant broccoli in NW TN? Im not sure about my dirt either, okra did great, but tomatoes are very small. The dirt is hard packed and rust colored. My garden spot gets about 8 - 12 hours of sun, depending on which end Im on (great big tall wild cherry trees offer shade).

bad soil

By Anonymous

I would add 3 to 5 inches of strait compost u can buy it by the cubic yard from any nursery or the city dump(its cheaper)till it in before spring planting do this every year until the soil will stay loos in summer

Please see our fall planting

By Almanac Staff

Please see our fall planting chart here and look for your frost dates. It lists broccoli and more! http://www.almanac.com/content/succession-gardening-planting-dates-second-crops

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