wisconsindead
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Joined: Mon Jun 01, 2015 11:48 pm
Location: Zone 5b

Broccoli and Frost Tolerance

Hey guys,

I am planting my spinach, kale, cabbage and hopefully spinach today. Temps will be in the 30-50 range for the next week but it looks like a cold front is moving in where temps could get as low as 21 degrees F. Can broccoli tolerate this?

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jal_ut
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Joined: Mon Jan 19, 2009 3:20 am
Location: Northern Utah Zone 5

Re: Broccoli and Frost Tolerance

Go for it. The worst that can happen is it freezes and you have to plant again.
Lucky you. Here its 26 degrees and 2 inches of fresh snow on the lot.
Gardening at 5000 feet elevation, zone 4/5 Northern Utah, Frost free from May 25 to September 8 +/-

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applestar
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Location: Zone 6, NJ (3/M)4/E ~ 10/M

Re: Broccoli and Frost Tolerance

These two sites are my go-to for freezing temperature tolerance —

Southern Exposure's Fall & Winter Gardening Guide
https://www.southernexposure.com/southe ... zp-38.html
Broccoli (6/1-7/1): 28 degrees - leaves can handle to 15 degrees, but heads are more tender
Fall & Winter Growing Guides - Winter Planting Chart
https://www.territorialseed.com/product/ ... ing_guides

...note though that there are different types of broccoli varieties, generally indicated as “spring” and “fall” broccoli that have different kinds of cold as well as heat tolerances depending on the variety. Which variety are you growing?

Also, and I looked but didn’t find similar guide as above for broccoli at Johnny’s Selected Seeds, but THEY have excellent germination temperature guides for most vegetable seeds, and if you are sowing these seeds outside in the ground, they may not sprout until temperatures are conducive, and depending on the temperature, it may take up to 3 weeks.

Broccoli can germinate in 3-5 days at optimum temperature indoors, and they grow well at around 50-60°F under lights. Slower at lower temps. They will need to be acclimated to the outside for at least 1 week, but by the time the outside seeds sprout in 3 weeks, you may have nice starts to plant out. Other options are to start them in coldframe, etc. and/or plant them out under low tunnels.

Cabbage can be started the same way. Spinach and Kale are generally more cold tolerant.
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.

gumbo2176
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Location: New Orleans

Re: Broccoli and Frost Tolerance

I plant broccoli in early fall/late summer here in Louisiana, which is early October and we did manage to get 3 nights of low 20 degree weather, which is very unusual for this part of the world. My broccoli did survive and continues making side shoots after the main heads were picked. Now, this wasn't sustained below freezing weather for weeks on end, just a few nights of very cold, for us, temperatures.

wisconsindead
Senior Member
Posts: 168
Joined: Mon Jun 01, 2015 11:48 pm
Location: Zone 5b

Re: Broccoli and Frost Tolerance

Thanks guys, I appreciate the responses and links.

Boboe
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Joined: Sat Mar 25, 2017 6:25 pm
Location: Destin, FL ; Zone 8b

Re: Broccoli and Frost Tolerance

Broccoli and all of the brassicaceae plants are freeze hardy. That means broccoli, radishes, kale, collards, mustard, cabbage, etc.I live in the Florida Panhandle and grow all of these in the winter. We generally have a freeze or two, and those plants don't even wilt a bit, even if not covered.

wisconsindead
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Joined: Mon Jun 01, 2015 11:48 pm
Location: Zone 5b

Re: Broccoli and Frost Tolerance

Figured I should mention that the broccoli, cabbage and kale died during the past few weeks of cold temps. After not much more than a week outside these plants that were a few weeks old and started indoors hit some pretty cold temperatures, into the upper teens. I did add a frost blanket for the coldest nights but they couldn't stand it. I am going to assume it was a combination of transplant shock and low temperatures. I planted more seed in their place, direct seed this time. The spinach is doing fine and beginning to put on some growth.

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