Did you know that some vegetables thrive in cool weather and really won’t do well in the summer heat? Cool season vegetables love to grow in the cool of spring and fall.
Understanding the difference between Cool Season Vegetables and Warm Season Vegetables is very important. This is something that many new gardeners don’t understand, and it leads to some frustrations and problems.
Growing Conditions For Cold Hardy Vegetables
Cool season veggies prefer to grow in temperatures that are at least 15 degrees below those preferred by warm season crops. Most cool season vegetables do best when the temperatures are in the 70s (20 to 26° Celsius). Warmer temperatures, those above 80 degrees (26° Celsius) will start to affect the quality of the plant. Warm temperatures are a signal for cool season vegetables to bolt (start producing seeds). This will cause most cool season vegetables to become bitter and have a tougher texture.
Most cool season veggies are grown for their leaves (lettuces), immature flowers (broccoli), roots (carrots) or in one case seeds (peas). The cool temperatures enhance the flavor and texture of these plants.
Best time of year to Plant Cold Weather Vegetables
The advantage to cool season vegetables is they can be planted twice! There are two growing seasons for cool season crops, spring and fall. Warm season vegetables like tomatoes, peppers, and cucumbers can only be planted one time in your gardening season.
It is so nice to be able to enjoy cold weather vegetables twice a year. They should be planted in the cool spring season but in early spring before it gets too hot. In early spring you can even warm up the soil to help your seeds germinate better. Learn how to do that in this article here.
The next season to start your cold season vegetables is in the fall. In order for you to get a nice fall harvest, most seeds need to be started in late summer in your garden. You may need to start your own seedlings inside in early summer so they are ready to be planted later in the summer.
When do you plant cool season vegetables?
Your cold hardy vegetables need to be planted early enough so they have enough time to mature and can be harvested before the heat of summer causes them to bolt and go to seed. You can start most cool season crops 4 to 6 weeks before your last frost date in the spring.
Cold weather vegetables can also be planted again in late summer for a nice fall harvest or for more cold hardy vegetables you can harvest through the winter. Look at your seed package to see the days to maturity. They need to be planted early so that the plant is mature enough to either be harvested through the winter or can be harvested in the late fall before winter sets in. This usually is 6 to 8 weeks before your first frost in the fall.
Many cold hardy vegetables can even grow during the winter months if you offer them protection from a hoop house or cold frame. Yes, you read that right you can harvest vegetables all winter. You really can have something fresh from your garden all year!! You can learn more about winter vegetable gardening from this series I wrote on the topic.
Frost is Okay for Cool Season Vegetables
Cool season crops can also withstand brief periods of frost at night and most will continue to do well when temperatures at night drop into the 30s (0° to 5° Celsius). In fact, a light frost will actually improve the flavor of many cool season vegetables like broccoli, spinach, kale, and even carrots.
If your weather forecast predicts some extended periods of frost you might consider protecting your crops from that frost. Fabric row covers placed on your plants in the evening and removed during the day will do a great job at keeping frost damage at bay.
Complete List of Cool Season Vegetables
Root Crops
- Carrots
- Beets
- Radishes
- Turnips
- Parsnips
- Garlic (Plant in the Fall)
- Leeks
- Onions
- Bunching Onions
- Shallots
- Salsify
- Potatoes
- Rutabaga
Leafy Greens
- Lettuce
- Spinach
- Arugula (Rocket)
- Claytonia
- Mache
- Mizuna
- Swiss Chard
- Mustard Greens
- Asian Greens
- Pak choi (Bok choy)
- Tot Soy
- Endive
- Radicchio
Cabbage Family Crops
- Broccoli
- Cabbage
- Cauliflower
- Kohlrabi
- Kale
- Collards
- Brussels Sprouts
- Sprouting Broccoli
Other Crops
- Artichoke
- Asparagus
- Cress
- Peas
- Rhubarb
- Celery and Celeriac
Herbs
- Fennel
- Cilantro
- Parsley
What is a cool season vegetable?
Cool season vegetables are crops that grow better in the cool times of the year. Most prefer to grow in temperatures under 75 degrees. Examples include lettuce, onions, carrots, broccoli, and cabbage.
What are some cool weather crops?
Examples of cool weather crops include leafy greens (lettuce, spinach, Swiss chard), root crops (carrots, radishes, turnips), and cabbage family crops (broccoli, cabbage, cauliflower).
Is 40 degrees too cold for vegetable plants?
Night time temperatures of 40 degrees will be fine for most cool season crops, but if your daytime temperatures are around 40 degrees then you will find it hard to grow even cool season crops because nighttime temperatures will be well below freezing.
What temperature is too cold for vegetables?
The hardiest of the cool season vegetables will hold up to temperatures at or slightly below freezing (32° F, 0° C). But if your temperatures are going to be much colder than freezing for several nights in a row you should protect your vegetables with fabric row covers or a cold frame.
Which plants grow in cold climates?
Cool season vegetables like lettuce, broccoli, carrots and many more will grow well in the late spring and summer in cold climates.
Gardening isn’t just for the summertime! These cool season crops will grow well in cooler temperatures and extend your harvest into the spring and fall! Which of these crops will you be trying out this year?
How to Know When to Pick Your Peaches
I am in the Atlanta Area.
Can you suggest a good seed company?
There are 3 online companies that I buy from and have been very happy with. MIGardener, Jonny Seeds, and Territorial Seed.
Baker Creek otherwise known as rare seeds is the best seed source I’ve ever found. Be a little careful if you buy from territorial seeds, they have a lot of F1 hybrid seed varieties. I steer clear away from those. You can’t go wrong with Baker Creek
Nothing wrong with F1 hybrids as long are you aren’t worried about saving seeds. They sometimes offer a lot of great benefits. I’m a strong believer in using both hybrids and open-pollinated seeds in my garden.
A couple of questions. Your article says that cool season vegetables are those that prefer temps around 70 and can be planted 4 to 6 weeks before the last frost. A bit later down it says they prefer temps under 75, but still in the same ballpark. I live in Connecticut, zone 5B.
The last Frost is around May 21st although last year we had frost on June 3rd. If I back up 6 weeks, that’ll bring me to April 9th. The outdoor temps in the day are usually around 50-60 and at nights definitely in the 30s sometimes colder. Most years we continue to receive snow after April 9th. I know large healthy cool season crops such as mature dinosaur kale could survive a little bit of snow but for young seedlings / small plants, the weight of the snow itself can often crush the plants – especially if it’s a significant storm. I’ve had it happen many times.
The bigger problem I have found is the night temps. Cool season crops are, as you said, mostly frost tolerant. However, in April it is not at all uncommon to have temperatures in the teens which is a hard frost not just a freeze and it’s not possible to cover everything at night and uncover it in the morning. Cold frames work wonderful if you have a small garden but are quite expensive and not effective if you have a bigger piece of land that you are growing on. What is your solution for this? I’ve tinkered with row tunnels, usually using fabric and steel hoops, and many times I’ve come out after a snowfall to find the hoops crushed by the weight of the snow and the plants broken beneath them. Outside of that, that too can get expensive if you’re covering a variety of crops in a variety of areas. Many plants don’t like to be grown together so for that reason it’s not possible to clump them all under one protected area. Some areas of the country don’t have such extremes in temperature changes, but areas like mine do and it makes growing cool season crops difficult. The day might hit 60, but the night might only be 15. Or it may be 50 it is so unpredictable. Comments?
Sounds like you need to get serious about some hoop houses or cold frames, that will solve many of the issues you are worried about.
Good afternoon,
I am new to being serious about gardening and live in NC. My plants, thus far, are doing great and nothing serious as been chewing on them. My question is when should I start thinking about my cool weather garden? I don’t want to miss out or time it poorly. I’d like to have sweet potatoes, red potatoes, carrots, radishes, onions, cabbage and garlic. Are these beginner friendly? 🙂 I apologize for the newbie questions.
Hi Amy! I’m always happy to help. Based on what I know about NC you are almost out of your cool season. Normally you start planting cool season crops 4-6 weeks before your last frost. Right now you could still probably plant lettuce and other greens and they would be fine.
Sweet potatoes ARE NOT a cool-season crop. They are frost sensitive and you have to wait until after your last frost to plant those. Red potatoes and carrots would still be okay to plant as they are warmer than cool season. Garlic is planted in the fall so don’t worry about it this year, plant some this coming fall for a harvest next summer. I also feel like you might be a little late for onions, I planted mine a month ago and I’m in a colder zone than you.
My suggestion for you is to start focusing on warm-season crops right now. Tomatoes, Potatoes, Sweet Potatoes, Squash, cucumbers, zucchini, beans, and corn. Then worry about your cool-season crops again when the fall gets closer.
As a new gardener, I think you would love The Gardening Academy. Check it out here http://www.thegardeningacademy.com
Thank you for the info!! I will work on what I have now and get through the hot months. It’s already in the 80’s here so the humidity is coming! 🙂