This one is not garden folklore! There a number of cool-tolerant vegetables like carrots, broccoli, and kale that become sweeter tasting after frost sets in. Find out how this happens and which ones you should keep in the ground longer for extra deliciousness.
If you want to venture into more cold weather growing, also see How to Grow Vegetables Outdoors in Winter.
Vegetables That Sweeten With Cooler Temperatures
If you have ever delayed harvesting vegetables in autumn, you probably already know many of them are not only fine to eat but taste even better.
For many veggies, so long as they didn’t freeze, the cool temperatures have improved the sweetness.
I first noticed this with homegrown Brussels sprouts. I had a bunch that were under-sized, so, instead of harvesting them in fall, I left them in the garden.
During a late-winter thaw, I finally picked them and roasted them in the oven (with olive oil and salt—yum!).
That is next level flavor. The sugars caramelize as they roast and it is delicious.
If you are a veggie eater but have never acquired a taste for Brussels sprouts or the other vegetables listed, this is the key. Get post-frost harvests!
How Vegetables Become Sweeter with Frost
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As you can see by the list (above), not all vegetables get better with cold conditions.
First, the vegetable needs to be cool-tolerant (not tender) and the fruit (edible part) needs to be mature when the frosts set in.
Tomatoes and other warmth-lovers are sensitive to frost and will freeze and die rather than adapt. But you can ripen some green tomatoes after picking.
But the cool weather veggies are going to improve with the cold.
How It Works
The sweetness of vegetables comes from their sugar content.
Plants create sugars through photosynthesis:
Carbon dioxide is taken from the air, water from the soil, and, powered by sunlight, create sugars.
That sugar is often stored as starch, which is essentially a long chain of glucose.
Even though starch doesn’t taste sweet, that’s really what it is, a big chain of sugar.
When plants experience frost or cold temperatures, that’s a threat.
Ice can form within the plant, in its cells, leading to dehydration and other dangers.
So, plants have developed various responses as part of their acclimation or cold hardening processes, and one of those is to free up some of those sugars stored as starch.
Sugar helps defend against frost damage: these plants will accumulate sugar in response to cold stress.
And, unlike starch, the sugar does taste sweet.
Does growing in cold weather guarantee sweetness?
No. Whether you notice the difference will depend on the vegetable’s traits, your taste buds, and how much sugar has accumulated.
But the odds are, you will enjoy a boost in sweetness.
Growing Vegetables in Fall and Winter
I was first introduced to cold-weather vegetable gardening when I read Niki Jabbour’s book, The Year-Round Vegetable Gardener.
The goal is to keep your fall and winter veggies protected with covers or cold frames so they can chill without freezing.
If you are new to the idea, it’s a great resource for getting started.
Here are more articles on my own winter veggie experiments:
- How To Grow Vegetables In The Winter | Yes, you can grow year-round in a cold climate.
- Veggies & Herbs to Grow in the Fall | Free Printable | What to sow in autumn.
- 20 Quick-Growing Veggies | Fall & Spring | Cool weather veggies to grow.
- The Leaf Tip that Can Transform Your Garden | Smart tip!
- 7 DIY Growing Season Extenders | Cold Frames+ | Tips to keep your veggies snug.
- Easy Winter Composting in a Cold Climate | Composting is a year-round sport.
~Melissa the Empress of Dirt ♛