Frost Tolerance of Garden Vegetables #1

I like to engage in risky behavior:

  • I’ve climbed the second tallest mountain in Washington State
  • I like to scramble around precarious places – rocks, trees, etc.
  • Sometimes I get paid to light large swaths of acreage on fire
  • I like to set my plants out earlier in the year than recommended.
Frosted Tips

Frosted Tips

This poor baby Sweet 100 Cherry Tomato
has been damaged. I left for a few days and decided it would be better to leave them outside in the natural light than leave them under my lamps.

Now, I knew it was supposed to get down to 32 F or so but I risked it anyway. I knew it would be better for the plants to be in open air and natural light for the four days I was gone, rather than be inside under fluorescent lights.

The dark edges on the leaves are necrotic (dead) from the cold, whereas the lighter spots are sun damage. After being inside under the weak fluorescent lights for so long, the real thing can be a bit much for plants to handle. I didn’t want the poor plant babies to get sunburned again this year so I risked a bit of frost nip.

Through my trials and experiments (read: lazyness and carelessness), I’ve found that baby plants can handle a lot more than you think. Once, I planted everything in early May and left for a week, only to have a 28 F Freeze, A FULL ON FREEZE! I was devastated! I though all the baby plants would die. Everything but that Basil lived. The eggplant lived, the peppers lived, the squash lived, the cucumbers lived, even the tomatoes lived along with all of the other more hardy vegetables. Out of those, only the peppers didn’t actually produce any fruit.

Warning: The hardiness of plants depends on the variety, . Furthermore, one frost is waayyyy different than multiple days of freezing temperatures. Wind speed and daytime highs also play a role in how well plants will handle frost. These are my non-scientific findings and may not apply everywhere. To follow my advice may result in some damage to plants, reduced yields, or even dead plants. Remember, hardening off is important. 

There is a lot of good information out there about frost tolerance and this is one below of my favorite infographics on the subject. But it’s WRONG!

Getting started, find your Frost Free Date. Your USDA Plant Zone can also be useful. I also recommend checking a 10-Day Forecast in the weeks leading up to your normal Frost Free Date because it could be later or earlier, depending on the year.

Very Hardy

All of these can be planted as soon as the soil is thawed. The plants won’t germinate until after the soil warms (40 degrees F for some varieties, closer to 50 degrees is optimum for others).

First of all, Asparagus is a perennial so it doesn’t need to be planted every year. It takes careful planning to start but is certainly worth it. Rodales has a great How to Grow Asparagus explanation. If you start using crowns (pieces of the roots), 4 to 6 weeks before the LFD (Last Frost Date) is pretty accurate. If you’re starting from seed, you need to start inside earlier, in February or March (especially in cooler climates) and probably wait a whole year before planting out.

Rhubarb is also a perennial. This year, I planted some in mid-March (8 weeks before my frost date) and it’s doing just fine.

Fava Beans and Arugula also fall under this category.
Frost Tolerant

You can probably plant all of these a bit earlier, especially if you start them from seed. They won’t come up until it’s warm enough and won’t be damaged. I’d be a bit more cautions of you are transplanting but I bet four weeks to six weeks before the frost free date would be fine. I’m a risk taker! If you invest in some Frost Cloth, row covers, or even an old sheet you could plant these a bit earlier or a least have a piece of mind.
Tender

Tomatoes can handle down to 28 F but will get damaged! Even at 32 F they get damaged, but they will live and produce.

I would plant snap peas much earlier, like four weeks earlier, I don’t know what they were thinking.
Warm Loving
Infographic Source: Fix.com

This one is pretty accurate. Peppers are babies. They’re sensitive little buggers that need to be sheltered in the beginning. Squash, Melons and Cucumbers need the soil to reach 60 degrees before they will germinate.

I highly recommend taking some risks, getting a few frosted tips and taking notes about what works for you.

Next, I’ll go into some more detail about frost tolerance, soil temperature and planting dates. 

Remember, Frosted Tips were cool once.

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