Swiss Chard Growing Temperature

Swiss chard doesn't take well to the extreme heat of summer here in the low desert, but once the daytime temperatures drop below 100F you can begin seeding your chard outdoors as long as you can give them enough water to survive the heat.

Here in Tucson I've found September to be a great month for this. Beginning early in the month so that sprouts begin to appear around mid-September.

Though I'm in zone 9a, I've recorded temperatures as low as 17F (-8.3C) in the winter garden, and all my Swiss chard survived that fine without frost cloth or extra care.

15F (-9.4C) is often-cited as the low temperature tolerance for chard, beyond which frost cloth and heavy mulching may become necessary.

One of the great things here in the desert is that we hit 71F (21.6C) just 7 hours after hitting the 17F (-8.3C) low temp. Every day the desert warms up immensely, and frost quickly melts away as plants thaw out.

Plants get this chance to warm back up every day during winter in the low desert, and get a great dose of photosynthesis to help power them through the cool nights.

Swiss Chard Temperature Tolerance

Swiss chard will continue growing up to around 95F-100F (35C-38C), however at these high temperatures its growth rate will begin to slow.

Above 100F (38C) sunscald, dehydration, and a weakened immune system will eventually take it. Shade cloth can help take some of the brunt of the sun when temps get hot.

As temperatures cool down, chard will start to thrive. It tolerates some frost down to about 15F to 20F (-9.5C to -7C), but is not very hardy below that or in serious freezes.

Below 15F (-9.5C), damaged cell walls will see chard flop, brown, and eventually die - generally losing their outer leaves first. Frost cloth can be some help in postponing this.

Harvesting Swiss Chard

Always remember to harvest your chard slower than it grows, at least in the beginning. Young leaves are very tender and mild, but taking them can slow down your chard growth if you don't have enough plants to outpace your appetite.

Be sure to plant enough so that you can't eat them as fast as they grow - that's the secret with leafy greens!

I really like planting a "salad" garden which includes chard and kale alongside lettuces and spinach. What I do in the salad garden is plant incredibly dense by broadcasting a mixture of these seeds.

I then constantly "cut and come again" when the leaves are just 1-2" in length. Most leafy greens that would not be so tender when large are exceptionally tender when small.

Catch me out by my salad garden every day in the winter chowin' down like a brontosaurus

Dehydrating Swiss Chard for Storage

A great tip for chard and other leafy greens is that they dehydrate very well. When you have more than you can eat fresh, put them in a dehydrator or even hang them to dry!

The super lower humidity in the Sonoran will dry hanging leaves in just a few days, so don't worry if you don't have a dehydrator.

Dried chard can be ground up or crunched by hand into flakes, which make a great topping or addition to soups, stews, omelettes, smoothies, and baked goods. The possibilities are endless!

I like to dehydrate a number of different types of leafy greens which I store in separate mason jars. You can fit a LOT of dried leaves in a quart mason jar if you crunch them down!

Then I take some of each kind, combine them all together, grind to powder in a coffee grinder, and jar up the mixed green powder as my very own home-grown supergreen superfood powder for smoothies and soups.

This is a great way to make the most of a bumper crop of greens, and add small amounts of greens throughout your diet daily.

If you're struggling with Swiss Chard seedlings that are falling over, check out this article here on solutions.

Do you have any tips for growing Swiss chard? I'd love to hear about what's worked for you and what hasn't in the comment section below.

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