Beat the Frost: Planting Beets and Beans in August for a Fall Harvest

I almost let August slip by without putting anything new in the ground. Almost. There’s something about the heat and the tomatoes finally doing something interesting that makes you forget the calendar exists. And then you do the math and realize you’ve got a solid 10 to 12 weeks before the first hard frost around here, and suddenly August looks a lot more useful.

Beets and beans are the two crops I keep coming back to for this window. Fast, cheap to seed, and they actually prefer the slightly cooler temps that come with September and October in the Pacific Northwest. Planting them now means you’re harvesting when most of the neighborhood has already pulled everything out and given up. Which, honestly, is one of my favorite feelings.

Why August Works for Beets

Beets want about 55 to 70 days to maturity depending on variety. Plant by mid-August and you’re looking at a harvest window that lands right in October, which is perfect because beet flavor actually improves after a light frost. The cold converts some of the starches to sugar. So the weather is doing you a favor for free, which is basically my favorite kind of gardening.

I’ve had the best luck with Detroit Dark Red from Territorial Seed. A packet runs about $2.89 and I get two or three successions out of it. Chioggia is the candy-striped one my daughters think looks too pretty to eat, so I grow that too. Mostly just to watch them be indecisive about it.

Beet seeds germinate well when soil temps are between 50 and 85 degrees. We’re well inside that range right now. Direct sow them about half an inch deep, thin to 3 inches apart once they’re up, and try not to skip the thinning like I did my first two seasons. Crowded beets give you a lot of greens and very sad little roots. Learn from my poor choices.

Beans Before the Window Closes

You’ve got maybe until August 10th or so for beans, give or take. Bush beans need 50 to 60 days, and they really do not want to be caught by a hard frost at the end. So this one has some actual urgency to it. I’m not being dramatic, that’s just the math.

Bush beans are a better call than pole beans at this point. Pole beans take longer and need the infrastructure, and you don’t want to be stringing up a trellis for a harvest that might not happen. Bush beans, you just scatter them, cover them an inch deep, and they mostly handle themselves. Provider and Contender are both reliable here and I’ve found both at Sky Nursery and occasionally in the seed bins at the McLendon’s in Redmond for around $1.79 a packet.

One thing I got wrong my first time doing this: I watered the bean bed the same way I was watering everything else in August, which is to say, aggressively. Beans don’t love sitting in wet soil waiting to germinate. They rot. I lost most of a planting that way and stood there for a week wondering why nothing was coming up before I figured it out. Water them in when you plant, then back off until you see sprouts.

Prep the Bed Without Spending Much

If your beds have been growing something all summer, give them a little help before you replant. I rake out any old debris, scratch in some compost from the pile out back (free, obviously), and call it done. No full soil amendment at this point in the season. There’s enough fertility left from the spring if you’re not planting the same family in the same spot twice.

Beets and beans don’t need the same soil anyway, which is convenient since they’re going in different beds. Beets want something loose and not too nitrogen-heavy or you get leaves and no roots. Beans fix their own nitrogen, so they basically don’t need anything. It’s the most low-maintenance corner of my garden right now and I appreciate that in late summer when I’m already a little over it.

The Cover Situation

Here in Redmond, the first frost usually shows up sometime in mid to late October. Most years it’s a light one first, which beets shrug off completely. But beans will die at the first sign of frost, so keep an eye on the forecast in October and have a row cover ready. I use a cheapo roll of Agribon-19 I got at the PNW Ag Show for $14.50 a few years ago and it’s still going. Throw it over the beans when the forecast dips below 35 and you’ll buy yourself another week or two easy.

Beets can stay in the ground even after a frost or two. They’re practically smug about it.

Anyway, the point is there’s still time. August feels late but it isn’t, not for these two. Get the seeds in the ground this week and by the time you’re raking leaves you’ll be pulling beets too. I call that a pretty good turnip for the season. (I’m not sorry.)

Photo by Adnan Tokgöz on Unsplash