by Julia Frisbie
posted July 23, 2021
July is the best month to plant root vegetables. Why? Because winter is the best time to EAT them. Beets, rutabagas, turnips, parsnips, and carrots are all sweeter after a frost. If you plant them now, they’ll be nice and big when the weather turns cold. They hold up just fine in the ground over the winter months, allowing you to dig them up and eat them whenever you like.
To understand why, you need to understand how they live their lives. Many root veggies are biennial, making seeds during their second warm season. A would-be carrot mother wants to grow a nice big root during her first summer. This root is her bank account, full of energy stored as starch and sugar that she’s saving for later. When the first touch of frost hits her feathery leaves, she lets them wilt, pulling down every last bit of sugar into her root to serve as antifreeze. (That’s why the root tastes sweeter in winter!) The carrot mother bides her time until spring comes. Then, all at once, she spends down her bank balance in order to build a seed stalk. The sugar she’s stored in her root funds the next generation of carrots.
The carrots who accidentally overwintered in my garden have just flowered, and they look like this:
If July is a good enough time for carrot mothers to fling their progeny into the world, then it’s a good enough time for me. Another indication that it’s time to plant carrots is when their wild cousins, the Queen Anne’s Lace, are blooming in your neighborhood:
These wild relatives are the reason I buy my carrot seed every year rather than saving it from my garden; they’re the same species (Daucus carota) as domestic carrots, and are insect-pollinated, which means they’ll readily cross unless isolated from each other by half a mile. As in many cases, the wild genes for tough, white, hairy, strong-flavored roots are dominant, and will show up in subsequent generations of crossed seed.
As a side note, while I love foraging for wild foods, I leave wild carrots alone. Many plants in the umbelliferae family look alike, and some are extremely poisonous. Hemlock is an example of a toxic umbellifer that grows on Fidalgo island.
The carrots who have come to live among us have given up a lot of their wildness, and with it, their ability to grow in marginal conditions. Domestic carrots are tricky for several reasons:
- First of all, they need deep, loose soil. We have clay. So, I either grow them in my raised beds, or else I choose the old-fashioned (slightly less domesticated) chantenay varieties that can make do with heavy soil.
- Second, they germinate very slowly, and need to be kept moist the whole time. But they can’t be covered too deeply, or they won’t make it. Carrot seeds are tiny. They’re not provisioned for a grueling push of cotyledons through an inch of topsoil the way starchy beans and peas are. They need to be sown just under the surface, and then that surface needs to stay constantly moist until they’re up. But you can’t water them too violently, or they’ll wash away! And you can’t start them in soil blocks or pots where you might have more control over their conditions, because they strongly resent transplanting.
- Third, did I mention that they’re tiny?! It’s hard to get the spacing right when planting them by hand, and if they’re too crowded, then none of them will reach their true potential.
- Fourth, if you do get a good crop of winter carrots, you can bet every other creature would also like to eat them once they’re frost-sweetened. Deer will dig them up. Rodents will tunnel underneath and eat them from below. I built my raised beds behind a six foot privacy fence to thwart the deer, and stapled quarter inch hardware cloth across the bottom of the beds before filling them to thwart the rodents. Of course, the problem with raised beds is, they’re hard to keep moist.
Basically, domestic carrots wouldn’t succeed in the wild unless they were evenly scattered onto a bed of perfectly fine, loose humus, just close enough to the base of a waterfall where they were being constantly misted, and where no animals could find them. It’s almost laughable! But it’s not their fault. This is a direct result of our co-evolutionary dance: the carrots have agreed to be sweet, orange, and tender-crisp in return for our help with germination and growing conditions. Do we remember how to honor our part of the agreement, how to meet our responsibility toward the carrots?
Some years I have better results than others. I console myself during the bad carrot years by supporting our local professionals. Billy at Moondance Farm runs a winter CSA every year that is worth the price for the carrots alone; they’re as sweet as candy. You can also find frost-sweetened carrots at the winter markets. But listen, if we’re serious about food security, we ought to keep trying to grow them ourselves. We’re certainly not going to deepen our relationship with domestic carrots by outsourcing their care.
I’ve tried a lot of tricks to get around the germination difficulties. This is the protocol that’s worked best so far:
- Soak seed in water until white rootlets barely begin to emerge from the first few of them, which takes 4-5 days. This reduces the amount of time you’ll have to keep the bed perfectly moist. Here’s a picture of a germinated carrot seed under a microscope:
- While the seeds are soaking, get irrigation set up. A very fine mist needs to be delivered until the soil is well-saturated AT MINIMUM three times a day. A layer of agribon or shade cloth over the bed can prevent some moisture loss.
- When you see the first signs of germination, mix up a corn starch gel in a ratio of one tablespoon of cornstarch to one cup of water. Whisk it together on the stovetop until it just barely comes to a boil and starts to become translucent, and then stop stirring and let it cool completely.
- While the gel is cooling, water the heck out of the carrot bed, and make tiny trenches where you’ll put the seed.
- Gently mix the wet, barely-germinating seed into the cooled cornstarch gel.
- Put this mixture into some sort of delivery device. I use a squirt bottle, but a plastic bag would work if you snipped off one corner and squeezed it out. In the following photo, you can see seeds suspended in the gel. (You can also see that my gel has a reddish cast, because I added some cinnamon to it as a natural antifungal to try and prevent damping off.)
- Pipe the gel mix into your prepared rows, just like icing onto a cake. Having the seeds suspended in the gel makes it easier to get decent spacing. (You’ll still have to thin the seedlings, but it won’t be as difficult.) Here’s a happy row of seeds suspended in a line of gel:
And here’s a close up of one seed that I took with my pocket microscope after squirting it onto the soil. You can see that it’s at the perfect stage, just barely beginning to germinate. Note the white mycorrhizal threads surrounding it: that’s happy soil!
- Barely cover the row of seed with damp soil, and begin the misting regime.
- Once they have some leaves, thin them to 2-3 inch spacing and reduce your watering to once a day. Keep them well weeded until they’re as tall as your hand.
Even if you do all this, I can’t promise you’ll get perfect carrots. I can only promise you’ll gain a deeper understanding of what a carrot wants (and, potentially, your own insufficiencies in the provision of these desires).
Other winter root vegetables, such as beets, rutabagas, turnips, and parsnips, have never given me this type of trouble. Beets prefer a neutral ph and soil on Fidalgo Island tends to be a bit acidic, so they’re best grown in a raised bed with imported soil, or in a bed prepared with lime. They have big tough seeds that benefit from a warm bath overnight before sowing. Parsnip seed has a short shelf-life and needs to be sourced fresh every year. But I don’t pre-germinate and suspend any other type of seed in a cornstarch gel. I reserve this craziness for carrots alone.
If you consistently grow great carrots without much fuss and bother, please leave a comment and tell me your secrets.
Great column! What’s your favorite sources for fall and winter vegetable seeds? Most seed racks carry them only by accident, not intentionally. I’m in Mt. Vernon, but have been known to travel to Anacortes :~)
Great question! I buy almost all my seed online. Favorite companies include Uprising Organics based out of Bellingham, and Territorial (they publish a whole catalog of fall/winter varieties) based out of Sweet Home, Oregon. I also like Peace Seeds out of Corvallis, Oregon. Nichols Garden Nursery has great herb varieties.