Q&A: I have kale in my garden, but it’s tiny. Can I harvest it now?

This question comes from our client Gretchen in Westmeade. She’s a new gardener, and her smart questions have me regaling you with this ramble. Last week, when the weather was warmer, Gretchen was getting antsy to plant some seeds for spring, but she was worried that there wasn’t enough space in her raised beds. So, should she go ahead and harvest her kale? It doesn’t seem to be doing much all that much sitting there in the dirt..

Per usual, I couldn’t provide a simple yes or no, and I proceeded to get geeky about plant growth in the winter. You see, there are a variety of factors that gardeners tend to think of when measuring a plant’s success or lack thereof. Take a second to list a few…. you with me? Soil quality, sun, pests, weeds, and at this point in the year, temperature, right?! It’s too cold for plants to grow, wouldn’t you think?🥶

But we’re forgetting the most important factor that influences plants right now: day length. We aren’t the only earthlings whose pep is impacted by the short winter days; plants feel it too.

In fact, an OG winter garden guru, Eliot Coleman, (imagine the salt and pepper goodness of Richard Gere. Now add a rake and wheelbarrow😍) created a term for this time of year: “The persephone period.” Named after the Greek goddess Persephone, whose story is closely tied to the cycle of the seasons, the persephone period represents the time of year in which a region gets less than ten hours of sunlight a day.

It varies by geography, but in Nashville it begins on November 25th, when our autumn days shorten to 9 hours and 59 minutes. On December 20th, our shortest day of the year, Nashville only gets 9 hours and 41 minutes of sun. Then, the days lengthen again. Today, we will get 10 hours and 52 minutes. Tomorrow, 10 hours and 54 minutes. Little by little, as the sun dawdles on its daily orb, our plants (and our personalities) perk up a little. By the end of this month, we’ll be up to 11 hours and 23 minutes a day, and those kale leaves are off to the races.

So, should you harvest now? If your plants are especially small, probably not. Give them a week or two to soak up the sun, and they will be much bigger by March. On the other hand, if your plants are large and have a lot of leaves, harvest away! Large overwintered plants were likely placed in the garden well before the persephone period; they were able to grow large while the days were still long, and now they are just chillin, if you will, in the winter weather. (Note: mark your calendars so you remember to plant your fall crops in early September next year! Take that, Persephone!)

My last piece of advice: be aware that as our days get longer and warmer in late April and May, our over-wintered greens grow uncomfortable in the heat, and will become bitter just as we are basking in the spring sunshine. So, don’t put off a harvest for too long! Plan a white bean and collard stew at the end of February and garlicky kale with tahini sauce the first week of March, and get a new spring crop in the ground by April 1.