Can’t Grow Celery? Grow Celeriac

That’s a trick statement, because celeriac is a type of celery. However, all the attempts I’ve ever made to grow regular celery ended poorly. So I was left with buying celery at the store. Since celery is sprayed with 29 varieties of pesticides I bought organic, which wasn’t always available. And when it was, it was puny and pricey. Then I discovered celeriac. Now that I grow celeriac in my garden, I have all the celery I need, year around.

What is celeriac

What we know as celery (Apium graveolens var. graveolens) has thick, flavorful stalks. Celeriac (Apium graveolens var. rapaceum), by contrast, has thin, stringy stalks. It’s grown, instead, for its large, knobby, round root that tastes just like what it is: celery.

Other names for celeriac are knobby celery and celery root. But it’s not really a root. It’s a hypocotyl. Celery-like stems grow upward from the hypocotyl. Hairy roots grow down from the hypocotyl into the soil.

But calling it a root is easier, so let’s do that.

Once peeled, the root is firm and white inside and is just as versatile as celery stalks. Well, almost. Since it’s a firm root and not a juicy U-shape stem, it doesn’t easily lend itself to being filled with peanut butter.

How to start celeriac

Like regular celery, celeriac likes cool weather. It also likes a long season, nearly 4 months. So, to avoid the heat of summer, I start mine indoors some 10 to 12 weeks before the expected last spring frost.

I have tried three different cultivars, two of which didn’t do well in our garden. The one that grows best for us is Diamant.

I start out with little pots half filled with sifted potting soil. The reason I sift the soil is that the seeds are tiny. I’m afraid they might dry out in air pockets created by coarser soil.

The reason I fill the pots only half full is so I can add soil as the sprouts grow. That seems to keep them from growing too leggy and falling over.

Using tweezers, I place 2 tiny celeriac seeds in each pot. In some pots, none will sprout. In some pots, both will. When they’re big enough, I transplant an extra sprout into each empty pot and thin the rest to one per pot.

When all the pots are seeded, I lightly spray them with water. Then I sprinkle a little vermiculite on top and lightly spray again.

Celeriac seeds need to be close to the surface because they require light to germinate. I place the pots under grow lights in a room heated to 70˚F.

From then on I lightly spray the pots daily. Tiny green sprouts appear in about 2 weeks.

How to grow celeriac

Around the time of our last spring frost, I transplant the seedlings. Some years the timing can be a tad tricky. Our Tennessee weather is highly variable, and if we have ten consecutive days of temperatures under 45˚F the plants will bolt.

Celeriac grows well in either full sun or partial shade. Since our summer sun gets pretty hot, I grow celeriac in a part of our garden that gets some shade during the day. In our raised beds I plant them 12 inches apart.

Celeriac is a heavy feeder that grows best in rich well-drained soil. Since we make a lot of compost from chicken and goat manure, our soil is plenty rich.

Celeriac also requires consistent moisture all season. To keep the roots moist, I hill soil around them as they grow. As the summer temperature warms, I mulch them, which also blanches the roots and keeps them tender.

So far I haven’t found celeriac to be especially prone to health problems. The biggest issue I’ve seen, mostly the first year I grew celeriac, as that as summer progresses some of the crowns turn to mush. It seems to be a hot-weather problem called heart rot. So now I watch, and as soon as I discover a root with a soft crown I start sequentially harvesting the largest roots, leaving the smaller ones to continue growing. That has worked for several years, so I must be onto something.

When to Harvest

Celeriac is good down to 20˚F, and supposedly has the best flavor after a frost. But for the above reason I can’t wait that long, and they taste just great to me.

After harvesting roots that grow to about 4 inches across, I wash them, cut off the knobbiest part of the bottom, and remove the stems. The stems are thin and fibrous, but our goats love them. Stored loosely in a plastic bag in the crisper, the roots keep for 6 months or more.

What to do with celeriac

We use celeriac in place of regular celery for making soups, stews, and spaghetti sauce.

One root, peeled and chopped, makes approximately 1½ cups, or about the equivalent of 6 celery stalks. To prevent discoloration when cooking with celeriac, briefly place the pieces in 2 cups of water with 1 T of either vinegar or lemon juice. Leave them in the acidulated water no more than 15 minutes.

Celeriac roots can also be roasted or steamed and mashed, like potatoes. A delicious, and easy, vegetable dish is a French recipe called Mirepoix (pronounced meer-pwa). It’s basically a medley of roasted vegetables. Here is the traditional French version.

Recipe: Mirepoix

Roast for 45 minutes at 425ºF.

When our tomatoes are ripe, I sometimes substitute cherry tomatoes for carrots, and rosemary for thyme. It’s not traditional, but it’s awesome! Either way, this dish alone is reason enough to grow celeriac in your garden.