Ok, it’s truth time. I have never eaten celeriac in my life. In fact, I have no idea what you’re supposed to do with it.
WHEW! Do I ever feel better getting that off my chest!
But here’s the thing, what I have learned so far about which veggies to grow or not grow on your market farm does not have anything to do with whether I like them or not.
Just because I have never tried something doesn’t mean that your customer base hasn’t tried it.
That’s why I will never base my decision to grow or not grow a particular veg on whether I am a fan or not.
This brings us to today’s topic: celeriac.
Maybe not the most popular of root veggies, but still worth it to learn about, in my opinion anyway.
We will be gathering our information from our friend Pam Dawling (Sustainable Market Farming) on how to grow (and cook) the mysterious celeriac.
Varieties of Celeriac
There are really not a whole lot of options here. There are two commonly available varieties:
Diamante, which is 100 DTM (days to maturity), and Large Smooth Prague, which is 110 DTM.
Pam has compared these two varieties and strongly favours Diamante as it is more tolerant of warm weather, less prone to rot, and easier to clean.
Celeriac likes rich soil with lots of organic matter, some shade from midday and afternoon sun, and ample water without waterlogged soil.
Choose beds on the shadier side of your garden.
Celeriac benefits from side-dressing with compost during the growing season or a foliar spray of seaweed
A pH of 5.8-6.7 is ideal.
Mulching is not required as celeriac can rot if it is too damp.
Prevent rot by keeping it weeded and removing some of the lower leaves to improve vital airflow.
Celeriac requires long, steady growth so the task of the grower is to do periodic checks to ensure it is growing.
Celeriac can tolerate frost quite well, so there is no need to hurry to harvest in the fall.
There are a couple of different techniques to soaking celeriac seeds you can try in order to reduce the germination time from three weeks to one.
- Soak the seeds overnight, then freeze for a week before sowing.
- Pour 120°F (48.5°C) water on the seeds and soaking overnight.
Some say that older seed has a better germination rate than new seed because the germination inhibitor that induces dormancy has lost strength.
Pam has found that freshly sown seed comes up just as well as year-old seed in her hoophouse.
You might want to experiment for yourself and see if older seed grows well for you as well.
If the old seed theory is correct, it could have the advantage that seed-borne diseases die before the seed does.
Germination is slow, typically taking 14 to 21 days. Celeriac takes 10-12 weeks to grow to transplant size, so be sure to start in plenty of time.
Pam sows in open flats, then spots out (prick out) into deeper flats.
She sows in early February, about 10 weeks before her last frost date.
Celeriac can be sown from 8-10 weeks before the last frost date to 26-29 weeks before the first fall frost date.
Sow seeds ⅛” deep, and keep the soil surface moist.
The optimal temperature range is 59-70°F (15-21°C). The ideal temperature is 68°F (20°C) during the day and 59°F (15°C) at night.
Emergence takes 7 days at 68°F (20°C). At this temp, 97% of seeds should produce seedlings.
Bring the seedlings into full light in the greenhouse (or windowsill) and grow them at 70-75°F (21-25°C).
When they have two true leaves, the seedlings can be spotted out to individual cells, or a 2” spacing in 3” deep open flats.
Celeriac does not develop deep roots, so deep containers are not needed.
If you have a long growing season, you could direct sow celeriac in the summer, for a late fall harvest.
Celeriac should not be hardened off by reducing temps, as this can cause them to bolt.
More than about 9 nights below 55°F (12°C) will cause bolting.
Plants can have their watering reduced to help them get ready for their move outdoors.
Use rowcover if a cold spell arrives after you have planted them out, or if you know cold weather is likely to return.
Transplant when plants are 2.5-3” tall, and when you have had your last frost and the weather seems settled and warm.
If the weather is cold, just wait.
Pam transplants celeriac around the first week of May, after her last frost around April 30.
Celeriac gets planted 12” apart, with four rows to a 4’ bed. Which’s about 10” between rows.
If they are planted any closer than that in Pam’s humid climate (Virginia), she has found that the poor airflow encourages rot.
Pests and Diseases
The most common pests are aphids, whiteflies, cutworms, tarnished plant bugs, and spider mites.
The most common diseases include fungal diseases Fusarium yellows, Rhizoctonia root and crown rot, and leaf blights.
Caring For Celeriac
The only care that healthy plants need, other than a good regular supply of water, is weeding.
Because roots are shallow, any hoeing of celeriac should be done carefully.
Celeriac can be harvested once it reaches two to four inches in diameter, or larger (grapefruit size).
Pam harvests her celeriac in a single harvest in the fall.
Celeriac is hardy to 20°F (-6.5°C) and gets harvested on Pam’s farm before the storage kohlrabi and turnips.
A light frost can improve the flavour.
To harvest celeriac, loosen the roots with a digging fork, pull the plant out of the ground, and trim off the small root with a sharp knife.
Then, cut off the leaves and collect the roots in buckets or tubs for washing.
After washing and draining, celeriac is stored in perforated plastic bags, tied at the neck.
In a walk-in cooler, they will keep for several months, even until spring.
The keys are temps of 35-40°F (2-5°C) and high humidity.
According to Pam, celeriac has an intriguing sweet nutty taste when cooked.
It can be mixed with other veggies, or for those looking for something different, cut into ½” thick slices, parboiled, then fried in butter or olive oil until lightly browned.
The key is to make sure it is thoroughly cooked and tender.
Some people serve them cooked and mashed with potatoes, or in a potato salad.
They can be julienned, steamed, and served, with perhaps a mixed carrot.
Grated celeriac and beets make a hearty winter salad.
Peeling is more manageable if the roots are first cut into quarters.
Well, there you have it, that’s how to grow and cook celeriac in a nutshell.
While this may not be the most exciting veggie to grow or eat, it sure is unique.
Be prepared to educate your customers on how to properly cook this veg, as I am sure they will ask you how!
While we do not have plans to grow celeriac, I will definitely buy some from another grower at the farmers market this year so I can face my fears and try this weird veggie!
How do you eat celeriac? I am very curious so please let us know in the comments below.
Kathy & Jon
your friendly neighbourhood growers