You may or may not be familiar with celeriac (or celery root). This root vegetable is commonly found in European cuisine and is part of the same species as celery, just a different variety.
At the New England Vegetable & Fruit Conference, Peyton Ginakes, a UMaine Cooperative Extension research associate, spoke about her research with different celeriac varieties.
Ginakes has been conducting celeriac variety research trials for a few years, growing them alongside celery. As growing this crop is something Ginakes started working on pretty recently, it’s still “a mysterious crop” to work with.
Although similar to celery, celeriac plants are more picky, are “slightly tougher than celery” and are “pretty hardy.” In terms of nutrient and irrigation requirements, celeriac is a “very full-season and relatively demanding plant” but not competitive.
Celeriac takes a very long time to grow, according to Ginakes, and the flavor improves while growing during frost periods. The harvesting process is “fairly intensive,” as it has to be dug out of the ground, as their hardy root system is “almost impossible to pull out.”
People often aren’t sure what to do with the crop, but celeriac can be eaten raw or cooked/roasted. The primarily-edible portion of the crop is its roots, and it’s common to eat it mashed or even added into soups.
Ginakes conducted two parts of this celeriac experiment throughout 2023 and 2024: a variety trial and a planting density trial. The variety trial included six options (‘Alicia,’ ‘Balena,’ ‘Brilliant,’ ‘Diamant,’ ‘Mars’ and ‘Rowena’), all planted in beds on white plastic. At the time of harvest, Ginakes recorded the size of each celeriac and weighed them after trimming.
The results were “pretty variable” throughout the two years, with sizes ranging from 100 to 200 lbs. per 100-foot bed. ‘Alicia’ and ‘Rowena’ consistently produced a large yield of celeriac throughout both years. Ginakes found that ‘Alicia’ was “one of the nicest varieties we worked with.” It was a fairly large variety and “needed the least trimming.”
‘Diamant’ was her “second preferred cultivar in terms of overall visual quality.” ‘Rowena’ was high-yielding in terms of size but required “a fair amount of side trimming.” ‘Mars’ had the lowest yields.
The plant spacing trial looked to find what spacing resulted in the largest quantity of celeriac that are also adequately sized. They tested three different varieties but found no significant difference in the results. The crops were planted in six different densities: two rows and three rows of six inches, 12 inches and 18 inches.
The results were “very intuitive,” supporting that planting at a high-density results in more plants of a smaller size. The 2023 results were slightly lower due to excessive moisture. The two-row spacings tended to do better than their three-row counterparts, and the two rows at six inches resulted in the highest marketable yield.
When determining what planting density to do on your farm, you should take into consideration the amount of space you have to work with, the crop size you desire and the quantity needed for market. Ginakes recommended growing celeriac on the bare ground, or on white plastic, as it provides better plant vigor.
Based on the two experiments, “‘Rowena,’ ‘Diamant’ and ‘Alicia’ were all very nice varieties both for their size and visual quality,” Ginakes reported, and the crop should not be planted any more densely than six inches apart.
Ginakes plans to continue researching this intensive and fairly unknown crop, including conducting a storage trial to see if the internal quality of the celeriac decreases overtime in storage.
