Celery is something many people cook with but not too many gardeners actually grow. It needs a long, cool growing season which can be intimidating if your spring weather quickly turns very hot, like it does here in west central Missouri. But, I've worked a few tricks into my celery growing routine and now can produce beautiful and flavorful celery!
The scientific name for celery is Apium graveolens often referenced as variety dulce to specifically denote types of celery that are grown for the leafy stalks (versus variety rapaceum which refers to celeriac or celery root which is grown for the root that looks kind of like a big turnip).
Celery is in the plant family Apiaceae (previously known as Umbelliferae, or the umbellifors). This is the parsley family, also sometimes called the carrot family. These are all those plants that have those umbrella-like flowers, they look like an umbrella that’s been blown inside out by the wind. The family also includes dill, coriander, cumin, fennel and parsnip. This family also includes a lot of wild cousins that we consider weeds and that can be poisonous to ingest or even touch, like hemlock. They are very attractive to pollinators of all kinds, but specifically bees. (Which is why the family name Umbelliferae was changed to Apiaceae. Apis is latin for bee and that’s the genus name for bees, hence the word apiary for a place where bee hives are kept, and this is why there was a change in designation for this plant family.)
Celery originated in temperate Mediterranean climates in Europe, Asia and Africa. There are still wild celery types that grow in roadside ditches and our cultivated plants may naturalize to a space if they’re allowed to reseed themselves and escape cultivation.
Ethnobotanical Uses
Ethnobotany is the study of a region's plants and their practical uses through the traditional knowledge of a local culture and its people.
These uses are cited as a historical and anthropological resource. NEVER INGEST THE PARTS OF ANY PLANT WITHOUT BEING ABSOLUTELY POSITIVE OF ITS EFFECT UPON THE HUMAN BODY.
That being said, the whole celery plant is edible. Wild celery has both herbal and medicinal properties. The Romans and Egyptians made garlands from celery. The Greeks used it as a culinary herb. The plant is also used in traditional Chinese medicine. It’s been used as a diuretic, to help treat kidney and gall bladder stones, for stomach problems, as an antidote for poisoning, for the treatment of colic in babies, hypertension, bronchitis, asthma, for liver and spleen diseases, and more. Celery has a long history of being used for all different kinds of ailments before being used culinarily.
Speaking of cooking, the celery seed we use culinarily in our kitchen actually comes from wild celery and the wild celery plant itself is actually very bitter. The seeds are used because that bitterness of the whole plant gives the seed a stronger flavor than our cultivated version.
Nutrition
A 100g serving of celery contains just 16 calories, 3g of carbs, just shy of 1g of protein, almost zero fat, and contains potassium, vitamin b6, vitamin c, calcium and a surprising amount of sodium along with magnesium and a little bit of iron. It also has a good amount of fiber. The antioxidants in celery are known to be anti-inflammatory, good for digestion, and for helping to neutralize acids.
Cultivation
Celery is a cool-weather vegetable that dislikes the heat and humidity of our typical West Central Missouri summer, which is why I hesitated to grow it at first. It really prefers air temperatures between 60-75 degrees F, or 15.5 to 24C. It doesn’t love the heat, but it also tends to bolt if the air temperatures are 55 degrees F (12.7C) or below for longer than a week or so. So if your daytime temperatures aren’t getting above this at all for 10 days or more, you’re going to need to cover those plants to raise the temperature up a bit if you can to prevent bolting. Celery isn’t very frost hardy, either. So even if your days are above that 55F you want to protect them at night if it’s going to drop below 32F or 0C. I mean, if carrots are divas, then celery is Goldilocks – not too hot, not too cold, just right.
Which is probably what gives it this reputation for being difficult to grow.
In-ground cultivation
Wild celery, which is what our cultivated celery was bred from, grows in bogs and marshlands. It likes that moist, rich soil, preferably in the full sun. But remember, full sun means 6 to 8 hours, so if you live in a warmer climate and have a space that gets six hours of morning sun but then gets shaded in the hottest part of the afternoon, this may be where you can successfully grow celery plants.
Most celery varieties have maturity dates ranging from 80 to 120 days depending on the variety. If you live in an area with a nice, long, cool growing season you might have some success with those 120-day varieties. I tend to stick with the 80-day ones, due to our sudden heat episodes in the spring.
If you’ll be starting your own seed indoors, start them about 8 to 12 weeks prior to your last spring frost date because these seeds can take as long as three weeks to germinate. If you’re in a very warm climate that can handle growing these through the fall and into winter, then you’re going to want to start them about 10 to 12 weeks before you intend to transplant them outside and get them to maturity before you hit the time of year when your daylight hours dip below 10 hours per day or you begin to get any frosts.
Celery seeds require light to germinate, and this is important to know so we don’t sow the seeds too deep in our trays and that we start them under lights from the get-go. You can either sow about 6 seed per inch, in open flats or use plug trays that have very small cells. Just drop the seeds on the soil surface, press them down, and very, very lightly dust them with a little more potting soil to hold them in place while making sure they get the light they need to germinate. You can also sprinkle a fine layer of vermiculite on top, instead, which will help hold the moisture near the top of the soil around the seeds while still letting the light through.
Place them under lights and keep the soil moist and temperatures around 70–75°F (21-24°C) if possible, then after the seedlings pop up in about 2–3 weeks drop the temperature down to that happy place of 60–75°F (16–21°C). I do not use a seedling heat mat for germination of celery seeds. The lights above them are enough to warm the soil up just enough to help them sprout. A cooler temperature just means it will take slightly longer to germinate, but using a heat mat can overheat them and cause them to not sprout at all. I told you, Goldilocks.
Once your weather is past your last spring frost date and you’re reasonably sure you can cover them if you have any cold snaps, you plant the seedlings out in the garden in a couple of different ways. If you’re planting in rows, put the plants 6–8" apart in rows 24–36" apart. If you’re planting in a block in a bed or using the square-foot method, you’ll want each seedling about 12-15” apart.
If you have a variety that you will need to blanch, we sometimes refer to those as a trenching variety. That’s because you’ll plant them in trenches then you use the soil to mound up around the plant as it grows to keep it sweet and tender. The darker the celery stalks become, the more nutrients they will contain but their texture changes with color; dark green stalks will be tougher and stringier. If you don’t want to mound your celery with soil you can also blanche by cutting the bottoms off of paper bags and dropping them over the plants, leaving the leaves exposed and then tying the bag around the base of the plants with twine. You can also do this with cardboard or milk cartons. That’s a bit of a pain, though, so I just opt for self-blanching varieties that don’t need any extra work.
Container growing
Self-blanching celery can easily be grown in containers with no additional special requirements. Mind your spacing within the container to give the plant room to spread; although celery is fairly upright you don’t want it competing with each other too much. Be sure your container is about 6 to 10 inches deep and space the plants about a foot apart from each other. Then, mulch really, really well so you don’t constantly have to be watering. Celery grows and tastes best when it has lots of moisture and pots and containers tend to dry out much faster than in-ground beds or raised planters, so mulch as best you can around your seedlings if you plant them in containers.
Transplanting
Because celery is so particular about its growing temperatures, this is one plant you want to harden off differently than others when you’re getting ready to transplant them outside. Instead of reducing the temperature they’re in indoors, you’re better off just gradually reducing the amount of water they get on a daily basis over the week or so before you move them outside. This will help them perform better when you move them out and won’t shock them into bolting. Keep your indoor temperatures around the same as what they will be outdoors and reduce the amount of water they get.
No matter where you are growing your celery, in ground or in containers, it likes a soil pH of about 6 to 7, pretty common for most veggies. It does like that consistent moisture throughout the season. Of any garden plant, I would say celery likes having pretty damp soil most of the time, so keep that in mind. If you have an area of your garden that doesn’t drain as well as the rest, you might try celery there. Remember, they were originally wetland plants, so they don’t need the soil to be as well draining as others.
Celery tends to be a bit of a heavy feeder. The roots of celery are pretty shallow so any feeding should either be done at the surface level of the soil or as a foliar spray. I give it a good addition of a balanced amendment at planting time and then a side-dressing or foliar spray about six weeks after planting, and then again a couple weeks later. Preferably feed with something slightly lower in nitrogen, so like a 5-10-10 but if all you have is the balanced all-purpose amendments, like a 10-10-10, that’s fine, too.
Heavy mulching around the plants is not just going to help with moisture retention but also with weeds. Any plant that has shallow roots, like celery, can be susceptible to damage if you have to weed around them too much, so the mulch will help with that.
Pests
Pests of celery include aphids, tarnished plant bug, cabbage loopers, whiteflies, and cutworms. Those first ones can all be kept at bay by using coverings at the time of transplant, so have that insect netting handy. If you’ve seen evidence of cutworms in your garden before, then use collars made from foil or cardboard to keep the away from the young seedlings. I will also say if you have a bed that has lots of potato bugs or what we call rollie pollies, those can infest the roots of celery and eat away at them, and they will also hang out in between the stalks of the plant. If you have an infestation of rollie pollies, be sure you’re removing any dead plant matter and keep the mulch pulled back a little bit from the base of your celery plants. They like those damp dark hiding places.
Diseases
As far as celery diseases, they’re not usually to prevalent in home gardens, more so in commercial operations. Leaf blights, celery mosaic or cucumber mosaic virus are the most common disease, along with black heart, which is caused by a calcium deficiency. I’ve not experienced any of these, but if you have any of the blights or mosaic viruses in your area it’s something to watch and be prepared for.
Harvest
Start to harvest celery as soon as you see those stalks start to fill out and they are about 8 inches tall, usually from early summer and through the fall, up until the first hard frosts stop its growth. Celery is a biennial and so it may overwinter in milder climates, producing occasional stems throughout the coldest months and then picking up again in spring before finally bolting and flowering.
You can harvest plants whole or just take what you need right away and leave the rest. Cutting individual stems as needed keeps them producing over a longer period of time. You can technically harvest them whenever you want; young celery is just as good as older fatter celery stalks and if you’re using them for cooking and not fresh eating, it’s not going to make much of a difference.
Celery can be kept in the garden for up to a month if soil is built up around it to help keep the root zone temperature cooler. Celery will tolerate a light frost, but not too many consecutive frosts. I used frost cloth to keep my celery going all the way through Christmas last year and was harvesting off it the whole time.
Storage
If you harvest the full heads and bring them in to be stored, it is best stored at 32 F or 0C and 90-95% relative humidity. This is basically the crisper drawer in our fridge. Celery should keep for 2 to 3 months this way. So, leave it out in the garden for as long as you can and harvest as needed. Once the temperatures get to be too much for it, either too hot or too cold, harvest the remainder and store them in the fridge for another few months.
I also freeze extra celery. If I’m only going to be using it for soups and stews, celery freezes just fine. I don’t even bother blanching it, just toss it in a bag in the freezer and call it good. I’m sure there’s a proper way to do this, but I don’t bother. The way I do it works for me!
Hopefully this puts you on the path to growing your own flavorful celery right in your own garden.
Your Friend in the Garden,
Additional Resources:
Umbellifer or apiaceae? - Richard Jackson Garden (richardjacksonsgarden.co.uk)
Celery / Apium graveolens Herbal Medicine, Health Benefits, Side Effects (medicalhealthguide.com)
Explore Cornell - Home Gardening - Vegetable Growing Guides - Growing Guide
Celery | College of Agricultural Sciences (oregonstate.edu)