How to Grow Your Own Celery

Though growing celery takes a little patience at first (the seeds are very slow to germinate), it is not a difficult plant to grow and the flavor and crispness of home-grown celery makes it well worth setting aside a little corner of ones garden for this delicious and health-enhancing plant.

This post covers:

• How to germinate the seed
• Transplanting/optimal soil conditions
• Watering
• "Cut and come again" - celery beyond the first cutting
• Nutritional content of celery and why to only eat it organically grown 

How to germinate the seed:  Most gardeners have a favorite way of germinating seeds but we'll just share what works for us and you can adapt it to your own preferences. 

Celery seed is very slow to germinate. Seeds can take 2-3 weeks to show their first leaves and the plants are not big enough to be planted in the ground for at least two months after that. Here in the Pacific NW, USA (USDA zone 7b) we start our celery in mid-February and they're usually ready to go into the ground by late April or early May. Don't worry if you've missed that planting schedule; celery can be started all through the spring. 

Celery seed is very slow  to germinate. Celery seedlings (left) over 1 month old. Lettuce (right) approx. 3 weeks old.

Our favorite variety that we grow is called "Utah". It's an heirloom/open-pollinated type so you can save your own seed. One plant will give you enough seed for years of future planting, plenty to use in cooking and to share with other gardeners.

One celery plant starting to flower. One celery plant will yield thousands of seeds!

For starting the seeds, we use tofu-containers with holes drilled in the bottom for drainage (see pic above), on heat mats in our greenhouse. We use a finely-sifted, well-draining potting mix that is not too rich. At this early stage, too much nitrogen can cause an algae-film to grow on the surface of your soil and lead to stem-rot in the plants. Moisten the soil before planting.

Being vegetarian, we eat a lot of tofu! With holes drilled in the bottom for drainage, they make excellent pots for germinating seeds.

Celery seeds are tiny and it can be a challenge not to sow them too thickly. Ideally you want about 1/4" between each seed. Put some seed in the palm of one hand and take a small pinch of seeds in the other hand. If you hold the seeds about 6" above your pot and drop them slowly, they will tend to spread out evenly as they fall. Use only the thinnest covering of finely sifted soil to lightly cover the seeds (or rinsed sand works too - be sure the sand you use doesn't have salts on it if you collected it yourself). Gently press the surface of the soil so the seeds below have good contact.

A good rule of thumb is to only cover seeds with soil twice as deep as the seed is thick. So, a millimeter-sized seed, would be planted approximately 2 mm's deep. 

They will germinate best with some bottom-heat from a heat mat, or to be kept indoors until the seedlings pop up above ground but as soon as the green leaves appear they need sunlight or a grow-lamp. Keep the soil moist (but don't over water!) by bottom-watering (in a shallow dish) or with a plant-mister as too much water can kill the tiny seedlings.

The seedlings will develop an extensive root-system first which can take many weeks. Don't give up on them! 

Transplanting/optimal soil conditions: Our celery seedlings go through two transplanting processes. First, once the root-system has developed and the plants are about 1/4 - 3/8" tall, we carefully tease them apart and give them each their own pot. Jumbo six-packs work fine. We have also used the tofu containers mentioned above (six to a container). These work well if you'll be able to do the next phase of transplanting as soon as the roots fill the soil. The jumbo six-packs extend this time a little bit as they hold more soil.

Transplanting tiny seedlings...

Celery is a heavy-feeder and the soil you transplant into should be well-draining and relatively high in nitrogen and minerals.

Allow the seedlings to grow for about two months or till they have a dense root system and healthy greens. (Celery pictured to the left still needs another month or so to grow. The roots are well-developed but they'll do better with more greens.) Our first transplants go into raised beds in our grow-tunnels (greenhouses) but a few weeks later, a second crop can be planted outside. Celery doesn't mind cool weather but it doesn't want a hard freeze, and, though you want to keep its soil moist, celery doesn't like soggy, wet feet (standing water).

Celery naturally grows flat on the ground (like a starfish - if seen from above). To get upright bunches (like you buy from a market) it must either be grown close together in a block, or in collars. In the first few years we grew celery, we used milk cartons and large soy-milk containers to keep the celery growing upright (see pics). The collars blocked the sun from getting to the celery and hence "blanched" it (kept it from getting too dark-green or tough). But we always had problems with slugs which found the collars to be a perfect habitat. For the last several years we've simply grown the celery close-enough together so each plant holds the others up that are around it. Spacing them about 8" apart seems to be the ideal distance. To use this method (without collars), plant them in a block or square (not a single row). They'll grow fine in a single row, they just won't grow upright and may be darker green and a little more fibrous.

We used to use milk cartons (held in place with bamboo stakes in two corners) to keep celery upright - it tends to flop flat - and to blanch it (direct sun makes celery darker green and more fibrous) but the collars proved to be ideal slug habitat.

Now we plant the celery in "blocks" (not rows), 8" apart, and the plants hold each other upright. They're not quite as blanched as with the collars but it takes less time and we don't have problems with slugs or snails.

Watering: Celery plants are approximately 95% water so they appreciate consistent, deep watering. In the beginning, after they're first transplanted in the ground, they'll need to be watered more frequently but not as deep. Later, it's better to water less frequently but more deeply which encourages the roots to reach down into the soil and pull up the water and minerals from below. Shallow watering creates a shallow root system which is much less tolerant to fluctuations in air-temperature and soil wetness.

Late winter celery in our greenhouse. This has been harvested once and grown again.

"Cut and come again" - celery beyond the first cutting: If you are careful about harvesting, celery will re-sprout from its roots. We cut just above the point at which all the stalks are still joined to the roots. The stalks will not be joined at the root (like you buy it in the store) but this gives the roots the best chance of re-sprouting. Keep the plant watered after harvesting to assist it in putting on new growth. This cut-and-come-again celery in the raised beds of our greenhouses has frequently survived through the winter, providing flavorful, mineral-rich stalks to harvest the following, early spring. Sometimes this second-growth celery is a bit more fibrous but it's still delicious and the fibers won't be a problem if you chop the celery finely.

Second-cutting of celery is often more coarse but also more flavorful. Chop finely to use in soups. "Mmm, good!"

The leaves of celery are typically removed before the bunches are sold in a market but they are delicious, chopped finely in soup or salads. They can also be dehydrated and used for seasoning for when you don't have access to the fresh plants.

Nutritional content of celery: Celery is high in water and fiber-content and very low in calories. Since celery is mostly made of water (almost 95%), it is not particularly high in any one vitamin or mineral. Nevertheless, celery is a good source of vitamin K, with one cup containing about 30% of the recommended daily intake, according to the University of Michigan. Celery can also help you get enough folate, potassium, fiber and the micronutrient molybdenum. It contains small amounts of vitamin C, vitamin A and some B vitamins. "Celery is naturally low in calories, carbohydrates, fat and cholesterol," (Read full post here: Celery: Health benefits & nutrition facts)

Always grow or buy organically grown celery. Having such a high water-content, it absorbs and retains pesticides and herbicides.

If you're not able to grow your own celery, always buy it organically grown. Because of its high-water content, it absorbs lots of whatever herbicides or pesticides that are used in growing it. It consistently shows up in the "Dirty Dozen" of fruits and veggies you should always buy from an organic source. (For more info, read this post: Which Fruits and Vegetables to Always Buy Organic-LINK)

As people tour our gardens, they commonly remark that they've never grown their own celery. We hope this post has helped demystify the process and we wish you much success with your growing.