Celery can be a temperamental plant to grow, but once you have the knack of it, you’ll never go back to store-bought celery again. Related to dill, carrots, fennel, and parsley, this biennial has been cultivated in ages past not just for the many ways it can be used in cooking, but for medicinal purposes as well. While celery and celeriac are very similar, they are not the same plant. Celery has a smaller, smoother root and thicker, more substantial stalks.
Celery prefers rich, well-drained soil with consistent moisture. You’ll want to work into the soil about 2 inches of compost over the area in which you’ll plant your celery, and dig it in about 4 inches down. The ideal pH range for this vegetable is 5.8 to 6.7. Celery is a heavy feeder, so add some compost to your planting beds mid-season, and dose with a bit of compost tea or Protogrow® every two to three weeks.
Celery needs calcium, so if your soil is deficient (get it tested!), add some horticultural lime to your garden.
Dig a trench about 12 to 18 inches deep and fill it halfway full with compost and composted manure. Add in about 2 to 3 inches of soil and let everything settle for about a week. You’ll want your trench rows about 24 inches apart.
When to Plant
Celery needs a good five months to grow. If you live in a colder climate, you’ll want to start your seedlings 8 to 10 weeks before last frost in soil that’s about 65 degrees. In warmer areas, set out your transplants in late summer. In zones 9 and 10, plant in November to harvest in the spring. Ideal temperatures are between 58 degrees F and 80 degrees F, and heavy frost will stop plant growth in its tracks.
How to Plant
Since celery is a biennial, you’ll have to trick the seed into thinking it has endured a winter frost and dormant stage. The process for this is called stratifying. To stratify your celery seed, put your seeds in a jar or bag in the refrigerator over the winter, or at least for several weeks. Then, soak your seeds in compost tea for about 6 hours to break their dormant stage.
Sprout your seeds in peat pots or a seed tray. Keep the soil moist and place the pots or tray in a moderately warm place. They should sprout in about three weeks. Transplant seedlings from a seed tray into individual pots when they are about two inches tall. Once the transplants have reached six inches tall, begin hardening them off for about ten days.
After your plants have hardened off, set them out in your trenches. Don’t plant them any deeper than they grew in the pot and water in with compost tea or a fish emulsion fertilizer like Protogrow®. Provide at least one inch of water a week.
As the plant grows, add mulch to cover the root. If temperatures consistently dip below 55 degrees F, cover the plants with row covers.
As the celery matures, it can acquire a bitter taste. Blanching is done to prevent bitterness. While the celery may have a sweeter taste, they’re also paler in color (as the light is blocked out) and the stalks are tenderer.
There are several ways to blanch your celery:
• Mound soil around the stalks when they are 12 inches tall, building the soil up about a third of the way each week until reaching the base of the leaves. Planting in trenches helps to facilitate this method.
• Wrap the stems of the plant in brown paper or newspaper and tie them up with pantyhose.
• Cover the stalks up with large cans (with both ends cut out) or sleeves made from PVC pipe or other material.
Once you’ve begun blanching your celery, be careful about watering. Try to avoid getting the leaves and stalks wet as decreased air circulation because of the blanching cover can cause them to rot.
Cut the plants off at the base, just below the soil line, before frost sets in.
You can store celery (plant and root) in deep boxes with moist sand or moist sphagnum moss around the roots for about four months.
If you find holes in your stalks, slugs may be the problem. Spread diatomaceous earth or crushed eggshells around the plant. Handpick slugs and kill them. Set out slug traps.
Rotted stalks may be from a bacterial or fungal infection. Destroy these plants and use crop rotation. Do not water stalks and leaves—keep your water on the soil and allow for proper air circulation in your planting preparations.
Aphids can be a nuisance, causing misshapen leaves with a sticky coating. Spray your plants with insecticidal soap.
If temperatures go below 50 degrees, your celery may bolt. Use row covers to protect against colder temperatures.
Cracked stems and distorted leaves can be from a boron deficiency. Spray with a liquid seaweed extract every two weeks until symptoms disappear.