April 1st is the start of National Celery Month.....but more exciting is that this is another plant that can go into the ground in early spring….here in RI that is always exciting!
When selecting celery seeds, there are two variations that need to be considered when planting. There are “trenching” and “Self blanching”.
Trenching celery requires that soil be mounded up against the stems to produce a crisp, pale stem or that cardboard tubes, used as “collars” be applied to the stems. The non blanching is much easier and just as tasty.
Celery is hardy in zones 2 through 10, and prefer a neutral soil, pH 5.8 to 6.8 ideally). They can grow in any soil, and tolerate full or partly sunny locations. It can be sowed in early spring here in Rhode Island, and in warm areas can be planted mid to late summer for harvest in the late autumn or winter. You can expect to harvest 16 weeks after planting.
Prior to planting, soak seeds for water overnight to help speed up germination. When planting outdoors loosen the soil to a depth of 12 to 15 inches, and mix in 2 to 4 inches of aged manure and or compost. If using fertilizer use a 5-10-10. Keep your soil moist and ensure you have good drainage. It is important that you maintain moist soil and full sun is best for even growth.
If starting indoors, plant 10 to 12 weeks before the last frost date, and for an autumn crop 10 to 12 weeks before first frost date. Be sure to use a high quality seed starting mix. Press the seeds into the soil but do not cover with soil. Try to place the seeds about 1” apart (I know, not easy, they are so tiny!). Cover your trays with plastic wrap and wait! It may take 3 weeks for germination but it will come….
After the seedlings appear, place them under fluorescent lighting 3 inches above the for 16 hours a day. Maintain a temp of 70 to 75 during the day and 60 to 65 at night if possible.
When 2 inches’” tall transplant to peat pots or larger flats where seeds are at least 2” apart. Harden off before transplanting…two weeks before put them outside for a couple of hours at the start, and increasing a hour a day.
Transplant when soil temps are greater than 50 degrees Fahrenheit during the day, and less than 40 degrees to prevent bolting. Water thoroughly. Be sure to provide lots of water, as lack of water will produce small, dry stalks, rather than the 12 to 18inches the plant produces under good conditions. Compost and mulch to keep roots cool while providing nutrients to the plants. You can side dress with a nutrient rich fertilizer, comfrey pellets, or coffee grounds. Be sure to weed carefully so you don’t disturb the roots; celery has very shallow roots.
As stalks grow, tie them tighter to reduce sprawling. If you have a trenching variety, once the stalks are about 1 foot tall, start banking the soil up about 3” at a tie, until you can no hill it.
Celery is at risk of Flea Beetles, slugs and snails, and earwigs. Cover with a garden fabric the first 4 to 6 weeks.
You can start harvesting summer through autumn, until frost stops further growth. In mild regions you can overwinter it. Celery is able to tolerate light frost.
Harvest by cutting the stalks from the outside in, starting when the stalks are about 8” tall.
Store them in a plastic bag in the fridge, where they will keep several weeks.
Some recommended varieties are Utah (which is good for small spaces, only growing to 18” tall), Alfina-60 days to maturity, and Conquistador (which tolerates higher temperatures and drier conditions).