Can celery survive winter frost?
Written by
Michael Sullivan
Reviewed by
Prof. Martin Thorne, Ph.D.Celery's ability to endure frost in the winter months is surprising for most gardeners who grow this vegetable in an outdoor environment. Mature celery can withstand 28°F (-2°C) as long as some protection is provided, but in my trials in Zone 6b, my plants at this temperature were completely lost at 25°F (-4°C). This has a lot to do with pre-freeze prep. I harden off my plants with cold frames weeks before I receive the first freeze warning.
Frost Protection
- Use double-layer row covers below 32°F (0°C)
- Install hoops to prevent contact with frozen leaves
- Remove covers daily above 40°F (4°C) for airflow
Overwintering in Zones 8+
- Apply 6-inch straw mulch around plant bases
- Wrap trunks with burlap below 28°F (-2°C)
- Prune yellowed outer stalks monthly
Indoor Transition
- Dig plants before first frost with 12-inch root ball
- Use 5-gallon buckets with drainage holes
- Maintain 55-65°F (13-18°C) near south windows
Soil Preparation enhances winter hardiness. During the previous year, I incorporated 3 inches of compost into the beds before the fall rains; the organic matter served to insulate the roots. Do not apply fertilizers with a high nitrogen content after September, as they will induce soft or tender growth that will be instantly killed by frost. Instead, apply potassium once a plant's growth has slowed in the fall to strengthen cell walls.
Signs of Frost Harm
- Transparent, waterlogged leaves
- Blackened stem bases
- Mushy roots upon digging
Salvage Methods
- Cut damaged foliage above growth nodes
- Drench soil with 60°F (16°C) water at dawn
- Apply seaweed extract to reduce shock
Where growing zones are 7 or less, grow celery as an annual and start from seed each spring. My growing-in-containers solution - 10-gallon fabric pots - allows me to bring plants indoors as temperatures drop. Celery plants grown over the winter under LED grow lights produced 60% more stalks than similarly aged celery started from seed in the spring.
Read the full article: How to Grow Celery: Expert Homegrown Guide
