Mature celery plants can survive light frosts with temperature between 28-32 degrees Fahrenheit. Heavy frosts can damage the leaves and stems and cause the plant to die back quickly. Young celery plants can be damaged by light frosts. Plant celery in late summer to give them the growing time over winter to develop strong stems. Pick them before the coldest winter days to avoid frost damage.
Celery Can Survive Light Frost
Celery can survive light frost covering in spring and early winter. Harvesting celery stems before heavy frosts in winter will prevent any damage.
Young plants should always be protected from frost as they can be damaged or even killed. Cover them with small plastic containers or soda bottles if you are expecting a night or early morning frost.
To make sure that celery is mature enough to be harvested before the winter frosts arrive they need to be planted in late summer. This will give them around 6 months to mature and develop.
Celery can be harvested one stem at a time or the whole plant can be removed at once. Avoid planting celery to early in summer as it could cause the plant to go to seed early and not to develop stems.
Temperatures too cold for celery
Temperatures below 28 degrees Fahrenheit is too cold for celery to grow well. When temperatures drop below this level the ground soil will become too cold for celery.
This will slow celery growth and cause the stems to stay small.
How to keep celery growing in cold weather
To keep celery growing well during cold spring weather or the start of winter you can follow a few tips. Here are my easy tips to keep your celery growing well in cold weather.
1. Top dress the soil with compost
Top dressing the soil around celery will help to insulate it and protect the plant roots from cold weather rand light frosts. Add 2 inches of homemade or commercial compost around the root zone of your plants.
Make sure there is a 1 inch gap between the compost and the celery stems to avoid water being trapped and the stems rotting. This covering of compost will help to insulate the soil and protect the celery roots from temperature drops.
2. Cover the soil with straw mulch
Covering the soil around celery with straw mulch is a great way to protect celery plants in cold weather. Add a 3 inch layer of straw mulch around the plants, on top of any compost top dressing.
Keep the straw mulch 1 inch away from the celery stems to prevent rot. The straw mulch will insulate the soil, slowly break down to feed earthworms and soil bacteria and help to protect celery in cold weather.
3. Water deeply but less frequently
Watering celery 1-2 times per week deeply is a great way to help them to grow well over winter. Water the plants in the morning so that they have time to dry out throughout the day.
Watering the celery deeply will encourage the plant to send roots down deeper. This will improve the health of the plant overall and help it to survive cold weather.
4. Avoid adding fertilizer
Avoid adding any fertilizer to your celery in cold weather. Plant growth will naturally slow in the colder weather. Any fertilizer added could burn the roots of the plant.
Remove any competing weeds
To help celery to grow well in winter it is important to remove any competing weeds. Winter rain can bring loads of winter weeds that will spring up and steal nutrients from your celery.
A covering of mulch will help to prevent weeds. Pull any weeds that manage to grow through out by hand to avoid damaging the roots of your celery plant.
Check out this video showing how you can regrow celery from store bought.
Do I need to cover celery when there is a frost?
Young celery plants will need protection from a frost. Even light frosts can kill young plants so it is best to cover them completely with a plastic container. Young celery plants can fit under a soda bottle. Cut off the end and place it over the plant if you are expecting a frost.
Larger celery plants will need protection from heavy frosts. You can cover the whole plant with straw and remove it the next day when the frost has passed.
You can also place a plastic or hessian cover over the plants at night, removing it in the morning to protect the plant from frosts.
Can celery survive a spring frost?
Mature celery plants can survive a light spring frost. Celery that was planted in late summer will be close to harvest size by spring.
Surrounding plants with a 2-3 inch layer of straw mulch in spring is a great way to protect the soil and the plant roots from cold weather.
Can you leave celery in the ground over winter?
Celery plants in late summer should be ready for harvest at the start of winter. Celery can be left in the ground over winter in areas with mild winters and temperatures above 30 degrees Fahrenheit.
Celery can be continually harvested by cutting off the outer stems and leaving the main plant in the ground. This can mean you can continue to harvest celery all winter.
Celery is a cold hardy plant that can survive light frosts. Protect young plants from mild frosts as they are less frost hardy. Plant celery in late summer so they are ready to harvest in early winter before heavy frosts arrive.
For more on growing vegetables in cold weather, check out this article: Can Carrots Survive Frost?