Question: I’m going to start celery early and then transplant in my garden. What month do you plant celery? I’m trying to figure out how to time it around cool nights. -Paula S.
Answer: The month you should plant celery varies depending on where in the world you are gardening, but we can answer the question of when to plant celery another way. Regions with cool springtimes and summers should plant celery in early spring. If your location has warm spring and summer seasons, you should wait until late summer to plant celery for a late fall or early winter harvest. Celery needs four months of relatively cool weather during its growth period. It does best when daytime temperatures are between 60 and 70 degrees Fahrenheit and the temperature at night doesn’t get cooler than 50 degrees.
For an early spring planting, when eight to 10 weeks remain before your last anticipated frost in the spring, start your celery seeds sprouting indoors. By transplanting time (two to three weeks before the average last frost date in spring), the young celery plants should each have five or six leaves. (If you don’t know your last frost date, you can find out how to determine it by reading our article How to Learn Your Last Frost or Freeze Date.
Will frost kill celery plants?
If the temperature dips near to freezing, it’s likely to cause damage to young celery plants. Once the celery plants have reached maturity (or are close to maturity), their tolerance for cold weather increases and the plants are now able to withstand a short-term frost or freeze. However, there are limits—cold hardy doesn’t mean impervious to cold. Once the thermostat drops below 30 degrees Fahrenheit, even completely mature celery plants will suffer damage or possibly die.
Celery thrives best when the temperature doesn’t drop under about 50 degrees in the coolest part of the night. Either extremely cold weather when the celery plants are young and begin to grow or extremely hot weather when the plants have almost matured can trigger the plants to “bolt” and start forming a seed stalk.