Celery should be planted in early spring or late summer, depending on your climate and whether you’re starting seeds indoors or transplanting seedlings outside.
The best time to plant celery is when daytime temperatures are consistently between 55°F and 70°F, because celery is a cool-season crop that bolts in heat.
If you plant celery too late in spring, the stalks turn tough and bitter before you ever get a decent harvest.
If you plant celery too early while frost is still lurking, the seedlings can yellow, stunt, or die outright.
So when should celery be planted?
You plant celery based on your last frost date, your first fall frost date, and how long your growing season runs.
In this post, we’ll look at exactly when to plant celery, how to time it right in different zones, and a few tricks that make the whole process easier.
Let’s dig in.
When to Plant Celery: The Timing That Actually Works
When you plant celery matters more than almost any other garden crop, because this veggie is picky about temperature from day one.
Here’s how to figure out the right planting window for your garden.
1. Start Seeds Indoors 10 to 12 Weeks Before Your Last Frost
Celery seeds are tiny, slow, and stubborn, so the best time to plant celery seeds is indoors, long before spring arrives.
Count back 10 to 12 weeks from your last expected frost date and sow celery seeds in trays or cells.
They need light to germinate, so press the seeds gently into the soil surface instead of burying them.
Keep the soil consistently moist and the temperature around 70°F, and you’ll see sprouts in two to three weeks.
2. Transplant Seedlings Outside After the Last Frost
You should plant celery seedlings in the garden about two weeks after your last frost date, once nights stay above 50°F.
Harden the seedlings off first by setting them outside for a few hours each day over a week.
Plant them 8 to 10 inches apart in rich, composted soil that holds moisture well.
This is the moment when celery planted at the right time takes off, while celery planted too early just sits there sulking.
3. For a Fall Crop, Plant Celery in Late Summer
If your summers are scorching, the best time to plant celery might be late summer for a fall harvest.
Count back 3 to 4 months from your first fall frost date and start seeds indoors in early summer, or transplant in late summer.
Cool autumn nights bring out the sweetest, crispest celery you’ll ever taste.
Best Time to Plant Celery by Growing Zone
Planting celery at the right time looks different depending on where you live, so let’s break it down by zone.
1. Zones 3 to 5 (Short Seasons)
Start celery seeds indoors in late January or early February, because your growing window is short.
Transplant outside in late May or early June, once the soil has warmed and the frost risk is gone.
2. Zones 6 to 8 (Moderate Seasons)
Sow seeds indoors in February or early March and transplant in April or May.
You can also plant celery in late July or August for a strong fall crop in these zones.
3. Zones 9 to 11 (Long, Hot Seasons)
The best time to plant celery here is fall through winter, since summer heat is brutal on this crop.
Plant celery in September or October and let it grow through the mild months.
Common Mistakes When Planting Celery
Even when you plant celery at the right time, a few slip-ups can ruin the harvest.
1. Planting in Hot Weather
Celery bolts when temperatures climb above 75°F for too long, so avoid planting celery in midsummer heat.
2. Letting the Soil Dry Out
Celery has shallow roots and needs constant moisture, so water deeply and mulch around the plants.
3. Skipping the Hardening Off Stage
Seedlings that go straight from indoors to the garden often shock and stall, so take that week to acclimate them.
So, When Should Celery Be Planted?
Celery should be planted in early spring or late summer, timed around your frost dates and kept away from extreme heat.
Start seeds indoors 10 to 12 weeks before your last frost, transplant two weeks after that frost, and plant a fall crop in late summer for cooler zones.
Get the timing right, and celery planted at the right moment rewards you with crisp, sweet stalks that beat anything from the store.