Celery is a staple of the kitchen. It’s a great source of fiber, low in calories, and contains essential nutrients like potassium. Web MD says it has a host of health benefits, too, so it’s a great vegetable to grow in your garden.
There’s even a cutting variety of celery that grows more like an herb, and that can be harvested early and continuously throughout the growing season.
Celery can be a little bit tricky to grow, but most of the difficulty lies in a few key growing features. When you know what those are, you can easily grow all the celery you want from seed.
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- Keys to Easily Growing Great Celery from Seed
- 1. Start seeds early
- 2. Slow germination is typical
- 3. Overplant a little
- 4. Sow on the surface
- 5. Mist to water
- 6. Maintain at optimal warm temperatures while the seed germinates
- 7. Keep above 55 F (12.7 C) once sprouted
- 8. Harden off before transplanting outside
- 9. Plant outside after the danger of frost has passed
- 10. Water regularly
- 11. Harvest before a hard freeze
- A Signal from Nature to Tell You to Plant Celery Outside
- Enjoy Your Homegrown Celery!
Keys to Easily Growing Great Celery from Seed
(*Incidentally, these tips work well for all types of celery and their relatives, like seasoning or cutting celery and celeriac, which may also be called celery root.)
Here are the top tips for successful celery sowing and growing:
1. Start seeds early
Celery is a small seed, and it’s a slow grower. You won’t see it growing in leaps and bounds like lettuce or tomatoes. It takes some time. And it needs time.
Celery especially needs a long time to reach a solid transplant size. Once it’s there, it takes three months or more to grow to harvest size.
Cutting varieties can be harvested earlier because you don’t cut the whole plant to harvest; you just cut stalks off as they grow, as needed. At the end of the season, you can pot the cutting celery to grow indoors or cut the whole plant and dry, freeze, or store the stalks for future use.
You need a minimum of eight weeks to grow celery to transplant size. Twelve weeks is an even better start and you’ll be happier with the transplants’ size if you start 12 weeks, but you can start celery even earlier than that.
Twelve or more weeks will give you bigger, better, stronger transplants.
- For the best results, start celery seeds 12 to 14 weeks before you plan to plant them outside.
2. Slow germination is typical
Don’t be surprised (or worried) if it seems like your celery seeds are taking forever to germinate. The soonest you will seed sprouts is two weeks. Three weeks is common for celery to germinate.
Less-than-optimal conditions can delay celery seed germination. It can also decrease germination rates.
- It can take up to three weeks under optimal conditions for celery seeds to germinate. This is normal!
3. Overplant a little
Germination rates on celery can vary, and they tend to have a lower germination rate than a lot of other types of seed, so it’s smart to overplant a little when you’re starting your celery seeds.
Celery seeds also respond to temperature and conditions, and germination can be lower if the conditions are off or less than ideal.
If you start seeds in a germination pot with a more intensive style of seed starting (like this small-space seed starting method), you can transplant just the best and most successful seedlings when you pot them up a few weeks after germination. You won’t have empty cells from the seeds that didn’t make it.
- Plant more seeds than you think you need to make up for lower germination rates.
4. Sow on the surface
These tiny little seeds can’t fight through too much soil. Don’t sow them too deeply.
The best way to sow celery seeds is to sow them on the surface and then press them into the soil. You don’t need to cover them after pressing them in.
Don't sow celery seeds any deeper than ⅛ of an inch deep.
Celery needs light to germinate, which is why covering them is not good for them. Don’t worry about providing a light-blocking cover—sow celery on the surface and keep it exposed to room light.
If you want to provide a cover to keep them from drying out, use a clear dome or plastic wrap over the germination pot until the seeds come up (then remove it).
It’s best to start celery in seed starting medium rather than potting soil because seedling soil doesn’t have the large chunks that potting soil sometimes does. Large pieces in the soil can smother small celery seeds.
Seeds started in seedling soil should be potted up into nutritious potting soil after they have two sets of true leaves.
- Surface sow celery seeds, then press them into the soil instead of covering them.
5. Mist to water
It’s best to pre-moisten the seed-starting soil before you plant your celery seeds. After, just mist enough to moisten the soil, but don’t overwater.
A mister, spray bottle, or bottom watering is best for celery seeds and seedlings. It’s not a good idea to water them with a watering can because it’s too easy to drown them and dislodge them from the surface. This results in poor germination and seeds clustered where the water left them.
- Mist or bottom water just until the soil is moist. Don’t overwater.
6. Maintain at optimal warm temperatures while the seed germinates
The lowest temperature that celery can take for germinating is 40 degrees Fahrenheit (4.4 Celsius). They may germinate at this temperature, but germination is more likely to be slow and spotty.
The ideal temperature range for germinating celery is between 70 and 75 degrees Fahrenheit (21 to 24 C).
- It’s best to keep celery seeds at a consistent, warm room temperature of around 70 F while seeds germinate.
7. Keep above 55 F (12.7 C) once sprouted
If you’re growing indoors in your house, comfortable room temperature is fine (in the range of 65 to 72 F, around 21C). If there is a reason you want to keep the celery seedlings at a lower ambient temperature, they can take that, too.
Celery can grow well – even as young seedlings – down to a temperature of 55 degrees (F) or 12.7 C. You should keep them at or above this temperature while they are growing to transplant size.
- Keep celery seedlings at or above 55 F/12.7 C while growing.
8. Harden off before transplanting outside
As you get closer to the time you want to plant your celery outside, harden off the plants to acclimate them to outdoor living.
Hardening your transplants will help them withstand the more variable temperature fluctuations of outdoor living, as well as the forces of wind, sun, and rain. Start at least one week, and preferably two, before you plan to plant your celery outdoors.
It also helps to water a little more lightly in the week leading up to the move outdoors, so reduce the water by a bit before planting out (but do not let them dry out completely—the small plants will wilt easily).
This will help them deal with the less consistent moisture that comes from Mother Nature.
- Harden celery transplants before planting them outside.
9. Plant outside after the danger of frost has passed
Though celery is frost-hardy, the young seedlings won’t fare as well as older plants will. Give your seedlings the best start by waiting to plant them outside until after the danger of frost has passed.
The best temperature to plant your celery outside is when the days are above 50 to 55 degrees (10 to 12.7 C). Nighttime temperatures should not fall below 40 F (4.4 C) for any significant amount of time.
If the weather surprises you and you do get a late freak frost after you’ve planted seedlings in the ground, it’s a good idea to cover your celery transplants with a sheet or garden fabric.
- Plant celery transplants outside after your last frost date.
10. Water regularly
If you get consistent weekly rainfall, you will probably get enough rain for your celery to grow well. But celery is made up of 95% water, and so it is a plant that needs good, consistent watering.
If you don’t get at least one to two inches of rainwater per week, irrigate or water celery to make up the difference.
- Make sure your celery plants get one to two inches of water per week.
11. Harvest before a hard freeze
Fall frosts won’t kill your celery, but once hard freezes come, your celery won’t survive so get it out of the ground before a hard freeze comes.
Fortunately, celery will store well for quite a while in a cold refrigerator, and it freezes well and dehydrates well, too. So, plant lots, and save it for all your winter soups, stews, casseroles, and more!
- Harvest your celery before hard freezing temperatures -- below 28 degrees Fahrenheit (-2.2 C).
A Signal from Nature to Tell You to Plant Celery Outside
Here’s a fun tip from the growing experts at Fedco Seeds:
If you want a sign from nature to tell you when it’s a good time to plant your celery transplants into the garden (or container garden if that’s your thing), look to the apple trees.
This is called a “phenological sign” or biological sign. Basically, it means using nature’s blossoming and growing to tell you when conditions are right for planting different things (along with other things phenological signs can tell you).
What’s a good sign from Mother Nature that you can plant your celery outside? Apple blossoms! More specifically, when the apple blossoms have finished and start to fall off the trees.
- Plant celery outdoors when apple blossoms fall.
Enjoy Your Homegrown Celery!
Let’s review the 11 tips for growing great celery from seed (plus a bonus tip):
- For the best results, start celery seeds 12 to 14 weeks before you plan to plant them outside.
- It can take up to three weeks under optimal conditions for celery seeds to germinate. This is normal!
- Plant more seeds than you think you need to make up for lower germination rates.
- Surface sow celery seeds, then press them into the soil instead of covering them. Let them see the light.
- Mist or bottom water just until the soil is moist. Don’t overwater.
- It’s best to keep celery seeds at a consistent, warm room temperature of around 70 F while seeds germinate.
- Keep celery seedlings at or above 55 F/12.7 C while growing.
- Harden celery transplants before planting them outside.
- Plant celery transplants outside after your last frost date.
- Make sure your celery plants get one to two inches of water per week.
- Harvest your celery before hard freezing temperatures -- below 28 degrees Fahrenheit (-2.2 C).
- If you want a natural, biological sign, plant celery outdoors when apple blossoms fall.
That’s all the basics you need to know to grow great celery. Try out some different varieties and mix them up with cutting celery that you can harvest early and all season long, along with celeriac that you can store as a root vegetable.
Celery really isn’t a mystery to grow, but it is one of those vegetables that have its own little quirks, so every growing tip is worth knowing when it comes to growing celery.
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