Last Updated on September 17, 2026
How Many Celery Plants per Square Foot?
4 celery plants per square foot, 6 inches apart, is the number on my square foot gardening chart. The Plan My Garden planner uses a different number, 2 plants per square, set on the diagonal, also about 6 inches apart, sized for a full head with real stalk width. Neither matches how extension programs actually space celery in a row, which is much wider than a square foot grid. Use the chart’s 4 for more, thinner stalks, or the planner’s 2, or fewer, for real girth, if you can keep up with the steady moisture this 120 day crop needs.
The spacing pattern
| Per square foot | 4 plants, on a 2 by 2 grid |
|---|---|
| Inches apart | 6 inches, plant to plant |
| 4 x 4 bed (16 squares) | up to 64 celery plants |
| 4 x 8 bed (32 squares) | up to 128 celery plants |
| 3 x 6 bed (18 squares) | up to 72 celery plants |
That 4 per square is straight off my square foot gardening chart; check other bed sizes with the square foot garden calculator. These are grid maximums for the chart’s tight spacing, not a planting target. For the planner’s fuller spacing, 2 per square on the diagonal, cut the counts roughly in half: up to 32 in a 4 x 4 bed, 64 in a 4 x 8, 36 in a 3 x 6.
Why sources say 2 or 4 celery plants per square foot
| Source | Spacing | Per square foot |
|---|---|---|
| My square foot gardening chart | 6 inches apart on a grid | 4 |
| Plan My Garden planner | 2 per square, about 6 inches apart, diagonal | 2 |
| Utah State University Extension | rows 2 feet apart, plants 12 inches apart in the row | about 0.5 (12 in x 24 in = 2 sq ft per plant) |
| Oregon State University Extension (commercial) | rows 15 to 20 inches apart, plants 6 to 8 inches apart in the row | about 1 (7 in x 17.5 in is close to 1 sq ft) |
University rows leave far more room per plant, about 2 square feet in a home garden row and close to 1 square foot even in tighter commercial rows. A raised bed square can’t offer that much, so the chart’s 4 and the planner’s 2 are both already a compromise. Utah State University Extension calls its own 12 inch spacing tight, forcing tall growth and long petioles instead of girth, the same tradeoff at any square foot spacing. Pick the chart’s 4 for more, thinner stalks, or the planner’s 2, or fewer, for real girth, if you can give celery the steady moisture it needs.
Planting the square
- Start seed indoors 10 to 8 weeks before your last frost, the planner’s window. Sow it on the surface or barely cover it, my Seed Germination Temperature Chart notes celery needs diffuse light to germinate. Soak the seed first and change the water daily, Utah State University Extension’s tip for leaching out natural germination inhibitors.
- Transplant out 1 to 3 weeks after your last frost, later than most spring crops. Utah State University Extension’s FAQ says cool weather for several weeks can make young celery bolt instead of heading up.
- Set 4 plants per square in a grid, 6 inches apart, for the chart spacing, or 2 on the diagonal, about 6 inches apart, for the planner’s fuller head.
- Mulch with black plastic or compost, useful since celery’s roots stay shallow, and water consistently, 1 to 2 inches a week. Uneven watering is the main cause of tough, stringy, bitter stalks, Utah State and Oregon State University Extension both note.
When to plant celery
These are the windows the Plan My Garden planner uses, counted from your average last spring frost. Turn the weeks into dates with the seed starting calendar, or enter your zip code on Plan My Garden to find your frost dates.
| Start indoors | 10 weeks before to 8 weeks before your last frost |
|---|---|
| Transplant out | 1 to 3 weeks after your last frost, not before |
| Direct sow | No separate week in the planner. Oregon State University Extension’s commercial guide says direct seeding isn’t recommended, a uniform stand is hard to get and it takes too long to mature that way |
| Days to maturity | about 120 days, one of the longest on my vegetable days to maturity chart. Oregon State University Extension lists 110 to 150 days from transplant |
| Frost tolerance | Semi-hardy on my vegetable frost tolerance chart. A mature plant takes some cold, but a young one exposed to cool weather for weeks can bolt instead, Utah State University Extension’s FAQ warns |
Soil temperature for germination
From my Seed Germination Temperature Chart: celery germinates from a minimum of 40°F. It gives celery no numeric optimum, noting instead that the seed needs diffuse light and a night temperature 10 to 15°F cooler than the day, around 85°F by day and 70°F at night. Its germination-days data, run at a constant soil temperature, shows celery is slow, and runs backward from most vegetables at the warm end:
| Soil temperature | Days to emerge |
|---|---|
| 41°F | 41 days |
| 50°F | 16 days |
| 59°F | 12 days |
| 68°F | 7 days |
| 77°F and up | none recorded on the chart |
Celery seed is fastest around 68°F, then my chart shows no germination at all at 77°F or above, right where most vegetable seed speeds up.
Growing notes
Celery needs steady moisture for its whole 120 day season, 1 to 2 inches a week soaked in fully since its roots stay small and shallow, Utah State University Extension says. Water stress turns stalks stringy with a strong flavor, and hot, dry weather at harvest can make them tough and bitter, the same extension notes. Oregon State University Extension adds a cause that has nothing to do with water: stalks left too long develop pith inside the petioles, so harvest before that happens.
Pick outer stalks or take the whole plant. Utah State University Extension says to remove outer petioles once they’re a foot or more long, which lets the plant keep producing, or wait until the whole head is 3 inches or more in diameter and harvest it all at once; it suggests 5 to 10 plants per person for fresh eating and storage. Celery shares its plant family with parsley and dill; see how many parsley plants per square foot.
Where to get seed
Wood Prairie’s organic celery seed includes Ventura, a Utah Tall type at 80 to 100 days, the same Utah type Utah State University Extension recommends. It also lists cutting celery, an 85 day herb type grown for leaf flavor rather than full stalks. Code PMG5 takes 5 percent off.
Quick questions
How many celery plants fit in a 4×8 raised bed?
Up to 128 at the chart’s 4 per square, 6 inches apart. The Plan My Garden planner uses 2 per square instead, on the diagonal, fitting up to 64 for a fuller head.
What is celery spacing in square foot gardening?
My square foot gardening chart puts celery at 4 per square, 6 inches apart. The Plan My Garden planner instead uses 2 per square, about 6 inches apart on the diagonal. Both are tighter than university row spacing, which runs closer to 0.5 to 1 plant per square foot.
Why do celery stalks turn stringy or bitter?
Mainly water stress. Utah State University Extension says water stress makes stalks stringy with a strong flavor, and hot, dry conditions at harvest can make them tough and bitter. Oregon State University Extension adds that stalks left too long in the garden develop pith inside the petioles, so harvest before that happens.
Should you cut outer celery stalks or harvest the whole plant?
Either works. Utah State University Extension says to remove the outer petioles once they’re a foot or more long and let the plant keep growing, or wait until the whole head is 3 inches or more across and harvest it all at once.
Let the planner place them
Plan My Garden is free to start: enter your zip code, draw your beds, pick celery and everything else you want to grow, and it places each plant at square-foot spacing and builds a planting schedule from your frost dates.
Related: Square Foot Gardening Chart · Seed Starting Calendar · 4×4 Raised Bed Garden Layout · How Many Parsley Plants per Square Foot? · How Many Cilantro Plants per Square Foot?
