Last Updated on September 17, 2026
How Many Radish Plants per Square Foot?
16 radish plants fit in one square foot, spaced on a 3 inch grid, 4 rows of 4. That is for small globe radishes like Cherry Belle. Long or daikon and winter radishes need more room, 4 to 6 inches apart, which works out to 9 or 4 per square instead.
The spacing pattern by type
| Type | Extension spacing | Per square |
|---|---|---|
| Small globe (Cherry Belle, Plum Purple) | 2 to 3 inches, in all directions on a bed (Illinois Extension) | 16 (3 in) |
| Long, daikon or winter radishes | 4 to 6 inches (University of Minnesota Extension) | 9 (4 in) to 4 (6 in) |
| 2 x 4 bed (8 squares) | up to 128 small globe radishes |
| 4 x 4 bed (16 squares) | up to 256 |
| 4 x 8 bed (32 squares) | up to 512 |
| 3 x 6 bed (18 squares) | up to 288 |
16 per square is the number on my square foot gardening chart, and the Plan My Garden planner uses the same one. Carrots share it too; see how many carrot plants fit per square foot. These are grid maximums for small globe types; a 2×4 raised bed garden layout holds up to 128 and suits sowing every few days.
Why 20 or more per square is pushing it
You will see radish counts as high as 20 to 22 per square quoted online. The arithmetic works: 20 per square is about 2.7 inches apart, 22 is about 2.6 inches, both still inside Illinois Extension’s 2 to 3 inch bed spacing. The problem is margin. University of Minnesota Extension thins radishes to about 2 inches and warns that plants set too close together do not develop harvestable roots at all, they grow all top. 20 or 22 per square leaves almost no room before that failure point and demands exact thinning across the whole square. 16 per square, at 3 inches, sits comfortably inside the recommended range instead.
Succession sowing for a steady supply
| Source | Resow interval |
|---|---|
| University of Maryland Extension | every 5 days |
| Utah State University Extension | every 10 days |
| Illinois Extension | every 10 to 14 days |
Radishes mature so fast that one sowing does not last. The Plan My Garden planner lists radishes at 25 days to maturity, one of the fastest crops it tracks, and all three extension offices above recommend small, staggered sowings instead of one large planting, though they differ on how often to resow. At 25 days to maturity, resowing every 5 to 14 days keeps 2 to 5 sowings growing at once: sow a new square each time you harvest one.
Radishes are a favorite of mine for that speed. In my own beds I plant several rounds starting roughly 6 weeks before my last frost, with the first batch usually ready in about 22 days, then I often follow with a planting of beans.
Why radishes bolt or grow all top and no root
University of Minnesota Extension’s disorder note covers one failure plainly: radishes planted too close together do not develop harvestable roots, they put energy into top growth instead, which is why the chart’s 3 inch spacing matters. The other failure is heat. Utah State University Extension’s own frequently asked questions blame all top and no root on planting too thickly without thinning, temperatures too hot for the variety, or too much shade. Separately, high summer heat triggers a flower stalk, bolting, and leaves the roots tasting bitter and hollow, which Minnesota Extension also blames on slow growth in hot weather.
Planting the square
- Sow seed 1/4 to 1/2 inch deep, the depth University of Maryland Extension and Illinois Extension give for small globe types; Minnesota Extension plants daikon types up to 1 inch deep.
- Space seed about 1 inch apart, or scatter evenly across the square, then thin once seedlings are up.
- Thin small globe types to 2 to 3 inches. Thin daikon and winter types to 4 to 6 inches.
- Keep the soil evenly moist. Uneven watering, a dry spell then a heavy soak, is what Utah State University Extension blames for cracked, split roots.
- Check the square often near the planner’s 25 day mark. Illinois and Minnesota Extension both warn radishes left too long turn pithy and hollow.
When to plant radishes
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 | No separate week. Radishes are direct sown in the planner. |
|---|---|
| Direct sow | 8 weeks before to 4 weeks after your last frost |
| Days to maturity | 25 days, one of the fastest on my vegetable days to maturity chart |
| Frost tolerance | Semi-hardy, between hardy and tender on my vegetable frost tolerance chart |
That window matches the extension offices, without naming a date: Maryland Extension sows as soon as the soil can be worked in spring, and again in fall. Utah State and Minnesota Extension plant a spring crop a few weeks before the last frost and a second in late summer to avoid heat. Use your own last frost date on Plan My Garden or the seed starting calendar to turn these weeks into a planting day.
Germination, soil, and where to get seed
From my Seed Germination Temperature Chart: radishes germinate from 40°F, do best at 65-85°F, and the maximum is 95°F. At 41°F seed can take 29 days to emerge; at 86°F just 3. They also want full sun and evenly moist, loose soil; Minnesota Extension calls for well drained soil, pH 6 to 7, and warns drought stress gives the roots poor flavor and tough texture. Illinois Extension notes radish is in the cabbage family, the same family as my cabbage spacing guide. Turnips are a similarly fast root crop worth succession sowing the same way.
Wood Prairie’s organic radish seed includes Cherry Belle (25 days, small globe), Plum Purple (27 days, small globe) and Watermelon Radish (60 days, larger rooted, for fall harvest and storage). The globe types fit the 3 inch, 16-per-square spacing; the 60 day type needs the wider 4 to 6 inch spacing. Code PMG5 takes 5 percent off.
Quick questions
How many radish plants fit in a 4×8 raised bed?
Up to 512 small globe radishes on the square foot grid, 16 per square on a 3 inch spacing. Long or daikon and winter types need more room, 4 to 6 inches apart, which fits 128 to 288 in the same bed.
What is radish spacing in square foot gardening?
16 small globe radishes per square, on a 3 inch grid. Long or daikon and winter radishes need 4 to 6 inches apart instead, which is 9 or 4 per square.
Can you plant more than 16 radishes per square foot?
Not by much. Getting to 20 or 22 per square needs roughly 2.6 to 2.7 inches between plants, close to the 2 inch minimum spacing University of Minnesota Extension gives for thinning radishes, with little margin before the crowding disorder it describes: roots that never develop.
Why do radish plants grow all top and no root?
Utah State University Extension points to three causes: planting too thickly without thinning, temperatures too hot for the variety, or too much shade. University of Minnesota Extension adds that radishes set too close together are the classic case of top growth with no harvestable root.
Let the planner place them
Plan My Garden is free to start: enter your zip code, draw your beds, pick radishes 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 · 10 Crops You Can Direct Sow Before Your Last Frost · How Many Carrot Plants per Square Foot?
