Read the source range before you choose
USU supplies a range, not a single spacing. Within a row, thin radishes to 1–2 inches apart; keep rows 10–12 inches apart. The within-row figure describes retained plants after thinning, not the distance at which you sow seed. Sowing more thickly and then thinning is a separate step from the final stand you mark and count.
Choose one within-row value for your plan and label it clearly. A tighter value within the range means more retained plants per foot of row; a wider value means fewer. The row interval is also a choice within 10–12 inches, and it is not the same decision as the within-row spacing.
- Write down the within-row spacing you selected from the 1–2 inch range.
- Write down the row interval you selected from the 10–12 inch range.
- Label both as thinning targets for retained plants, not sowing distances.
Source context: Utah State University Extension
Worked example: one 96-inch row at 2-inch centers
The worked example is a geometrical count, not a crop recommendation. It uses one measured row 96 inches long, a selected 2-inch center spacing, and 1-inch margins at both ends. With those inputs, the first retained plant center falls at 1 inch and the last at 95 inches, giving 48 counted positions.
The counted item is retained plants after thinning. The 2-inch value sits at the wider end of USU's 1–2 inch thinning range, and the example applies it to a single row. It does not set the distance between adjacent rows, and it does not describe an entire garden layout. A different within-row value, row length or end margin would change the count.
- Measure the row length in inches or centimeters.
- Set the center spacing and both end margins in the same unit.
- Count positions along that one row and record the result as retained plants.
Source context: Utah State University Extension
Mark the stand and plan the rest separately
Marking retained plants is easiest after thinning, when each remaining plant has a clear position. Mark centers along the row using your selected within-row spacing, and keep the end margins consistent so the first and last marks are not crowded against the row ends.
One row is not a whole bed or garden plan. Decide separately how much access space you need for tending and harvesting, whether any supports or structures are required, how adjacent rows relate to the 10–12 inch row interval, and how the mature habit of the plants affects your layout. The linked guide does not give distances for those choices, so record them as your own decisions rather than treating them as sourced figures.
- Thin first, then mark each retained plant center along the row.
- Check that end margins match the values used in your count.
- Record access, support and adjacent-row decisions separately from the row count.
Source context: Utah State University Extension
Use the row calculator for this exact count
The linked row calculator can count this exact row length, center interval and both end margins, in inches or centimeters. Enter the measured length, the selected center spacing and the margin at each end, then read the number of positions. Keep the counted item labeled as retained plants after thinning so the result is not confused with seed sown or seedlings emerged.
If you change the within-row spacing within USU's 1–2 inch range, the count changes even though the row length stays the same. Recheck that the opening scenario, the worked example and the calculator inputs all use the same values.
- Enter the row length in inches or centimeters.
- Enter the selected center interval and both end margins in the same unit.
- Confirm the result is labeled retained plants and matches your written plan.
Source context: Utah State University Extension
Check your measured example
One measured 96-inch row, with selected 2-inch centers and 1-inch margins at both ends. Count 48 retained plants.
Reference and growing system: USU’s radish Planting and Spacing section gives thinning to 1–2 inches within rows 10–12 inches apart. This example counts retained plants after thinning.
| Quantity | Calculated result |
|---|---|
| Usable row length (in) | 96 |
| Selected center spacing (in) | 2 |
| Margin at each row end (in) | 1 |
| Positions in this row | 48 |
| First center from row start (in) | 1 |
| Last center from row start (in) | 95 |
| What is being counted | retained plants |
The worked example is a geometrical count for one 96-inch row with 2-inch centers and 1-inch margins at both ends, producing 48 retained plants. The 2-inch value is a selected point within USU's 1–2 inch thinning range. It does not set row-to-row distance, describe a full garden layout, or predict crop performance.
Count this row in the spacing calculator ↗Example inputs explain the method. Review the source context, chosen cultivar and actual site before planting or ordering.
Your before-you-plant checklist
- Within-row thinning target selected and labeled from the 1–2 inch range.
- Row interval selected separately from the 10–12 inch range.
- Row length, center spacing and both end margins entered in the same unit.
- Count labeled as retained plants after thinning, not seed sown.
- Access, support and adjacent-row decisions recorded separately from the row count.
Questions that come up while planning
Does the 1–2 inch figure mean I should sow radish seed 1–2 inches apart?
No. USU gives 1–2 inches as the thinning target within rows, so it describes retained plants after thinning. Sowing density is a separate decision not covered by that figure.
Does the 96-inch example tell me how far apart to place radish rows?
No. The example counts retained plants along one row using a 2-inch center spacing and 1-inch end margins. Row-to-row distance is chosen separately from USU's 10–12 inch row interval.
Why does the example count 48 plants?
With 1-inch margins at both ends of a 96-inch row, plant centers run from 1 inch to 95 inches. At 2-inch centers, that gives 48 positions, counted as retained plants after thinning.
Sources & method
Horticultural guidance is linked to its original source and regional context. Geometry and unit conversions are calculated separately. Read how we prepare and check a page.
- How to Grow Radishes in Your GardenUtah State University Extension