Start with the source range and your harvest system
The linked guide range applies to mature leaf or head lettuce: 8 to 12 inches apart within rows, with rows 12 to 18 inches apart. That range is for plants grown to a mature stage, not for dense baby-leaf cutting. If your plan is to cut baby leaves densely, treat it as a separate system rather than forcing it into this mature-plant spacing.
Within the source range, choose one center interval for your plan and label it. The worked example selects 12 inches, the upper end of the within-row range, for mature leaf or head lettuce. That is a scenario choice, not a claim that 12 inches is best for every garden. Record the interval you choose so the marking and counting steps agree.
- Decide whether the bed is for mature leaf or head lettuce or for dense baby-leaf cutting.
- If growing mature leaf or head lettuce, select one within-row interval from 8 to 12 inches and write it down.
- Select a separate row-to-row interval from 12 to 18 inches, or state that adjacent-row spacing will be decided separately.
Source context: Utah State University Extension
Mark final plants in one measured row
Measure the row length first. The example row is 96 inches long. It uses 6-inch margins at both ends and 12-inch centers between final plants. The first center falls at 6 inches and the last at 90 inches, giving 8 counted final plants. The counted item is final plants, not seeds, seedlings, thinnings or harvests.
This is a geometrical example for one row, not a complete garden layout. It does not set adjacent-row spacing, access paths, supports or the mature habit of neighboring crops. Those choices must be made separately for your site. The linked row calculator can count this exact length, center interval and both end margins in inches or centimeters.
- Measure the row length in inches or centimeters.
- Choose the center interval and both end margins, then enter them in the row calculator.
- Mark each calculated center and count final plants only, not seeds or thinnings.
Source context: Utah State University Extension
Separate sowing and thinning from final spacing
Sowing, thinning and initial planting are not the same as the final plant count. The 8 plants in the example are the plants you intend to keep at the marked centers. Earlier sowing or thinning may involve more plants, but those are not counted as final plants.
Use the marked centers to check the plan before planting. If the row length, center interval or end margins change, recalculate rather than adjusting the count by eye. Keep the chosen interval and the counted item written beside the row so the plan remains clear.
- Label the row with its length, center interval and end margins.
- Keep a separate note for sowing or thinning and do not add those to the final plant count.
- Recalculate if any measured value changes.
Source context: Utah State University Extension
Decide the rest of the layout separately
One row does not define the whole garden. Access, supports, adjacent rows and mature habit need their own decisions. The source supplies a row-to-row range of 12 to 18 inches for mature leaf or head lettuce, but it does not supply path widths, support distances or spacing for other crops.
Check that the chosen within-row interval and row-to-row interval fit the space you have. Keep the geometrical example separate from crop advice: the example shows how the count is calculated, while the source range describes mature leaf or head lettuce spacing.
- Choose adjacent-row spacing separately from the within-row interval.
- Check access and any supports against your own layout.
- Confirm that neighboring crops and mature habit are planned outside this one-row example.
Source context: Utah State University Extension
Check your measured example
One measured 96-inch row, with selected 12-inch centers and 6-inch margins at both ends. Count 8 final plants.
Reference and growing system: USU describes mature leaf or head lettuce 8–12 inches apart within rows 12–18 inches apart. Dense baby-leaf cutting is a separate harvest system.
| Quantity | Calculated result |
|---|---|
| Usable row length (in) | 96 |
| Selected center spacing (in) | 12 |
| Margin at each row end (in) | 6 |
| Positions in this row | 8 |
| First center from row start (in) | 6 |
| Last center from row start (in) | 90 |
| What is being counted | final plants |
The worked example is a geometrical count for one 96-inch row with 12-inch centers and 6-inch margins at both ends. It yields 8 final plants, with the first center at 6 inches and the last at 90 inches. The 12-inch choice sits within the source range for mature leaf or head lettuce, but the example does not set adjacent-row spacing or describe an entire garden layout.
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
- Harvest system is labeled as mature leaf or head lettuce, not dense baby-leaf cutting.
- One within-row interval from 8 to 12 inches is recorded.
- Row length, center interval and both end margins are entered in the row calculator.
- The count is labeled final plants, not seeds or thinnings.
- Adjacent-row spacing, access and supports are decided separately from the one-row example.
Questions that come up while planning
What spacing does the source give for mature leaf or head lettuce?
USU describes mature leaf or head lettuce 8 to 12 inches apart within rows 12 to 18 inches apart. Dense baby-leaf cutting is a separate harvest system.
How does the 96-inch example count 8 final plants?
With 6-inch margins at both ends and 12-inch centers, the first center is at 6 inches and the last at 90 inches. That gives 8 counted final plants.
Does one marked row set the whole garden layout?
No. The example is one row only. Access, supports, adjacent rows and mature habit must be chosen separately, and the source does not supply those distances.
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 Lettuce in Your GardenUtah State University Extension