Read the source range before choosing a number
Treat 12–18 inches as the in-row range and 24–36 inches as the between-row range. The source does not name one best distance for every cultivar or head size, so record your chosen value and the reason you chose it. A tighter in-row choice sits at the low end of the range; a wider choice sits at the high end. Neither is a recommendation for a particular cultivar unless you can tie the choice to the cultivar and head-development goal you are actually growing.
Keep the two directions separate. In-row spacing controls where retained plants sit along one line. Between-row spacing controls how adjacent rows relate to each other. Choosing an in-row number does not settle the between-row number, and one measured row does not describe the rest of the garden.
- Write down the in-row range and between-row range before measuring.
- Choose one in-row value within 12–18 inches and label the scenario it applies to.
- Record the cultivar and head-development goal that informed that choice, or state that the choice is provisional.
Source context: Utah State University Extension
Mark retained plants, not every seed or seedling
Sowing, thinning and initial planting are earlier decisions than marking the plants you will retain. A seed sown at a chosen interval is not yet a retained plant, and a thinned seedling is not a final position. Marking retained plants means fixing the centers of the plants you intend to keep and checking that each mark falls within the measured row and inside the end margins.
Use the counted item precisely: the example counts retained plants, not seeds, seedlings, heads or gaps. If you change the selected center spacing or either end margin, the count changes even when the row length stays the same. Keep the chosen spacing and margins visible beside the marks so the plan can be checked later.
- Measure the row length first and note the unit.
- Set the selected center spacing and both end margins before placing any marks.
- Mark only the retained-plant centers, then count those marks rather than counting seeds or seedlings.
Source context: Utah State University Extension
Worked example: one 144-inch row at 18-inch centers
The worked example uses one measured row of 144 inches, a selected center spacing of 18 inches, and 9-inch margins at both ends. The first retained-plant center falls at 9 inches and the last at 135 inches, giving 8 counted positions. This is a geometrical example of counting retained plants along one row. It is not crop advice that 18 inches is the right spacing for your cultivar, and it is not a complete garden layout.
The 18-inch value sits at the high end of the in-row range, so label it as the selected scenario rather than as a general rule. The 9-inch end margins are part of this example only; the source does not supply end-margin distances. The linked row calculator can count this exact length, center interval and both end margins in inches or centimeters. It does not decide between-row spacing, access, supports or adjacent-row placement for you.
- Enter the 144-inch row length, 18-inch center spacing and 9-inch margins at both ends in the row calculator.
- Confirm the calculator reports 8 retained plants with the first center at 9 inches and the last at 135 inches.
- Label the result as one row at a selected 18-inch spacing, not as a whole-garden plan.
Source context: Utah State University Extension
Choose the rest of the layout separately
A single row leaves several choices open. Decide between-row spacing within the 24–36 inch range, and decide how you will reach the plants for tending and harvest. Consider whether adjacent rows, supports or the mature habit of the cultivar affect the space you need. The source does not give distances for access paths, supports or mature spread, so do not invent them; record those choices as separate planning decisions.
If you plan more than one row, repeat the measured-row count for each row and check the between-row distance against your chosen value. Keep the in-row marks and the between-row layout on the same plan so the two decisions can be compared. A generic square grid is not a cauliflower row layout, and it does not replace the in-row and between-row ranges.
- Choose a between-row value within 24–36 inches and label it separately from the in-row choice.
- Note access, support and mature-habit considerations without assigning unsupplied distances.
- Repeat the row count for each additional row and check the between-row spacing on the plan.
Source context: Utah State University Extension
Check your measured example
One measured 144-inch row, with selected 18-inch centers and 9-inch margins at both ends. Count 8 retained plants.
Reference and growing system: USU gives cauliflower plants 12–18 inches apart within rows 24–36 inches apart. Cultivar and head-development goal affect the chosen distance.
| Quantity | Calculated result |
|---|---|
| Usable row length (in) | 144 |
| Selected center spacing (in) | 18 |
| Margin at each row end (in) | 9 |
| Positions in this row | 8 |
| First center from row start (in) | 9 |
| Last center from row start (in) | 135 |
| What is being counted | retained plants |
The worked example is a geometrical count, not crop advice. A 144-inch row with 18-inch centers and 9-inch margins at both ends places the first center at 9 inches and the last at 135 inches, giving 8 retained plants. The 18-inch value is a selected scenario within USU's 12–18 inch in-row range; the 9-inch margins come from the example, not the source. The count does not set between-row spacing, access, supports or adjacent-row placement.
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
- The chosen in-row value is within 12–18 inches and labeled with its scenario.
- The chosen between-row value is within 24–36 inches and recorded separately.
- Marks represent retained plants, not seeds, seedlings or thinned plants.
- The row length, center spacing and both end margins are recorded in one unit.
- The 144-inch example is labeled as one row, not a whole-garden layout.
Questions that come up while planning
What in-row spacing does USU give for cauliflower?
USU gives cauliflower plants 12–18 inches apart within rows 24–36 inches apart. Cultivar and head-development goal affect the chosen distance, so record which value you selected and why.
Does the 144-inch example recommend 18-inch spacing?
No. The example is a geometrical count of retained plants along one measured row using a selected 18-inch center spacing and 9-inch end margins. It does not establish 18 inches as the right spacing for a particular cultivar.
Does one counted row describe my whole garden layout?
No. One row fixes retained-plant centers along a single line. Between-row spacing, access, supports, adjacent rows and mature habit must be chosen separately, and the source does not supply distances for access or supports.
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 Cauliflower in Your GardenUtah State University Extension