Free Growli tool
Plant spacing calculator
— how many fit your bed.
Pick a crop and enter your bed width and length in inches or centimetres. The calculator returns plant-to-plant and row-to-row spacing from US extension and RHS guidance, the total plants that fit in a standard row layout, and the higher count you can squeeze in with square-foot gardening.
Spacing baselines from Cornell, Iowa State, Utah State Extension, and the Royal Horticultural Society. Square-foot figures from Mel Bartholomew.
Spacing for tomatoes (indeterminate)
24 inches apart in rows 48 inches apart
Indeterminate (vining) tomatoes need 24 inches between plants and 48 inches between rows. Spacing below 18 inches roughly quadruples foliar disease risk.
Plants per row
2
across 48 inches
Rows
2
down 96 inches
Total plants
4
standard row layout
Square-foot gardening alternative
In Mel Bartholomew's intensive system you grow 1 tomatoes (indeterminate) per square foot in a deep raised bed with no walking paths between rows.
Your bed is 32.0 square feet, so you could squeeze in roughly 32 plants — about 800% of standard row spacing. Intensive layouts need richer soil and more consistent watering.
Companion suggestion
Tuck basil 12 inches between plants — peer-reviewed pairing.
Save your bed layout to Growli
The Growli app builds your full bed plan from your crop list — applies the right spacing per crop, flags companion or antagonist conflicts, and tracks how many plants you actually sowed against the plan.
Save to Growli →Why spacing matters more than seed count
New gardeners almost always plant too close. The seed packet says "sow thinly" and then you thin reluctantly — leaving a tomato every 12 inches because pulling one feels wasteful. Cornell research showed those crowded tomato beds suffer roughly 3.7x more foliar disease and produce 22% smaller fruit. The plants stay alive but the overall harvest is worse than if you had pulled half of them.
The calculator uses extension-standard spacing — Cornell, Iowa State, Utah State, and the RHS — which assumes you want healthy plants, full airflow, and the harvest that comes with both. Square-foot gardening pushes denser numbers but only works in a deep raised bed with consistent watering and richer soil to back it up.
What this tool does not capture. Walking paths between beds (add 18-24 inches), your specific soil fertility, or how many plants of each you actually want for your household. For the full bed plan with rotation and companion-conflict checking, the Growli app builds it from your crop list.
Frequently asked questions
How do I know how far apart to plant a crop?
Spacing depends on the mature size of the plant and how much airflow the foliage needs to dodge disease. For most vegetables the seed packet or extension service gives plant-to-plant spacing (how far apart individual plants sit in a row) and row-to-row spacing (how far apart the rows are). The calculator pulls these from Cornell, Iowa State, Utah State, and RHS guidance — overall standards rather than optimistic packet figures.
What happens if I plant too close?
Crowded plants compete for water and nutrients, but the bigger problem is foliar disease. Cornell research on tomato spacing under 18 inches showed roughly 3.7x more foliar disease and a 22% drop in average fruit weight. The plants stay smaller and the fruit drops in size — you do not actually get more total harvest, just more risk.
Is square-foot gardening always tighter?
Yes — Mel Bartholomew built square-foot gardening around dense plantings in 4x4 raised beds with no walking paths. It works because deeper soil, more compost, and more frequent watering compensate for the lack of row access. For tomatoes and peppers (one plant per square foot), the spacing is similar to standard rows; for small crops (carrots, radishes, onions), square-foot packs 9-16 plants in the same space.
How wide should my walking paths be?
Plan 18-24 inches between beds for one-person access and 30-36 inches if you push a wheelbarrow through. Make beds 4 feet wide at most so you can reach the middle from either side. The calculator focuses on the bed itself — add path width on top when you plan the full garden footprint.
Can I plant smaller and harvest baby crops?
Yes — most leafy greens (lettuce, kale, spinach, chard) and herbs (basil, cilantro) work well at half the standard spacing if you plan to cut them young and let the rest mature. Root crops (carrots, beets) and head-formers (cabbage, broccoli) need their full spacing — crowding produces forked or undersized plants.
How is this different from the Growli app?
The calculator gives you spacing for one crop at a time. The Growli app builds your full bed plan from your crop list — applies the right spacing for each crop, flags companion or antagonist conflicts before you sow, and tracks how many you actually planted against the plan so the harvest projections stay honest.