Calculator
Example data table
| Scenario | Bench setup | Space settings | Pot / tray settings | Key outputs |
|---|---|---|---|---|
| Seedling trays | 4 rectangular benches, 2.4x1.2 (m), 1 tier | Usable 90%, edge 2 cm | Tray 54x28 cm, gap 1 cm | Usable area ~ 12.4 m^2, trays ~ 120 |
| Potted herbs | 6 rectangular benches, 8x4 (ft), 2 tiers | Usable 88%, edge 1 in | Pot 4 in, spacing 1 in | Usable area ~ 331 ft^2, pots ~ 840 |
| Corner workstation | 2 L-shaped benches, legs 2.0 & 1.6 (m), width 0.8 (m) | Usable 85%, edge 3 cm | Pot 10 cm, spacing 2 cm | Usable area ~ 4.2 m^2, pots ~ 220 |
| Round display | 1 circular bench, diameter 1.5 (m), 1 tier | Usable 92%, edge 2 cm | Pot 10 cm, spacing 2 cm, factor 0.85 | Usable area ~ 1.6 m^2, pots ~ 95 |
Formula used
- Rectangular bench: Area = Length x Width.
- Circular bench: Area = pi x (Diameter/2)^2.
- L-shaped bench: Area = (LegA x Width) + (LegB x Width) - (Width x Width).
- Effective area: Reduce outer edges by edge clearance, then recompute.
- Usable growing area: EffectiveArea x (Usable%/100) x BenchCount x Tiers.
- Pots (grid): Rows = floor(EffectiveLength/(PotDiameter+Spacing)), Columns = floor(EffectiveWidth/(PotDiameter+Spacing)).
- Pots (circle): Pots ~ floor((EffectiveArea/Pitch^2) x PackingFactor).
- Trays: Try both orientations and choose the larger fit.
How to use this calculator
- Select units and bench shape.
- Enter dimensions, bench count, tiers, and usable percentage.
- Add edge clearance for realistic working space.
- Choose capacity mode, then enter pot or tray sizes.
- Press Calculate to show results above the form.
- Use Download CSV or Download PDF for records.
Planning notes
Capacity planning for seasonal runs
Bench capacity influences sowing dates, irrigation loads, and labor planning. A small change in edge clearance or spacing can reduce capacity by 5–15% on narrow benches. Track usable percentage consistently across rooms, then compare usable area per tier to your weekly transplant targets for a realistic production plan.
Usable percentage and real-world obstructions
Use the usable percentage to account for posts, end rails, fan housings, and tool zones. Many operations use 85–92% for rectangular benches and slightly less for corner layouts. If your measured outputs differ, adjust usable percentage instead of changing bench dimensions so the model stays aligned with site measurements.
Pot spacing, airflow, and disease pressure
Spacing is a crop-health control, not just a layout detail. Increasing spacing improves airflow and lowers leaf wetness duration, which can reduce fungal risk in dense canopies. For 10 cm pots, moving from 1 cm to 2 cm spacing increases pitch by 9% and can cut grid capacity by roughly the same margin on rectangular benches.
Tray handling and orientation efficiency
Trays often fit better when rotated, especially on benches near standard widths. The calculator checks both orientations with a handling gap so you can select the most efficient layout. For plug trays, prioritize a small gap that still allows lifting and watering access to prevent breakage and uneven moisture patterns.
Example data for a quick layout decision
Use the snapshot below as a starting point, then refine with your exact tray and pot sizes. The goal is to standardize a repeatable setup so staff can reset benches quickly between crops.
| Room | Benches | Tiers | Usable% | Clearance | Target | Result check |
|---|---|---|---|---|---|---|
| Propagation | 6 benches, 2.4x1.2 m | 1 | 90% | 2 cm | Plug trays | Confirm trays per tier before seeding |
| Finishing | 8 benches, 8x4 ft | 2 | 88% | 1 in | 4 in pots | Verify aisle access for carts |
FAQs
1) Why do my counts differ from a hand layout?
This tool estimates packing with clearance, gaps, and usable percentage. Real benches have irregular edges, fixed supports, and handling preferences. Calibrate usable percentage and edge clearance until results match a measured bench.
2) What usable percentage should I start with?
For clean rectangular benches, 88–92% is common. For benches with brackets, end rails, or tool zones, start near 85%. Adjust after comparing to a measured bench-top layout.
3) Should pot spacing include airflow space?
Yes. Use spacing as the extra gap between pot edges. More spacing improves airflow and reduces canopy humidity, but lowers capacity. Pick spacing that matches your crop health and watering strategy.
4) How are circular bench pot counts calculated?
Circular benches use an area-based estimate: effective area divided by pitch squared, multiplied by a packing factor. The packing factor approximates wasted space around curved edges and typical placement patterns.
5) Why does the tool check tray orientation?
Trays can fit better when rotated, especially on benches near standard widths. The calculator tests both orientations with the chosen gap and uses the larger result for a practical layout.
6) How should I handle mixed pot sizes?
Run separate calculations per pot size and keep notes in the exported CSV or PDF. For mixed crops on one bench, use the larger pot diameter to avoid overestimating capacity.
7) Can I use tiers for shelves or rolling racks?
Yes. Set tiers to the number of usable levels. Keep edge clearance and usable percentage realistic for each level, since upper shelves often need larger handling gaps and have more obstructions.