Library · Structures, greenhouse & energy
Capacity Calculator.
Capacity Calculator
Plants per square foot, plants per room, and the spacing reality behind those numbers.
Capacity assumptions
| Method | Plants/ft² (typ) | Spacing (typ) | Container |
|---|---|---|---|
| Cannabis SOG | 4–9 | 4–6" | Solo cup → 1-gal |
| Cannabis medium training | 1–2 | 10–14" | 3–5 gal |
| Cannabis large plants | 0.25–0.5 | 24–36" | 7–15 gal |
| Lettuce NFT | 3–6 | 5–8" | NFT channel slot |
| Lettuce raft | 2–4 | 6–10" | Net pot in raft |
| Microgreens trays (10×20) | 0.36 trays/ft² typical | Tray = 1.4 ft² | 10×20 standard |
| Tomato greenhouse | 0.4–0.8 | 14–18" | Slab / 5+ gal |
| Strawberry vertical | 4–10 (vertical stacking) | 8" vertical | Tower / hydroponic slot |
| Herbs in pots | 1–4 | 6–12" | 1–3 gal |
| Mushroom shelf | 0.5–1 block/ft² | Shelf-stack capable | 5 lb substrate block |
Beyond capacity — what limits you
Plant count is rarely the actual capacity constraint. The real constraints are:
- Light coverage — fixtures cover defined areas. More plants beyond fixture coverage = un-lit canopy = reduced yield per added plant. Match your plant count to your fixtures, not to your floor space.
- HVAC capacity — more plants = more transpiration = more humidity = more dehumidification load. Insufficient HVAC limits how many plants you can grow without VPD problems.
- Substrate / fertigation — running 100 pots requires labor or automation; manual hand-watering caps at maybe 30-50 pots before becoming impractical.
- Workflow — every plant needs occasional inspection, training, and harvest. Tightly-packed canopies are hard to work; SOG growers often regret going too dense by week 4 of flower.
- Quarantine and inspection paths — leave room to move plants out, inspect from multiple sides, and isolate problem plants.
- Regulations — many cannabis jurisdictions cap plant counts per facility regardless of square footage.
The recommendation above gives a low / typical / high range. The "typical" is what most operations end up with after their first cycle's reality check. The "high" requires excellent training, experience, and infrastructure. The "low" leaves room for plants to express; often produces the highest per-plant yield even if total facility yield is lower than max.
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