Introduction to vertical farm LED yield estimates
In a vertical farm, LEDs stand in for the sun, so every lighting choice affects both crop growth and the electric bill. This calculator turns PPFD, photoperiod, growing area, and LED efficacy into daily photon delivery, a rough fresh-yield estimate, lighting energy use, and daily cost for stacked growing systems.
Use it for quick planning when you want to compare a brighter-but-shorter schedule against a longer light cycle, test a more efficient fixture, or see how a different power rate changes the economics. It is a planning tool rather than a substitute for crop trials, but it is useful for bracketing scenarios before you commit to a lighting recipe.
Why PPFD and DLI matter in vertical farms
A vertical farm does not get free photons from daylight; every usable photon has to come from a fixture aimed at the canopy. That is why PPFD and DLI matter so much in stacked growing systems: they describe how much light reaches the crop at a moment and how much light accumulates over the full day. Because energy is billed separately from biomass, the same lighting plan also determines how many kilowatt-hours the facility burns.
LEDs sit at the center of that balance. A basil tray or lettuce raft grows because chloroplasts capture photons, but the fixtures that deliver those photons draw grid electricity and create heat. Efficiency in µmol/J tells you how many photons you get for each joule, which lets the calculator connect crop light dose to operating cost in a way that makes sense for vertical farm planning.
The calculator converts intensity into a canopy-wide daily photon total. It multiplies PPFD by the lit area and by the number of seconds the lights stay on, then converts that total from micromoles to moles. That lets you think about the whole rack or room rather than only a per-square-meter reading, which is especially helpful when comparing one bay of shelves with another.
Once you have moles of photons, you can attach an estimated yield factor. Many leafy crops respond almost linearly over a useful range, so a grams-per-mole assumption gives a practical first-pass harvest estimate. The same total photon number, divided by fixture efficacy, also becomes energy use and then cost. For farms running on thin margins, that chain from photons to dollars is often the real decision point.
How to use the vertical farm LED yield calculator
- Enter growing area (m²): the total canopy footprint lit by the LEDs across all tiers or benches in the farm.
- Enter PPFD (µmol/m²/s): the average canopy PPFD during the light period, ideally from measurements taken at plant height.
- Enter photoperiod (hours/day): the number of hours each day that the LEDs run; longer hours raise daily photon delivery without changing intensity.
- Enter yield per mol (g/mol): a planning factor for how many grams of fresh mass your crop produces per mole of photons delivered.
- Enter LED efficiency (µmol/J): fixture efficacy. Higher values mean more photons for the same electricity input.
- Enter electricity price ($/kWh): your blended lighting rate or the rate that applies during the hours you run the lamps.
- Select Calculate Yield and Energy to see daily photons, projected harvest, lighting energy use, and electricity cost for the scenario.
Tip: If you already manage lighting by DLI targets, use that target to back into PPFD and then test how a different photoperiod or fixture efficacy changes the same crop dose.
Formula and unit assumptions for vertical farm lighting
This vertical farm lighting model uses standard photon and energy conversions to turn canopy PPFD into daily light dose, projected yield, and cost. PPFD is in µmol/m²/s, area is in m², and photoperiod is in hours/day.
- Total photons per day (µmol/day):
PPFD × Area × Photoperiod × 3600 - Total photons per day (mol/day):
Total_µmol ÷ 1,000,000 - Projected yield (kg/day):
(mol/day × (g/mol)) ÷ 1000 - Energy use (kWh/day):
(Total_µmol ÷ (µmol/J)) ÷ 3,600,000 - Daily electricity cost:
kWh/day × $/kWh
Many growers manage by DLI in mol/m²/day. This calculator extends that idea to the full lit footprint so you can estimate the total photon load your racks receive each day. The MathML expression below shows the same area-wide conversion directly:
where is the number of seconds of illumination per day.
Worked example: a leafy-greens rack under LED lights
For a straightforward leafy-greens rack in a vertical farm, suppose you run the following inputs:
- Area: 100 m²
- PPFD: 400 µmol/m²/s
- Photoperiod: 16 h/day
- Yield factor: 3 g/mol (fresh mass per mol of photons, planning value)
- LED efficiency: 2.5 µmol/J
- Electricity price: $0.10/kWh
With those settings, the calculator estimates roughly 2,304 mol/day of photons delivered, about 6.91 kg/day of projected fresh mass, around 71.11 kWh/day of lighting energy, and a daily electricity cost near $7.11/day. If you increase efficacy (µmol/J) while keeping PPFD and hours constant, the photon dose stays the same but kWh and cost drop.
How to interpret vertical farm lighting results
The first result, daily photons delivered, tells you how much light dose the whole canopy receives. That makes it easier to compare a low-PPFD, long-day plan with a high-PPFD, short-day plan because the calculator collapses them into one daily total. When you compare scenarios, remember that plants react to both total dose and delivery pattern.
The second result, projected harvest, is a planning estimate rather than a promise. The grams-per-mole input is where your crop and cultivar experience enters the model. If the number seems too high, the most likely issue is that your chosen yield factor is too generous for that variety, spacing, climate, or harvest timing. If it seems too low, your facility may be converting photons into biomass better than the conservative starting factor suggests. The best calibration loop is still the same: record harvest mass, compare it to photons delivered, and adjust the factor until it matches your farm.
The last two outputs, lighting energy use and daily electricity cost, turn the crop plan into an operating expense. A grower may accept more kWh if the extra light shortens turnover, improves quality, or makes the harvest window more predictable. In other cases, a small reduction in PPFD or a move to higher efficacy can improve margins without materially hurting saleable yield. That is why the calculator works best when you run side-by-side scenarios rather than treating any single result as fixed truth.
Typical vertical farm planning values (starting points)
The table below gives rough starting factors for vertical farm crops in grams of fresh mass per mole of photons. They are not universal constants: cultivar, CO2, temperature, nutrient delivery, spacing, and harvest stage all move the number up or down. The safest workflow is to start conservatively, then replace the assumption with your own observed data once you have a few harvests.
| Crop | Fresh mass per mol (g/mol) |
|---|---|
| Lettuce | 3.0 |
| Basil | 2.5 |
| Kale | 2.8 |
| Strawberry | 1.2 |
Limitations of this vertical farm LED estimate
This vertical farm LED estimate is intentionally simple. It assumes the stated PPFD is the average at the canopy and that the crop response to photons can be approximated with a single linear yield factor. In real facilities, results can differ because of:
- Light distribution and losses: racks rarely receive perfectly even PPFD; edge effects, reflections, aisle spill, and shadowing all reduce useful photons.
- Canopy development: as leaves expand, they self-shade and change how many photons are actually absorbed.
- Nonlinear crop response: photosynthesis can level off at high PPFD, and different cultivars respond differently to day length and intensity.
- Environment and management: CO2, temperature, VPD, nutrition, and irrigation can hold yield back even when the light dose is ample.
- Fresh vs. dry mass: the yield factor uses fresh mass for convenience, but water content varies a lot across crops and harvest stages.
- Whole-farm energy: the calculator only prices lighting electricity; HVAC, pumps, dehumidification, and controls are not included.
If you need tighter forecasts, use this tool to compare lighting recipes and bracket scenarios before you validate them with PPFD maps, crop trials, and energy monitoring.
Mini-game: Rack Tune — Hit the DLI Window
Because this calculator turns photons into both crop output and electricity cost, the optional mini-game below turns the same idea into a fast rack-balancing drill. It does not change your calculator result. Instead, it lets you practice the lighting tradeoff that vertical farms face every day: some racks are slipping below target, others are close to overlighting, and every photon burst consumes energy. The game lightly borrows your current PPFD, photoperiod, and efficacy settings so the run still feels connected to the scenario you are modeling above.
This optional mini-game reinforces the same idea as the calculator: crop performance depends on keeping photon delivery near the target while avoiding needless energy waste.