Environmental Setpoints Guide for Indoor Farming
Reference optimal temperature, humidity, CO₂, VPD, EC, pH, DLI, and dissolved oxygen setpoints for 10 indoor farming crops by growth stage. Includes low, target, and high thresholds with grower notes.
What Are Environmental Setpoints?
Environmental setpoints are the target values for the controllable parameters in an indoor growing environment: air temperature (day and night), relative humidity, CO₂ concentration, VPD, nutrient EC, pH, DLI, and dissolved oxygen. Each crop species has an optimal range for each parameter at each growth stage. Setting these correctly is the foundation of indoor farming — they determine growth rate, yield, quality, shelf life, and energy consumption. The day/night temperature differential (DIF) is particularly important for controlling plant morphology and triggering developmental responses.
How to Use This Calculator
- 1 Select your crop from the 10 supported species. The calculator shows all environmental parameters for that crop.
- 2 Choose a growth stage. Each stage has different optimal ranges reflecting the plant’s changing needs from propagation through harvest.
- 3 Review the low, target, and high thresholds for each parameter. Program these as setpoints in your environmental controller.
- 4 Read the grower notes for stage-specific tips on temperature DIF, CO₂ supplementation timing, and common pitfalls.
Key Setpoints by Crop (Grow-out / Vegetative Stage)
| Crop | Day Temp (°F) | Night Temp (°F) | RH (%) | CO₂ (ppm) | EC (mS/cm) | DLI |
|---|---|---|---|---|---|---|
| Butterhead | 72 | 64 | 65 | 1,200 | 1.2 | 16 |
| Romaine | 72 | 64 | 65 | 1,200 | 1.4 | 17 |
| Basil | 80 | 70 | 60 | 1,400 | 1.4 | 20 |
| Arugula | 65 | 60 | 65 | 1,000 | 1.2 | 15 |
| Kale | 68 | 62 | 60 | 1,200 | 1.6 | 18 |
| Microgreens | 72 | 68 | 70 | 800 | 0.6 | 12 |
| Strawberry | 72 | 64 | 65 | 1,000 | 1.5 | 22 |
| Tomato | 80 | 68 | 60 | 1,200 | 2.2 | 25 |
| Cucumber | 78 | 68 | 60 | 1,000 | 2.0 | 22 |
| Pepper | 80 | 68 | 55 | 1,200 | 2.2 | 25 |
Frequently Asked Questions
What is DIF in indoor farming?
DIF is the difference between day and night temperature. A positive DIF (warmer days, cooler nights) promotes stem elongation and is standard for most crops. A 6–8°F drop at night encourages compact growth in lettuce and triggers developmental signals. Basil requires a minimum night temperature of 65°F to avoid chilling injury.
When should I supplement CO₂?
CO₂ supplementation is most effective when light levels are high enough for plants to use the extra carbon. Supplement only during the photoperiod (lights-on), and only when VPD and temperature are in their optimal ranges. Most leafy greens benefit from 1,000–1,500 ppm; ambient air is ~420 ppm.
How does water temperature affect root health?
Nutrient solution temperature affects dissolved oxygen levels and root disease risk. Most crops prefer 64–72°F water temperature. Above 75°F, dissolved oxygen drops and pythium risk increases significantly. Below 60°F, nutrient uptake slows. Chilling systems are essential in warm climates.
What dissolved oxygen level do roots need?
Healthy hydroponic roots need at least 5 ppm dissolved oxygen (DO), with 8–10 ppm being optimal. DWC and NFT systems should target 6+ ppm. Aeroponics inherently provides high DO through air exposure. Low DO leads to anaerobic conditions, root browning, and pythium infection.
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