Microclimate is one of the pillars of indoor growing: it determines health, growth rate, final yield and plant stability.
Managing it properly means controlling temperature, humidity, air movement and turnover, maintaining repeatable conditions compatible with the physiological needs of the plants.
A plant can have the best LEDs, the perfect nutrient solution, and flawless irrigation cycles-if the microclimate is not stable, the crop will never reach its potential.
It directly influences:
Temperature and humidity determine vapor pressure (VPD): if it is out of whack, plants suffer stress and slow down.
Microclimate affects available CO₂, leaf temperature, and the plant's ability to maintain efficient photosynthesis.
Areas with stagnant air create micro-environments favorable to mold, Botrytis and pathogens.
Without a stable microclimate, it is impossible to achieve repeatable results, especially in multilevel systems.
Plants tolerate small deviations, but cannot tolerate rapid swings.
Indicative ranges:
Vegetative: 20-24°C
Productive: 22-26°C
Night: 2-4°C lower
Common mistakes:
LEDs heating the top of the plant too much
Cold air directed at leaves
Oversized HV/AC creating oscillations
Optimal ranges:
Germination: 70-80%
Vegetative: 55-70%
Maturation: 50-65%
Need stable, non-oscillating control: dehumidifiers, distributed sensors, fine-tuning logic.
Vapor Pressure Deficit allows you to tell if the plant is really working efficiently.
Benefits of VPD control:
Reduced stresses
Faster growth
Improved nutrient uptake
Improved final quality
Tools such as AI Tomato+ software allow you to monitor trends, automate corrections, and keep VPD always in the optimal zone.
Air movement is the most underestimated component, but it is the one that determines the real uniformity of the environment.
Eliminate stagnant areas
Avoid pockets of heat under LEDs
Uniform temperature and humidity
Improve leaf gas exchange
Support VPD management
Conventional LEDs generate a lot of direct downward heat, creating hot spots above the canopy and forcing corrective ventilations.
Liquid-cooled Tomato+ LEDs solve the problem at the root:
Zero heat pockets above the plants: heat does not build up above the canopy because it is extracted by the cooling circuit.
Uniform microclimate between all levels: water stabilizes module temperatures and helps thermally homogenize the entire multilayer system.
Reduced need for corrective airflow: better sized, more stable and more efficient ventilation.
Improved safety and consistent performance: no local overheating or unexpected variations between floors.
This makes environmental control easier, more stable, and much more predictable in growth cycles.
Fans that create a steady but smooth flow (0.2-0.4 m/s), with no direct wind on leaves.
Serves to stabilize CO₂, remove waste heat, and control humidity.
Essential to avoid differences between layers.
Liquid-cooled Tomato+ LEDs facilitate natural thermal homogeneity between tiers, simplifying vertical airflow management.
In vertical systems need:
Multiple sensors for each level
Separate control for LEDs and grow chambers
Predictive algorithms to prevent oscillations
Airflow calibrated by floor and not generically to the environment
Continuous telemetry and AI are crucial to ensure production uniformity and repeatability.
Using only one sensor for the entire plant
Not considering the actual heat produced by LEDs
Direct airflow to leaves
Insufficient air exchange
No trend analysis, only "on/off" control
Ignoring VPD
Failure to differentiate between levels in multilayer plants
Microclimate is not controlled, it is designed.
You need a combination of: sensors, smart airflow, advanced thermal management, and predictive algorithms.
The goal is not to maintain fixed numbers, but to create stable, reproducible and optimized conditions for stronger, faster and better performing plants.
Thank you for reading this article. Keep following us to discover new content on hydroponics, vertical farming, and smart agriculture.
Tomato+ Team