Hydroponics and Vertical Farming: The Technical Guide to Understand, Grow, and Innovate

15. How to read the needs of the plant in hydroponics

Written by Tomato+ Team | Nov 28, 2025 1:47:50 PM

 

Understanding the signals to grow accurately and without errors

In hydroponics, plants communicate all the time-you just have to know how to interpret the signals. Whether it's a basil, a lettuce or a more demanding variety, every change in leaves, color, growth or roots offers valuable information about their status.
The goal is not to "guess," but to read plants in real time to intervene before problems occur.

In this article we look at how to do this easily, even if you are not an agronomist.

1. Leaf color: the first indicator to watch

Color tells immediately if the plant is in balance.

✔ Bright green

Sign of health: balanced nutrients, proper light, active roots.

⚠ Light green or yellowing.

Often indicates:

  • nitrogen, iron or magnesium deficiency

  • insufficient light

  • out-of-range pH stress

How to intervene: check EC, pH and photoperiod.

❌ Spots or burns.

Usually related to:

  • EC too high

  • light that is too bright or too close

  • major temperature fluctuations

2. Plant shape and posture: the plant "body language"

❥ Closed leaves, curling downward.

Excess water or root saturation.
In hydroponics it occurs when oxygen in the water is low or the solution temperature rises too high.

❥ Leaves pointing upward.

Typical sign of strong but positive light.
However, if they begin to stiffen, the light is too much.

❥ Slow growth and long internodes.

Means the plant is "seeking" light.
Increasing photoperiod intensity and stability brings back compactness.

3. Analyze the roots: the real engine of cultivation

In hydroponics, roots can be seen (huge advantage over soil).

✔ Crisp, white roots.

Perfect signal: optimal oxygenation and balanced nutrients.

⚠ Beige or slightly slimy roots.

Start of stress: nutrient solution temperature too high or insufficient circulation.

❌ Brown and strong-smelling roots.

Alarm: possible pathogen or severely insufficient oxygenation.

4. Growth: speed, symmetry and consistency

❥ Homogeneous growth

Indicates stable microclimate: air, temperature and light under control.

❥ Uneven or sloping growth.

Usually caused by uneven light source or direct air flows.

❥ Soft or sluggish tissues.

Often related to insufficient nutrients or too low EC.
In some cases also to incorrect photoperiod.

5. Microclimate: reading indirect signals.

Plants react quickly to:

  • too high humidity → mold risk, shiny, thin leaves

  • humidity too low → dehydration, dry margins

  • high temperature → large but weak leaves

  • low temperature → slow growth, dark color

In Tomato+ greenhouses this management is automated thanks to microclimate control and integrated sensors , but recognizing the symptoms remains useful for anyone.

6. Data: the most reliable way to read plants

In addition to visual signals, Tomato+ uses:

  • continuous telemetry

  • AI image recognition

  • Dynamic growth plans

  • Spectrum, height, pod status, and root sensors

This allows every plant signal to be transformed into data, automatically correcting light, irrigation, nutrients or photoperiod.

It is the transition from "by eye" cultivation to data-driven cultivation.

Conclusion

Reading the needs of the plant in hydroponics does not require complex skills: just observe the color, shape, growth and roots.
With smart systems like Tomato+, these signals become data that enable extremely precise, stable, and waste-free cultivation.

Thank you for reading this article. Keep following us to discover new content on hydroponics, vertical farming, and smart agriculture.
Tomato+ Team