Ask any grower: no two factors matter more than temperature and light when it comes to healthy, productive plants. They go hand in hand, and managing them together is what separates a good harvest from a great one.
In a recent blog, we talked about humidity (VPD), and how balancing temperature and humidity sets the stage for growth. Now let’s look at how temperature and light shape everything from plant structure to yield and quality.
Why light and temperature cannot be managed in isolation
Light gives your plants the energy they need for photosynthesis.Temperature regulates how well enzymes and metabolism keep up with that energy. The truth is, one doesn’t work without the other. High light levels only deliver results if the temperature is in the right range to let plants use that energy efficiently.
That’s why dialing in the balance is so critical. Get it right, and you’ll see faster growth, stronger morphology, and healthier plants at every stage.
Light levels across growth stages
Here’s a quick guide to typical commercial targets:
- Mother stock: 300-500 µmol/m²/s for 18 hours
- Propagation: 150–200 µmol/m²/s for 18 hours
- Vegetative phase: 300–700 µmol/m²/s for 18 hours
- Flowering phase: 800-1800 µmol/m²/s for 12 hours
Alongside these light levels, most growers adjust temperatures between 17°C (62.6 °F) and 30 °C (86 °F) depending on crop stage, airflow, humidity, CO₂, and fertigation.
What happens if they’re out of sync?
When temperature doesn’t match the light intensity, plants can’t keep up. Photosynthesis slows, stress builds, and photoinhibition sets in. The leaves may curl or bleach as a warning sign.
- Propagation & mother stock: Adjust light and temperature based on cultivar response.
- Vegetative phase: Low temperatures can push respiration above photosynthesis, leading to weak stems and stretch. Balanced spectrum and intensity help correct this.
- Flowering phase: A day/night temperature difference supports bud formation and terpene retention. Dropping temperatures just before harvest helps lock in bud quality.
The full picture
Light and temperature are central, but they’re only part of the story. CO₂, VPD and fertigation also play a role in keeping plants in the sweet spot. Managing them together maximizes yield, and boost quality, ensuring the product delivers its full value.
Want to know more, contact our Customer success team today.
