Ugrow Organic: Hormones & Temperature

Ugrow are UK distributors for Metrop products. Information on this page is copyright Metrop 2004.

Light / Dark / Hormones

The proportion between light and dark (day and night) we call the photo period. Blooming starts when the days get shorter, growing and blooming of the plant is influenced by the hormone Fytochrome. The plant makes this hormone day and night but production tapers off during the daylight cycle.

The hormone will gain the upper hand when the plant is in the dark for 12 hours in a 24 hour period and will start the blooming of the plant. A small amount of light in this dark period can interrupt the blooming process or even completely stop it.

That is why it is very important never to enter a grow room during the night cycle, not even with a flash light. If the light is set for 18 hours, the hormone will never gain the upper hand and the plant will remain in a vegetative stage and will only keep on growing.

Light is also important for producing energy.

6H2O + 6CO2 ----------> C6H12O6+ 6O2

Easier said:
Six molecules of water + six molecules of carbon dioxide
Produce:
one molecule of sugar + six molecules of oxygen
Or
Water + carbon-light-> energy

The more light, the more energy a plant can make provided that there is enough water and CO2.

A trick some growers use is, in the last 2 weeks of the blooming period to up the light from 12 to 14 hours. The plant has enough hormones in it, to keep on blooming but gets an extra 2 hours of light each day to make more energy (and 2 hours less dark to use the energy).

Temperature / Energy

Energy/Temperature Graph:
Assimilation-Breathing-Growth

Temperature is an important yield determining factor. If the temperature is not right, the plant will grow less or not at all.

Research and experience teaches us that the best temperature around the leaf is 24-26 degrees Celsius for all vegetation, to achieve maximum growth and bloom throughout the plants day and night cycle.

During the day the plant makes energy to grow (assimilation) and at night, the plant uses that energy to grow.

The art of growing is to make sure that during the day the plant makes as much energy as possible and that at night uses the least amount of energy possible.

We can stimulate this during the day by adding more CO2 and more light, and stimulate the evaporation under the leaf, in mature plants through air circulation.