Proof of Concept: SANlight EVO-Series Test

Methodology

The entire experiment took place in a single room, in one of our plant laboratories. This room is air-conditioned to maintain and control constant climatic conditions (humidity and temperature). An atmospheric CO2 level of 400-450ppm was maintained.

The temperature was maintained at an average of 26°C during the day and lowered to an average of 23°C during the night. Room humidity was also kept constant between 60-70% during vegetative growth and between 50-60% during the generative phase (flowering) of the plants.

In order to eliminate interfering stray light between individual experiments, grow tents, “Homebox Ambient R240+” were used for the experiment. The grow chambers have a dimension of 2.4×1.2×2.2m (LxWxH), resulting in 2.88m² floor space and 6.3m³ volume. Nutrients were supplied by a central watering system via drip irrigation. This ensured that all plants received the same nutrients.

In order to pursue the goals of the experiment, several cultivation chambers were exposed to different light intensities. Therefore, we decided to use the two EVO models that were suitable for this purpose. EVO 4-120 and EVO 5-120, each designed for areas with a depth of 120cm. Grow chamber 1 was equipped with four EVO 5-120, grow chambers 2 and 3 were equipped with EVO 4-120. Chamber 3, which was equipped with four EVO 4-120, was to be operated at a maximum of 80% of the rated power.

The EVO luminaires have the following spectral color distribution
– Blue 14%; – Green 37%; – Red 45%; – Far Red 4%

Light intensity vs. height growth and cell strength.

The plants were distributed into the individual chambers with an average height of 15cm. Height growth in the vegetative stages was similar for all plants. As expected, after the time change from 18 to 12 hours of exposure time, the plants started with more elongation of the internodes due to the lowered DLI, which stabilized within two weeks.

The seed plants reached an average height of 87cm. After the elongation phase due to flower initiation, little height growth occurred in most plants. Plants under the high intensity of EVO 5-120 remained on average 5% lower and stockier than plants in chambers 2 and 3.

It is worth mentioning the evidence that cell strength increased at higher intensities. Thus, the stems of the plants under the highest intensities were noticeably stronger than the stems of plants under the lower light intensities.

Documentation Day 7 - 14

Exposure time: 18 hours daily

Ø PPFDe 400µmol/m²/s
DLI 25,92mol/m²/d

temperature: 26°C room humidity: 70%

The light intensity in the tents was set to 300µmol/m²/s at the beginning. From the 8th day, the PPFDe was increased to 400µmol/m²/s.
Plants recovered from transplanting from 1 L to 7 L pots and started new growth.
Root growth has started. The root system is now starting to supply the plants with sufficient nutrients.
Due to the organic pre-fertilization of the substrate, slight signs of overfertilization appear on a few plants.
The plants get a daily amount of water of 500ml per day and plant. Watering is done with a light fertilizer solution of 0.9 EC at a pH of 6.3.

Documentation day 15 - 21

Exposure time: 18 hours daily

Ø PPFDe 400µmol/m²/s
DLI 25,92mol/m²/d

Temperature: 26°C Room humidity: 70%

Light intensity is still set to 400µmol/m²/s.
The plants show strong compact growth.
The plants get a daily water amount of 700ml per day and plant.
Watering is done with a light fertilizer solution of 1.2 EC at a pH of 6.2.

Documentation day 22 to 28, 1st week of flowering

Exposure time: 12 hours daily

Ø PPFDe 500µmol/m²/s
DLI 21,6mol/m²/s

Temperature: 26°C Room humidity: 70%

Light intensity was slightly increased from 400µmol/m²/s to 500µmol/m²/s.
The plants are now starting to develop more lateral shoots.
The morphological development is as expected.
The leaves have a strong structure and healthy leaf color.
The plants receive a daily water amount of 800ml per day per plant.
Watering is done with a light fertilizer solution of 1.2 EC at a pH of 6.2.

Documentation day 29 - 35, 2nd week of flowering

Exposure time: 12 hours daily

Ø PPFDe 500µmol/m²/s
DLI 21,6mol/m²/s

Temperature: 26°C Room humidity: 65%.

The light intensity was increased from 500µmol/m²/s to the maximum power of the lights.
Tent No. 1, EVO 5-120 ~1.100µmol/m²/s. Tent No. 2, EVO 4-120 ~850µmol/m²/s.
Tent No. 3, EVO 4-120 to 80% ~650µmol/m²/s.
The plants are now in a strong elongation phase and the nodal spacing is starting to lengthen noticeably. Growth is still very satisfactory.
The plants are developing vigorously and no longer show signs of over-fertilization.
The plants get a daily water amount of 900ml per day and plant.
Watered with a light fertilizer solution of 1.4 EC at a pH of 6.2.

Documentation day 51 - 57, 5th flower week

Exposure time: 12 hours per day

Ø PPFDe
Tent 1 1.100µmol/m²/s
Tent 2 880µmol/m²/s
Tent 3 700µmol/m²/s

DLI
Tent 1 47.52mol/m²/d
Tent 2 38.01mol/m²/d
Tent 3 30,24mol/m²/d

Temperature: 26°C Room humidity: 60%

The plants tolerate all administered light intensities very well, even though bleaching starts in some plants especially under the high intensities.
The stretching phase is over and the plants have now reached the main flowering phase.
The plants have reached their final height and the volume of the flowers is increasing.
The morphological development of the plants is very good.
The plants get a daily amount of water of 1.300ml per day per plant.
Watering is done with a light fertilizer solution of 1.5 EC at a pH of 6.0.

Documentation day 58 - 64. 6th week of flowering

Exposure time: 12 hours daily

Ø PPFDe
Tent 1 1.100µmol/m²/s
Tent 2 880µmol/m²/s
Tent 3 700µmol/m²/s

DLI
Tent 1 47.52mol/m²/d
Tent 2 38.01mol/m²/d
Tent 3 30,24mol/m²/d

Temperature: 26°C Room humidity: 55%.

Budding continues to progress.
Bleaching also progresses as flower growth increases.
The flowers are noticeably increasing in mass.
The plants get a daily water amount of 1.300ml per plant.
Watering is an EC value of 1.7 with a pH value of 5.8

Documentation day 78 - 84. 9th flowering week

Exposure time: 12 hours per day

Ø PPFDe
Tent 1 1.100µmol/m²/s
Tent 2 880µmol/m²/s
Tent 3 700µmol/m²/s

DLI
Tent 1 47.52mol/m²/d
Tent 2 38.01mol/m²/d
Tent 3 30,24mol/m²/d

Temperature: 26°C Room humidity: 55%

The ripening phase of the plants has started and the developed flowers begin to bulk up.
Bleaching no longer occurs on new plants. The fragrance in the grow room becomes more intense.
The plants receive a daily water amount of 900ml.
Fertilization has reached its peak and the plants receive an EC of 1.7 with a pH of 5.9 for this last week.

Documentation day 92 - 98. 11th flowering week

Exposure time: 12 hours per day

Ø PPFDe
Tent 1 1.100µmol/m²/s
Tent 2 880µmol/m²/s
Tent 3 700µmol/m²/s

DLI
Tent 1 47.52mol/m²/d
Tent 2 38.01mol/m²/d
Tent 3 30,24mol/m²/d

Temperature: 26°C Room humidity: 45%

This is the last flowering week for the plants and the room smells very intense.
Flower development is very good down to the lower parts of the plants
The ripening stage is well advanced and the plants are ready for harvest.
By skipping fertilization, the plants have noticeably lost color and the leaves have turned autumnal.
The plants are getting very little water at 500ml per day per plant and are being forced to dry out.
The EC value this week is 0.4 and the pH 5.8.

Harvest

The day before harvest, the plants were no longer watered, in order to deprive the flowers of as much water as possible.
On the day of harvest, all large fan leaves were removed from the plants still standing.
After removing the fan leaves, the plants were cut at pot height and the flowers were separated from the stem.
Subsequently, the flowers were freed from their petals and the flowers were hung to dry.

Harvest

After successful flowering phase, the harvest of the hemp plants took place. The plants were first cut off whole and dried. Subsequently, the flowers were separated from the plant. The dry flowers were then trimmed by machine. Subsequently, the flowers were then finally dried at 20°C and 55% humidity. The flowers were sorted according to size (large and small flowers), and weighed.

Results

With the SANlight EVO series, exposure intensities >1.000µmol/m²/s lead to an increase in yield per area, but reduce the yield/performance ratio by up to 26%.

Further, this trial demonstrates the superior performance of our EVO-series. Even when operating the lights at only 80% of their power, yields well above 500g/m² are achievable and more than 2g of flower mass can be produced per watt.

From an economic point of view, the use of the EVO 4-120 is absolutely recommendable, and a reasonable compromise between performance and economy.

To confirm the results, this trial will be repeated and published again on our webpage in a few weeks.