Primary Lighting in a Growth Chamber with Lettuce 330 Watt LED vs. 600 Watt HPS. Prepared for: LumiGrow Inc. By: Robert L. Starnes & Chris P.

Transcription

1 BTO Solutions, LLC 2320 Professional Drive Roseville CA office fax Primary Lighting in a Growth Chamber with Lettuce 330 Watt LED vs. 600 Watt HPS Prepared for: LumiGrow Inc. By: Robert L. Starnes & Chris P. Durand January 4, 2010

2 Primary Lighting in a Growth Chamber with Lettuce 330 Watt LED vs. 600 Watt HPS Principal Investigators: Objective: Materials: Methods: Robert L. Starnes, Chief Horticultural Consultant, BTO Solutions LLC, Roseville, CA (916) Christopher P. Durand, Senior Horticultural Consultant, BTO Solutions LLC, Roseville, CA (916) To compare growth of butter leaf lettuce in a growth chamber setting using high output LED lighting and the industry standard, High Pressure Sodium (HPS). Experimental Units- Butter Leaf Lettuce variety Live Gourmet 2 Treatments, 1 HPS lights and 1 LED lights 5 NFT troughs divided in the middle by a light barrier 15 plants per light treatment 1 main fertilized water reservoir for all treatments Media: 2 inch Q Plug, ihort Inc. Equipment- Custom NFT (Nutrient Film Technique) Hydroponics trough system; 5 troughs, 40 plant sites Lumigrow growth chamber, Treasure Island, San Francisco LumiGrow ES 330 Watt Xtrasun 600watt HPS ballast, Radiant 6 hoods Eye Hortilux 600 watt HPS bulb Custom Blend Fertilizer; GrowMore Pre-blend, Calcium Nitrate, Potassium Nitrate, Magnesium Sulfate, Monopotassium Phosphate Wat ermax This experiment was conducted inside a growth chamber at LumiGrow s Treasure Island testing facility. The NFT Hydroponic system was split in the middle by a light barrier with the HPS light on the left side and LED light on the right side. There were 2 treatments (LED and HPS), with 15 plants in the LED treatment and 16 plants in the HPS treatment. Plants (Figure 1) were kept in the growth chamber with an average temperature of 22 C ± 7.3 C (72 ± 12 F) and watered by

3 hydroponic NFT troughs with municipal water blended with fertilizer. The NFT water system ran at all times. All 5 troughs used water from one main fertilized water reservoir. The EC and ph of the fertilized water was maintained at 1.0 S and 5.8 respectively for the first week. The EC and ph of the fertilized water was then maintained at 1.5 S and 5.8 for the remaining cropping cycle. The photoperiod for the lighting was 16 hours per day (on at 6AM, off at 10PM) Figure 1: Butter Leaf Lettuce growing under HPS (left) and LED (right) in a greenhouse. Lettuce plants where planted in 2 Q plugs and placed into the NFT system under their respective treatments (Figure 2 and 3). The plants were grown for 32 days, the standard commercial cropping cycle. The data recorded for plant growth comparison was; length of roots per plant (Figures 4 and 5), weight (grams) per plant, and diameter (inches) per plant (Figure 6). Figure 2: Lettuce plants after being planted under 600-watt HPS lighting.

4 Figure 3: Lettuce plants after being planted under LED lighting. Figure 4: Lettuce plants showing roots from LumiGrow Treatment.

5 Figure 5: Lettuce plants showing roots from HPS Treatment. Figure 6: Lettuce plants being compared for diameter with HPS on the left and LED on the right.

6 Results:

7 Root Length: On average the plants from the Lumigrow group had longer root lengths than that of the HPS group inches compared to respectively. This difference was statistically insignificant (Chart 1). Chart 1: Shows the root lengths for HPS and LED treatments. Each error bar is constructed using 1 standard error from the mean. Weight of Plant: On average the plants from the HPS group were 10 grams heavier than those from the Lumigrow group. The difference was statistically insignificant (Chart 2). Chart 2: Shows the weights of plants grown under LED and HPS treatments. Each error bar is constructed using 1 standard error from the mean. Diameter (width) of Plants: On average the plants from the Lumigrow group produced plants 1.2 inches more compact regarding width than the HPS group. The difference was statistically significant (Chart 2). (p<.0020) (Chart 3). Chart 3: Represents the width of plants under LED and HPS treatments. Each error bar is constructed using 1 standard error from the mean.

8 Summary: The LED lighting treatment showed statistically significant differences as compared to the HPS lighting treatment for diameter of plants. The LumiGrow group stayed more tight and compact compared to the HPS group by an average diameter of 1.2 inches. There was no significant difference between LED and HPS light treatments for length of roots or weight of plants. ***Additional data analysis is available at the end of this document

9 Data Analysis Oneway Analysis of root length (inches) By Group Oneway Anova Summary of Fit Rsquare Adj Rsquare Root Mean Square Error Mean of Response Observations (or Sum Wgts) 31 t Test LUMIGROW-600W HPS Assuming equal variances Difference t Ratio Std Err Dif DF 29 Upper CL Dif Prob > t Lower CL Dif Prob > t * Confidence 0.95 Prob < t Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Prob > F Group Error C. Total

10 Means for Oneway Anova Level Number Mean Std Error Lower 95% Upper 95% 600W HPS LUMIGROW Std Error uses a pooled estimate of error variance Oneway Analysis of Weight (g) By Group Oneway Anova Summary of Fit Rsquare Adj Rsquare Root Mean Square Error Mean of Response Observations (or Sum Wgts) 31 t Test LUMIGROW-600W HPS Assuming equal variances Difference t Ratio Std Err Dif DF 29 Upper CL Dif Prob > t Lower CL Dif Prob > t Confidence 0.95 Prob < t Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Prob > F Group Error C. Total

11 Means for Oneway Anova Level Number Mean Std Error Lower 95% Upper 95% 600W HPS LUMIGROW Std Error uses a pooled estimate of error variance Oneway Analysis of width (inches) By Group Oneway Anova Summary of Fit Rsquare Adj Rsquare Root Mean Square Error Mean of Response Observations (or Sum Wgts) 31 t Test LUMIGROW-600W HPS Assuming equal variances Difference t Ratio Std Err Dif DF 29 Upper CL Dif Prob > t * Lower CL Dif Prob > t Confidence 0.95 Prob < t * Analysis of Variance Source DF Sum of Squares Mean Square F Ratio Prob > F Group * Error

12 Source DF Sum of Squares Mean Square F Ratio Prob > F C. Total Means for Oneway Anova Level Number Mean Std Error Lower 95% Upper 95% 600W HPS LUMIGROW Std Error uses a pooled estimate of error variance