Post on 07-Mar-2020
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SOME EXPLANATION
• Consumption-What the plant actually uses• Waste-Run off, evaporation, percolation• Consumption is similar between outdoor and controlled environment with
HID Lighting• Waste is dramatically different between the two types of cultivation
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HOW IS WATER CONSUMED IN CANNABIS CULTIVATION?
• Clone– Minimal Water Use (Rooted cuttings in humidity domes)
• Vegetative Growth– Avg Peak Consumption 4 Gal/Day per Kw of Light– Lighting Density is 300-600 Watts per 25 Sq Ft– Or .048 Gal/Sq Ft-.096 Gal/Sq Ft
• Flowering Growth – Controlled Environment– Avg Peak Consumption 4 Gal/Day per Kw of Light– Lighting Density is 600-1000 Watts per 25 Sq Ft– Or .096 Gal/Sq Ft-.16 Gal/Sq Ft
• Flowering Growth - Outdoor Environment– Similar to High Density Controlled Environment– .12-.20 Gal/Sq Ft
Lighting Density Drives
Consumption/Sq Ft.
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HOW IS WATER WASTED IN CANNABIS CULTIVATION?
• Run off– Minimal in controlled environments– Significant in outdoor facilities (similar to traditional agriculture)
• Waste is a consideration• Pollutants is a bigger consideration (pesticides and fertilizers, both of which often have to
be used in greater density than in controlled environments)• Volume of run off varies and is difficult to measure with limited data (recent regulation)
• Evaporation– Loss of water through evaporation of source water– Loss of water through evaporation from soil
• Evaporation loss is minimized in hydroponic or aeroponic applications
• Disposal of unused irrigation water– Watering tanks have to be refreshed after harvest (different nutrient concentrations in early and
late stage growth)
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SOIL OR COCO (TRADITIONAL MEDIA)
• Nearly all outdoor facilities are in soil– Directly in ground or slightly raised– Raised “beds” limit run off and decrease waste– Waste through run off and evaporation from top layer of soil
• Many controlled environment facilities are in soil or coco– Cultivation in pots ranging from 1-10 gallons depending on veg time– Irrigation methods vary from automated drip to hand spray– Waste through percolation (through bottom of pot) and evaporation
from top layer of soil
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AEROPONICS
• Method where plants are suspended in chambers and roots are periodically sprayed with nutrient rich mist– Little to no evaporation loss– No loss due to run off– Waste is limited to emptying of
chambers (ideally once per harvest but could be as often as every two weeks)
– Irrigation is typically automated– More expensive and less forgiving
than soil or coco method
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HYDROPONICS
• Roots are drenched in nutrient rich solution periodically
– Ebb and Flow or Flood and Drain– Usually on a timer or control system– Limited waste through evaporation– Could be significant waste through run
off depending on management practices
– Can be done inexpensively– Less forgiving than soil– Cultivators indicate that flavor is
sometimes compromised by this method
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DEEP WATER CULTURE
• Hydroponics method where roots are constantly submerged in nutrient and oxygen rich solution– Little to no evaporation loss– Little to no run off– Higher than typical consumption volume
is possible (constant access to water)– Only waste is system clean out at end of
harvest
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PREFILTERING IRRIGATION WATER
• Reverse Osmosis– Method of filtration where particulate gathers in
one chamber and clean water gathers in other chamber
– Provides lowest PPM possible as starting point so cultivators know exactly what they’re feeding
– Produces waste of 0.5-5 gallons dirty water to 1 gallon clean water depending on cleanliness of supply
– Variances in what the plant consumes and other environmental stressors will result in variances in CBD/THC profiles
• Variances in consumer experience
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CONDENSATE RECLAMATION
• Plants don’t consume water-they borrow it– All irrigation water is eventually transpired back out into the
space– Properly designed HVAC systems can reclaim and treat
condensate water for reuse• Oxygenate• PH• Sterilize• Filter
– Possible to reclaim 100% of irrigation water through this method
– When RO is in use, reclaiming 1 gallon of irrigation water can result in savings of up to 6 gallons from municipal supply or well
– Only possible in controlled environments
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OTHER WAYS TO CONSERVE
• Outoors– Place plants in slightly raised beds to reduce run off– Consider mulch or other covering to minimize evaporation
• Indoors– Use most efficient RO filter available to minimize waste– Use automated irrigation methods to reduce waste and minimize overwatering– Cover all reservoirs (and pots in soil and coco applications) to minimize
evaporation– After nutrient solution is “spent,” run it through RO to capture as much clean
water as possible and minimize waste