A Validation Study of the House and Garden Line of Dry and Liquid Nutrients

A Comparison of Fertilizer Regimes in Commercial Cannabis sativa Production:
A Validation Study of the House and Garden Line of Dry and Liquid Nutrients

Dr. Robert Flannery
Dr. Robb Farms, Desert Hot Springs , CA


Cannabis cultivation, like any other form of agriculture, requires growers to keep a keen eye on the nutrition of their crops. Due to the legal landscape of Cannabis cultivation, research efforts into the behavior and needs of cannabis as a crop have been curtailed until recently. Traditionally, cannabis cultivators did not consult with researchers or botanists as the science was either unavailable or threadbare when provided. 

The underground nature of cannabis cultivation has woven the practice into potentially inefficient and sometimes contradictory territory to obtain the best product possible. Only recently has the changing legal landscape enabled extensive academic study into the crop and its nutritional needs and behaviors. 

Materials and Methods

  • 27 randomly selected clones of Cannabis sativa ‘Soap’ were chosen for the study
  • Temperature, Humidity, Light, and Water were monitored for consistency
  • Nutrients (Control, H&G Liquid, and H&G Dry) were held as the only variable
  • Grow: 18hr light, 6hr Dark. Bloom: 12hr light, 12hr dark
  • All plants harvested after 63 days of flower
  • Plants were cut and weighed at several points, including wet weight, dry pre-cure weight, post cure weight, and final product weights
  • Final product weights recorded as trim, smalls, and flower

Trial Results 


increase in bud site
accumulation during
the growing phase.


more final flower
by weight.


flower production
on identically-sized plants.

A significant difference was found between the two nutrient regimens. Plants receiving the H&G nutrient regimen were found to accumulate 39% more bud sites than the control group.
Differences in plant heights and growth rate were not found to be statistically significant. Indicating that the plants in the H&G groups formed more bud sites at a similar rate of growth and size.
After drying, curing, and trimming, the recorded final weights were compared. Plant Components were broken down into trim, smalls, and final flower. the plants in the H&G group were found to have a final flower mass 32% higher than the control group, with similar biomass weights. 


  • The H&G groups of trial specimens exhibited a 39% increase in bud site accumulation during the growing phase when compared to the control.
  • The H&G groups produced 32% more final flower by weight than the control group.

The difference in yield is rather significant, being almost a full third more finished product by weight when compared to the control group. It is believed that the accelerated accumulation of bud sites that was observed in the H&G group during the growing phase lead directly to the increased yield of the final crop. Interestingly, the discarded biomass proportions were similar across all 3 groups. This indicates that the plants using the H&G regimen of nutrients and additives had produced more flowers on an identically sized plant. 


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