Solution Maintenance

Marijuana Horticulture

by Jorge Cervantes

Plants use so much water that nutrient solutions need to be replenished regularly. Water is used at a much faster rate than nutrients. Casually topping off a reservoir with pH-balanced water will keep the solution relatively balanced for a week or two. Some growers top off the nutrient solution with 500-700 ppm-strength nutrient solution every two to three days. Never let the nutrient solution go for more than fur weeks before draining it and adding fresh solution. Smart growers leach the entire system with weak nutrient solution for an hour or more between changing the reservoir. Wipe down the entire system with the solution.

Do not flush with plain water. Flushing with mild (quarter-strength) nutrient solution will actually remove more excess fertilizer than plain water. Check EC of reservoir, growing medium, and runoff nutrient solution at the same time every day.

Use an electric EC pen to monitor the level of dissolved solids in the solution. Occasionally you will need to add more fertilizer concentrate to maintain the EC level in the reservoir during the topping off times. Keep the reservoir full at all times. The smaller the reservoir, the more rapid the depletion and the more critical it is to keep it full. Smaller reservoirs should be refilled daily.