Cannabis Fertility Program - Irrigated

The plan below is a general outline of nutritional needs and applications for a successful and healthy crop of cannabis. Final plans, with specific requirements are always established in consultation with a Bio Minerals Technologies representative based on the specific needs of the grower, field, and crop.

The first step in any good program implementation is to have a current soil report. This report determines the soil minerals available, which are then compared to the nutrient demands of the crop in order to plan adequate supplemental nutrition. Applied nutrients should always be in the correct form and time frame so they are soluble and plant available when the plant demand occurs.

Tissue tests should be taken every 7-10 days and the nutrient applications adjusted accordingly.

Macro Nutrients

Total lbs needed/acre Nitrogen (N) Phosphorus (P) Potassium (K) Sulfur (S)
Average (minimum) 150 lbs 67 lbs 120 lbs 30 lbs
Large (maximum) 225 lbs 100 lbs 180 lbs 45 lbs

Nitrogen Applications

Apply up to, but not more than, 10 lbs of Nitrogen in-furrow, with the seed.

  • Use up to 6 oz/acre/year of Molybdenum 3% in multiple applications of no more than 2 oz each. Molybdenum can be applied with liquid N in the soils, or it can be applied as a foliar spray with trace elements (do not apply N as a foliar on the plant). Molybdenum helps the plant to more efficiently utilize the available Nitrogen.
  • The majority of the Nitrogen needed should be applied while in vegetation (pre-flower)
  • In tissue tests, keep N and K levels as close to each other as possible. This parity will increase the quality of the plants and help prevent disease.

Phosphorus Applications

The absolute best method for Phosphorus applications is with liquid fertilizer (3-18-18, 9-24-6, 10-34-0, 11-37-0), stabilized with Bio Release. Use one gallon of Bio Release with 12 gallons of liquid P. Stabilizing the liquid phosphate gives the plant that early energy from available P which produces bio-mass. Liquid P with Bio Release can be applied at planting or injected through the drip line or via irrigation.

Potassium Applications

The majority of the Potassium (K) (at least 80 percent) will be pulled into the plant prior to flower set. You can use liquid K (KTS) which can be applied with the liquid P and Bio Release.

Sulfur Applications

The plants will only use about 10-20 percent of the required Sulfur (S) prior to flowering. The remaining S is used during flowering and reproduction phases to maturity. Be sure to time and apply forms of Sulfur that will be available when the plant needs it.

Foliar Applications and Options

Foliars can be done bi-weekly (every 2 weeks). The basic foliar is as follows (per acre):

  • 16 oz Bio Release
  • 32 oz Foliar Micro Boost
  • 1 oz Molybdenum 3% (no more than 6 oz per growing season)


O2-YS should be added to the foliar mix at a rate of 16 oz/ac at least every four weeks. If disease pressure is high, it can be used every two weeks.

Note: When mixing O2-YS into your foliar, the pH of the mixed liquid must be at 5 or less before adding the O2-YS. The best method to lower your foliar pH is to mix in dry acetic acid (1/2 – 1 tsp per gallon).


Bulk-R is an excellent option for increasing bud size. Apply 1 gallon/acre 30-40 days prior to harvest. It can be mixed in with the regular foliar for a combined application.

Microbial Mineral Tea

Bio Minerals Technologies Microbial Mineral Tea is an excellent option to reinforce and build beneficial microbial populations in the soil and root zones of the plants. The enhanced biological populations will strengthen and feed the plants and help to control pathogenic populations, thus reducing disease and infections. It is easily applied via drip line or irrigation at a rate of 10-15 gallons per acre.

Since medical marijuana plants are tested for microorganisms on the leaves, it is generally best to avoid applying tea to the foliage due to limits on vegetation microbial counts (the tests don’t distinguish between good microbes and bad microbes).

With hemp, however, it is very beneficial to apply Microbial Mineral Tea as a foliar every 2-4 weeks at a rate of 10-15 gallons per acre.

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