• AgSil 21, 55 gallon potassium silicate fertilizer
  • AgSil 21 soluble silicon fertilizer.
  • Description
  • Specifications
  • Application Rates

AgSil® 21 Aqueous Potassium Silicate Fertilizer – 55 Gallon

AgSil 21 is a fully soluble liquid potassium silicate providing a 100% plant-available source of silicon and potassium. With a low salt index, AgSil 21 is extremely safe for all crops including sensitive varieties. Applied via soil drench or foliar spray, it activates the plant’s natural defenses and improves tolerance to a wide range of biotic and abiotic stresses.

Guaranteed Analysis

  • Silica (SiO₂): 26.5%
  • Potassium (K₂O): 12.7%
  • Derived from potassium silicate

Key Features

  • 100% plant-available silicon and potassium in liquid form
  • Low salt index — safe for sensitive crops
  • Activates plant immune response against fungal, bacterial, nematode, and viral pressure
  • Improves tolerance to drought, heat, frost, salinity, and mineral toxicity
  • Compatible with most spray tank mixes
  • Raises solution pH — add to water before other nutrients

Ideal Applications

  • Hydroponic nutrient solutions
  • Fertigation: drip, micro-jet, sprinklers
  • Foliar spray programs
  • High-stress crop environments

Packaging

  • 55 gallon drum
  • Ground shipping only

Guaranteed Analysis:
Silica (SiO2)…………. 26.5%
Potassium (K2O)........12.7%

Derived from Potassium Silicate
Caution: Always add AgSil 21 first to the spray tank water. A jar test is recommended to test compatibility when new or unfamiliar tank mix combinations are used.

GENERAL USE RECOMMENDATIONS
GROUND APPLICATIONS: Apply 1.5 to 3 pints per acre in sufficient water for thorough spray coverage.
AERIAL APPLICATIONS: Apply 1.5 to 3 pints per acre in minimum of 5 gallons of water per acre.
IRRIGATION (Sprinkler, Drip, Pivot): Apply 3 to 6 pints per acre through irrigation system.
Application and Rate Instructions:
TURFGRASS and SOD: Apply 1.5 to 2.25 fluid ounces per 1000 sq. ft. every 7 to 14 days. If turf is under
stress application interval can be increased to achieve desired result.
ORNAMENTALS, NURSERY, GREENHOUSE: Apply 1.5 to 3 pints per 100 gallons of water.
HYDROPONICS SOLUTIONS: Add 3.5 to 7 fluid ounces per 100 gal of water. Resulting mixture
should then be buffered to the optimum pH for nutrient solution and specific crop feeding. 
VEGETABLES: Apply 1.5 to 3 pints per acre. For best results apply a minimum of 3 applications.
POTATO and other TUBER CROPS: Apply 1.5 to 3 pints per acre from planting to defoliation for plant
health and to aid in skin set and sizing.
VINES, TREE NUTS, FRUIT TREES: Apply 1.5 to 6 pints per acre. First application at pre-bloom. For best
results apply a minimum of 3 applications.
BUSHBERRY AND CANEBERRY: Apply 1.5 to 3 pints per acre. First application at pre-bloom.
ROW CROPS: Apply 1.5 to 3 pints per acre. Higher rates or more frequent applications may be required to
correct deficiencies.
SUGARCANE and RICE: Apply 3 to 6 pints per acre. For best results apply a minimum of 2-3 applications.
Apply at 28 to 42 day intervals. Higher rates or more frequent applications may be required to correct
deficiencies.
SOIL APPLICATIONS: May be made pre-plant, side dress or in irrigation at 3 to 6 pints per acre. 

AgSil 21 Potassium Silicate 55 Gallon

AgSil 21 Potassium Silicate 55 Gallon

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What Makes Us Different

At the leading edge of the market, Custom Hydro stands out by providing the growing industry with fertilizers that are not only of premium quality but also feature innovative
solutions tailored for the unique needs of hydroponic and organic farming practices.

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  • Highest Purity

    Never Compromise on the Quality of Inputs.

  • Crop Specific

    Customized Fertilizer for your Favorite Crops.