Gaia Green Oyster Shell Flour

$17.95 $15.25

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GAIA GREEN Oyster Shell Flour is a renewable alternative to mined limestone with a comparable capacity for ameliorating soil acidity. A single application can improve soil properties for several years. GAIA GREEN Oyster Shell Flour is an excellent choice for all gardens where increased soil pH is desired.


GAIA GREEN Oyster Shell Flour is approved for use in organic agriculture by Ecocert Canada (in compliance with Canada’s Organic Production Systems General Principles & Management Standards and Permitted Substances Lists (CAN/CGSB 32.310-2015 and CAN/CGSB 32.311-2015)).


  • An excellent source of slow release calcium.

  • Equivalent to limestone for ameliorating soil acidity.

  • Renewable resource.

Guaranteed Minimum Analysis

Calcium (Ca)....................................36.0%

Neutralizing value (CaCO3)..............96.0%

Passes 100 mesh TYLER Screen.......30%

Derived From

Oyster Shell Flour.

Directions for Use

Gardens and Landscapes: For reducing soil acidity, broadcast and incorporate 0.5 - 6.75 kg per 10 m2 (1 - 13.8 lbs per 100 ft2). For equal pH adjustment sandy soils require a lower rate compared to clay soils and those high in organic matter. Consult an agronomist to determine appropriate rates for your garden soil.

Field: Consult an agronomist to determine an appropriate application rate. Typical rates are between 560 to 6700 kg per ha (500 to 6000 lb per acre).

Top-dressing hanging baskets, potted plants, and planter boxes: Mix in 15 ml per 4 L (1 tbsp per gallon) of soil or growing media. Apply monthly or as desired. Effects of this product on soil pH may take in excess of 1 year to be fully realized.