Omya Top Flow Ca

High efficiency calcium carbonate slurry for use in irrigation systems and liquid fertilizer applicators.

Why should I use Omya Top Flow Ca? 

Top Flow® Ca is a fast-acting calcium carbonate slurry that provides essential calcium nutrition to the crop and quickly adjusts soil pH. It is optimized for application through irrigation systems and sprayers.

The benefits of Omya Top Flow Ca 

  • Quickly adjusts soil pH
  • Provides essential calcium nutrition to increase fruit and produce quality, grow stronger plants, reduce blossom end rot and increase packability of the crop 
  • Ultrafine particles release available calcium quickly to the plant 
  • Stable suspension for easy handling and spraying 
  • Liquid formulation provides a dust free application 
  • Formulation optimized for easy application through spray equipment, liquid fertilizer applicators, drip and overhead irrigation systems. 

Not all products are registered for use in all markets. Check with your local Omya representative for more information.

"In the past, I tried to raise soil pH with no success but after an application of Top Flow Ca, not only did the pH go up by a full point, but I got a call from the farm manager telling me how this was the first time in years that he saw the trees look this good. "


-Chris Whipple, PCA for Gar Bennett, California, USA

What is Omya Top Flow Ca? 

Top Flow Ca is a soil conditioner and source of calcium nutrition that can be applied through all irrigation systems and liquid applicators. It is a slurry made from fine particles of calcium carbonate. Top Flow Ca flows smoothly through micro-irrigation (drip-irrigation) systems, overhead sprinklers and liquid fertilizer applicators without clogging or causing blockages.


How does Omya Top Flow Ca correct soil pH quickly?  

The build-up of hydrogen ions on the clay humic complex can be corrected by applying calcium carbonate.  Top Flow is made from ultra-fine particles of calcium carbonate in suspension. The ultrafine particles have a high surface area, reacting quickly with the acidity in the soil, improving it within just a few weeks so your crops get the benefit within the same season. At neutral pH, 100% of applied fertilizers become available to the crop, improving nutrient use efficiency.

NPK availabliity graph

Why is calcium nutrition important for crops? 

Calcium is an essential nutrient for all crops. It is required for the formation of cells, strengthening the cell wall and providing structural rigidity to the cell. Calcium is immobile in the plant, so it is essential to provide a continuous supply, readily available to the plant throughout the growing cycle. Omya Top Flow Ca contains 25% calcium, providing a readily available source of this essential nutrient to the plant.


  • Calcium maintains the structural integrity of cell wall and cell membrane
  • Calcium helps preserve the cation-anion balance, counteracting inorganic and organic anions
  • Calcium improves the quality and storability of the fruit
  • Calcium promotes cell expansion in root and pollen tube
functions of calcium illustration

Talk to an expert

For information or advice, please contact us now.

How easy is Omya Top Flow Ca to use?  

Top Flow Ca can be applied using traditional spray equipment, or through drip or overhead irrigation systems. Application rates depend on soil type, crop and agronomic objectives. For specific advice to suit your circumstances, consult your agronomist. 

Application rates (0.1 pH Improvement)
Sand/loamy sands4
Sandy/silt loams6.5
Clay/loamy clays8
10-15% Organic matter10.5
+25% Organic matter13

What results can I expect with Omya Top Flow Ca?

Omya Top Flow Ca is proven in independent trials to deliver higher yields than gypsum, calcium sulfate and other commonly used inputs.