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Water Retention Reference

Estimated retention by pot size and growing medium

Use this table to estimate your Max Retention Capacity in Evapotrack — the maximum volume of water your medium can hold before runoff begins. These values represent how much water the medium retains after it has fully drained, not the total amount of water it holds while still dripping.

Pot Size Coco/Perlite 70/30 Coco 100% Soil
L gal L gal L gal
1 gal 2.0 0.5 2.3 0.6 1.5 0.4
2 gal 4.0 1.1 4.5 1.2 3.0 0.8
3 gal 6.0 1.6 6.8 1.8 4.5 1.2
5 gal 10.0 2.6 11.4 3.0 7.6 2.0
7 gal 14.0 3.7 15.9 4.2 10.6 2.8
10 gal 20.0 5.3 22.7 6.0 15.1 4.0

These are estimates. Actual retention varies with packing density, amendment ratios, coco texture, and pot material. Fabric pots drain and evaporate faster than plastic — expect slightly lower retention.

For the most accurate number, use the built-in calculator in Evapotrack. Water your medium slowly until you get runoff, enter the amounts, and the app calculates your actual Max Retention Capacity.