Topflor comes as a 0.38% active ingredient liq uid (3,800 mg/liter). Assuming a cost of $113/ liter container, the chemical cost of Topflor comes to $113/3,800 mg = $0.0297 per mg a.i. Thus, the chemical cost of a 1, 2, or 3 mg/pot drench is 3, 6, or 9 cents (U.S). per pot, re spectively. These costs are probably too high for 4” pots, but are more reasonable for 6” or larger containers.