Growing Medium Cost Calculator

The three growing media compared here — potting soil, coco coir, and hydroponic media (clay pebbles or rockwool) — differ mainly in how many times they can be reused across grow cycles, and that reusability is what drives the cost gap this calculator is built to show. Soil is modeled as fully single-use: because it depletes nutrients and compacts over a grow cycle, the calculator charges its full per-gallon cost every single cycle. Coco coir is modeled as partially reusable, carrying full cost on the first cycle but only half cost on each subsequent cycle, reflecting that coir can often be rinsed, buffered, and reused a limited number of times before it breaks down.

Hydroponic media is modeled as mostly reusable, at just 10% of its cost on repeat cycles, since inert media like clay pebbles or rockwool don't break down chemically the way organic media does and mainly need periodic sterilizing or partial replacement rather than full replacement. Because reuse only kicks in from the second cycle onward, growers running a single cycle a year will see the three media priced close to their raw per-gallon rates, while growers running many cycles a year will see soil's cost scale linearly while coco and hydro costs grow much more slowly (hydro's total keeps rising with cycle count, just far more slowly than soil's). This calculator leaves out the added electricity, nutrient solution, and equipment costs specific to hydroponic setups, as well as labor time for sterilizing and reconditioning reused media between cycles.