NFT Channel Design

NFT (Nutrient Film Technique) hydroponics grows plants along shallow, gently sloped channels where a thin, continuously recirculating film of nutrient solution washes over the bare roots. This calculator starts by dividing your total plant count by plants-per-channel, rounding up, to get Channels Needed — the number of physical channel runs your system requires. Multiplying that by the flow rate you've set per channel gives Total Pump Capacity in gallons per hour (and GPM), which is the single most important spec for sizing your recirculating pump: undersize it and channels at the far end of the plumbing run starve for flow. Plant Spacing divides each channel's length (converted to inches) by the plants-per-channel count, giving even on-center spacing along the run.

The Flow Velocity figure is the calculator's most technical output: it assumes a standard 4 sq inch NFT channel cross-section (a typical 4-inch-wide by 1-inch-deep channel), converts your GPH flow rate to cubic inches per hour, divides by that cross-section to get a linear velocity, and converts to feet per minute. That velocity is then rated against the NFT-standard range of roughly 0.5-2 ft/min: too slow (under 0.3 ft/min) risks stagnant zones and root rot, while too fast (over 3 ft/min) can physically batter and damage the fine root hairs plants rely on for nutrient uptake. Reservoir sizing (1-2 gallons per plant site) is a general rule of thumb for buffering nutrient solution against rapid depletion and temperature swings, not a strict engineering requirement. Because the 4 sq inch cross-section is a fixed assumption rather than an input, results will be less accurate for channels built with a significantly different width or depth than that standard profile.