Hydroponic Calculators

Convert between electrical conductivity (mS/cm) and total dissolved solids (PPM) on the 500 and 700 scales. Useful for cross-referencing meter readings across brands.

Calculate the daily, monthly, and annual electricity cost of running grow lights and pumps. Useful for budgeting a new setup or sizing your ongoing power bill against a reservoir or cycle length.

Pick a plant and a sow date; get calendar windows for germination, seedling, vegetative, and harvest-ready stages. Windows are days-from-sow per each plant's published growth-cycle data.

Compute daily light integral (DLI) in mol/m²/day from your fixture's PPFD and photoperiod. Optionally compare against a selected plant's published DLI range.

Recommend a daily photoperiod for a selected plant. Uses the plant's published photoperiod where available, or falls back to a labelled 14-hour default for species without published guidance.

Calculate how many mL of each nutrient part (A/B/C) to add to a hydroponic reservoir, based on the selected plant's per-stage EC target. Only plants with per-stage EC data are listed — omission is intentional under the site's absence-over-fabrication policy.

Calculate how much pH Up or pH Down to add to move a hydroponic reservoir toward a target pH. Defaults target to the selected plant's preferred range; always retest after 15 minutes.

Estimate how many plants fit in a tray at the species' published spacing. Shows both the area-density estimate and the grid-geometry estimate, then a conservative recommendation.

Estimate days between reservoir top-ups for a given plant count, reservoir size, and per-plant daily transpiration. Defaults use the Cornell CEA Hydroponic Lettuce Handbook midpoint for mature leafy greens; override with your measured rate for best results.

Estimate annual harvest weight for a plant at a given plant count and cycles per year. Output is bracketed across the plant's published yield range — conservative, expected, and optimistic figures.