Free gardening tools and calculators
A set of free gardening calculators: NPK fertilizer dosing, soil and pH analysis, spray-mix amounts, light metering (lux) and grow-light sizing (DLI). No sign-up, online and offline.
NPK Fertilizer Calculator
Free NPK fertilizer calculator: convert fertilizer rate to your bed area, match a fertilizer to a soil-test deficiency and compare nutrient content (N, P, K). Online and offline.
Soil Analysis & pH Tool
Free soil test interpreter: pH, phosphorus, potassium, magnesium, calcium, organic matter and micronutrients. Optimal ranges, liming rates and fertilizer advice.
Spray Calculator
Free spray-mix calculator: convert product and spray-liquid amounts to your bed area or plant count. Ready-made products and home-made mixes. Online and offline.
Light Meter (lux)
Free phone light meter: measure your bed’s light level in lux and check whether the spot is full sun, partial shade or shade for your vegetables.
Grow Light Calculator
Free grow-light calculator: convert watts to lumens, lux, PPFD and DLI. Size the power and height of an LED/HPS lamp to your grow area and plant.