Indoor Watering Calculator
Calculate optimal watering frequency, volume, and runoff targets for container-grown indoor plants.
Inputs
Results
Water Every
3 days
Water Amount
0.45 gal
≈ 5 soda cans
How to Use This Calculator
- Enter your container size in gallons — larger pots hold moisture longer and need less frequent watering.
- Select your growing medium: soil retains moisture the longest, coco coir is moderate, perlite/hydro dries fastest.
- Enter your room temperature in °F and relative humidity % — higher temperatures and lower humidity increase water demand.
- Review Water Every (days) and Water Amount (gal) to establish your watering schedule.
- Note the Runoff Target % — always water to 10–20% runoff to prevent salt buildup in soil and coco.
How the result changes with Room Temperature
| Room Temperature | Water Every | Water Amount |
|---|---|---|
| 60 | 3.9 days | 0.45 gal |
| 71 | 3 days | 0.45 gal |
| 84 | 2.4 days | 0.45 gal |
| 96 | 2.4 days | 0.45 gal |
What each input means
- Container Size
- Pot volume in gallons — larger pots hold moisture longer.
- Growing Medium
- Select the growing medium
- Room Temperature
- Higher temps increase evaporation and water uptake.
- Relative Humidity
- Higher humidity slows evaporation from the growing medium.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersContainer Size = 3, Growing Medium = 1, Room Temperature = 72, Relative Humidity = 50 = 4 input(s) provided
- Calculate Water EveryWater Every3 = 3
- Calculate Water AmountWater Amount0.45 = 0.45
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Growing Medium Cost Calculator
Compare annual costs of soil, coco coir, and hydroponic media for your indoor garden.
Indoor GardeningHumidity Control Calculator
Calculate humidifier or dehumidifier capacity needed to reach target relative humidity in your grow room.
Indoor GardeningIndoor Herb Garden Calculator
Plan a kitchen herb garden with container counts, supplemental lighting, and watering schedules.
Garden PlanningGarden Watering Calculator
Calculate weekly water needs for your garden based on size, temperature, rainfall, and soil type.
Garden PlanningIrrigation Schedule Calculator
Plan your garden watering schedule based on plant type, soil, climate, and sun exposure. Get gallons per week, session duration, and cost estimates.
More in Home, Garden & Maintenance.