Plant Watering Calculator
Get personalised watering schedules for houseplants and garden plants based on plant type, pot size, season and whether it is indoors or outdoors.
Water Every
5 days
Approximately 1.4 times per week
Water Amount
300 ml
Per watering session
Signs of Overwatering
Yellow leaves, root rot, wilting
Signs of Underwatering
Brown leaf tips, wilting, slow growth
Quick Tips
- Feel the soil before watering - it should be slightly moist, not soggy
- Water less in winter when growth slows
- Outdoor plants need more frequent watering than indoor
- Use room temperature water, never cold
- Water in the morning to reduce fungal issues
These are general guidelines. Adjust based on your local climate, humidity, soil type, and whether the pot has drainage holes.
Plant, Season and Pot Size All Change the Answer
Watering schedules depend on the plant, the time of year and the container. A monstera in spring wants 250 ml every 7 days; in summer the same plant needs 300 ml every 5 days; in winter it drops to 150 ml every 14 days. A snake plant on the next shelf goes much longer between drinks - 100 ml every 14 days in spring, easily 21 days in winter. The calculator stores per-plant data for 10 common species so the schedule is plant-specific rather than generic.
Pot size matters too. A 15 cm pot drains faster and dries out quicker than a 30 cm pot of the same plant. The calculator adjusts amount and frequency for pot size. Indoor plants generally need less water than outdoor (less wind, lower light), so a tomato outdoors in a 30 cm pot in summer can need 500 ml every day, while the same plant indoors might need only 250 ml every 2 days.
How to Tell When to Water (Without a Calculator)
The finger test still beats any schedule. Push a finger 2 to 3 cm into the compost; if it feels dry at that depth, water; if it feels damp, wait. Heavy plants (cacti, succulents, snake plants) want to dry out completely between waterings. Thirsty plants (tomatoes, herbs, peace lilies) want consistent moisture. The calculator gives a starting frequency; the finger test fine-tunes it for your specific home, light level and pot.
Symptoms cut both ways. Yellowing leaves are usually overwatering (root rot suffocates the plant). Brown crispy leaf tips and wilting are usually underwatering. The calculator lists the typical symptoms for each plant so you can debug a struggling plant. For the seed-spacing question that often comes up at planting time, [Seed Spacing Calculator](/seed-spacing-calculator) handles row and plant distances.
Frequently Asked Questions
How often should I water houseplants?
Most popular UK houseplants want watering every 7 to 14 days in spring and summer, every 14 to 21 days in autumn and winter. Cacti and succulents stretch to 21 to 30 days. Tropicals like peace lilies and ferns may need watering every 3 to 5 days in summer. Always check the soil before watering rather than sticking rigidly to a schedule.
Can you overwater plants?
Yes, and it is the most common way houseplants die. Overwatering drowns the roots and creates conditions for root rot fungi. Symptoms include yellowing leaves, mushy stems at soil level and a sour smell from the compost. Most plants recover from one missed watering; few survive prolonged overwatering.
Should I water plants in the morning or evening?
Morning is best for outdoor plants in summer: water reaches the roots before the heat of the day, and leaves dry by nightfall (wet leaves overnight encourage fungal disease). Indoor plants are less sensitive but morning watering still slightly outperforms evening because the plant uses water during its active light hours.
How do I know if my plant needs less water in winter?
Most plants slow growth in winter (lower light, cooler temperatures) and use less water. The calculator's winter setting reduces frequency by 30 to 50 percent compared to summer. If a plant is putting out new leaves and growing actively, treat it as in active season; if it has stopped producing new leaves, treat it as dormant and water less.
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