Pots need a different watering plan than garden beds, and this free container watering schedule works it out for you. Enter your pot size, your plant type, how much sun the pot gets, and the temperature on a hot day. You get litres per watering, how many days to wait between waterings, and a weekly total for each pot.
To use the tool, start with the pot size in litres. Most pots show their volume on the base or on the label. If yours does not, measure it: a round pot that is 30 centimetres wide and 30 centimetres tall holds about 20 litres. Then pick the plant type that is closest to yours. Tomatoes drink more than herbs, so the plant type changes the answer a lot.
Next, choose the sun level. A pot in full sun all day dries out far faster than a pot in shade, even when both hold the same plant. Then enter the temperature you expect on a hot day, not the average for the week. The tool plans for the hardest days, because those are the days when pots fail.
The main result is litres per watering. This is the amount to give slowly until a little water runs from the drainage holes. Watering slowly matters: dry potting mix can repel water at first, so a fast pour may run down the sides and out of the bottom while the middle stays dry.
The second result is the gap between waterings, in days. In mild weather most pots need water every two or three days, but in a heatwave a small pot in full sun may need water every day. The weekly total helps you plan, for example when you go away for a weekend and need to ask a neighbour to water.
Pot size changes everything. A tiny pot holds little water and little soil, so it swings between wet and dry very fast. A large pot is far more forgiving. If you struggle to keep a plant alive in a small pot, moving it to a bigger pot is often the simplest fix, and it also means less frequent watering.
The type of potting mix matters too. Ordinary garden soil compacts in pots and drains poorly, so use potting mix made for containers. Mix with plenty of drainage holes is essential. A pot without holes will hold water at the bottom, and roots sitting in water will rot, no matter how careful your schedule is.
Pots dry out much faster than garden beds, because a small volume of soil holds little water and the sides of the pot warm up in the sun. In summer, many pots need a daily check.
Always check before you water. Push a finger two centimetres into the mix. If it feels dry at that depth, water. If it still feels damp, wait a day. This simple check beats any fixed schedule, because wind, rain, and cloudy days all change how fast a pot dries out.
Water in the morning when you can. Morning watering gives the leaves time to dry during the day, which lowers the risk of fungal problems, and the plant has water ready for the hottest hours. Evening watering is fine too, but avoid wetting the leaves late at night.
In summer, group your pots together. Pots shade each other, the air between them stays more humid, and they dry out more slowly. A saucer under the pot can help on very hot days, but empty it after half an hour so the plant is not left standing in water.
Remember that this schedule is general garden guidance, not a rule for every plant. A newly potted plant, a plant in a terracotta pot, and a plant on a windy balcony all dry out faster than the calculator assumes. Use the numbers as a starting point, check the soil, and adjust over a week or two until the routine fits your plants.