Plot area calculator
Calculate plot area in square metres, ares and hectares. Supports rectangle, triangle and circle shapes. Free online calculator, no sign-up.
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Plant Watering Calculator
The plant watering calculator helps you estimate how much water your garden needs over a week and each day. Simply enter the area of the planting, choose the plant type and the current season to receive a recommended water dose in litres plus an approximate number of ten-litre watering cans. The tool is handy for planning irrigation of lawns, vegetable beds, flower borders and shrub plantings, helping you avoid both overwatering and drought stress.
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How the calculator works
The calculator performs a simple calculation in a few steps: 1. Takes the base water requirement for the chosen plant type (lawn 15, vegetables 25, flowers 18, shrubs 10 litres per m² per week). 2. Multiplies it by the planting area you entered. 3. Applies the season factor (spring 0.8, summer 1.3, autumn 0.6). 4. The result is the weekly water requirement in litres. 5. Divides it by 7 for the daily dose and by 10 to estimate the number of cans (rounded up).
Calculation example
A 50 m² lawn in summer: the base requirement for a lawn is 15 L per m² per week and the summer factor is 1.3. Weekly need = 50 × 15 × 1.3 = 975 litres. Daily dose = 975 / 7 ≈ 139.29 litres. Number of cans = rounded up 975 / 10 = 98 cans of 10 litres each.
Frequently asked questions
How much water does a lawn need per week?
A lawn needs on average about 15 litres of water per square metre per week in the base season. In summer the requirement rises by roughly 30 percent due to higher temperatures and evaporation, while spring and autumn need less. For a 50 m² lawn this means roughly 450 to 975 litres per week depending on the season.
How does the calculator estimate water needs?
The calculator multiplies the planting area by the base requirement of the chosen plant type per square metre and by the season factor. The result is the litres of water needed per week, which it then divides by seven days for the daily dose and by ten litres to estimate the number of full watering cans.
Why do plants need more water in summer?
Summer brings the highest temperatures and the most intense evaporation from soil and leaves. For this reason the calculator applies a factor of 1.3 in summer, increasing the requirement by 30 percent over the base season. Spring uses 0.8 and autumn 0.6 because cooler air and shorter days reduce water needs.
How much water do garden vegetables need?
Vegetables are among the most water-hungry crops, so their base requirement is around 25 litres per square metre per week. Tomatoes, cucumbers and courgettes during fruiting need regular and generous watering to keep the produce firm and flavourful.
Is it better to water daily or once a week?
For most plants, less frequent but generous watering is preferable because it encourages roots to grow deeper into the soil. The daily figure from the calculator is an averaged guide; in practice you can combine several days into one larger watering, especially for lawns and shrubs.
What time of day is best for watering?
Early morning is best, when temperatures are low and water can soak in before the heat of the day. Evening watering is also acceptable, but wet leaves left overnight encourage fungal disease. Avoid watering in full midday sun when evaporation is greatest.
How many litres does a typical watering can hold?
The calculator assumes a standard 10-litre watering can, which matches popular garden models. The number of cans is rounded up because the last can must still be filled even if it is not used completely.
Does soil type affect watering?
Yes, soil matters a great deal. Sandy soils drain quickly and need more frequent watering with smaller doses, while clay soils hold moisture longer and tolerate less frequent irrigation. The calculator gives indicative values for an average garden soil.
Are the calculator results accurate?
The results are indicative and serve as a quick estimate of water needs. Actual requirements depend on rainfall, soil type, sun exposure, wind and the specific plant species. Treat the values as a starting point and adjust them to the conditions in your own garden.
Results are indicative only. Adjust them to rainfall, soil type and current weather.
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