How much water for my plants?

This is the big question of all amateur gardeners!

Too much water can rot the roots of some plants or bring various diseases.

Not enough water does not allow the fruit to grow well or worse, the plant dries out and can die.

A magic number to remember: 2.5

Either 2.5 cm or 1 inch of water per week for a plant.

Obviously, all plants have different needs, for example tomatoes usually require more and garlic much less. Excellent books on gardening, like that of Bertrand Dumont, will give you a general indication, little, average, a lot of water. See our summary table at the bottom!

2.5 cm, ok, but in liters? … and what do we mean by 2.5 cm of water? Where is this 2.5 cm?

In fact, this is an average of 2.5 cm of water per week for a plant, which is actually 2.5 cm of water (in height) multiplied by the approximate area of ​​30 cm by 30 cm. cm. This gives us 2250 cubic centimeters of water, or 2.25 liters of water a week! This is a lot of water, you will probably want to water in 2-3 times with less water at a time.

Many plants in a pot or kitchen garden square?

No need to calculate for all plants individually! It’s quite simple, we simply calculate the total area of ​​pot, approximately, or the kitchen area (ex .: kitchen garden square). Examples of calculations below!

A plant or pot VS a whole vegetable garden

If I put tons of plants in a small area, why do not I calculate the water per plant rather than the area as suggested?

The water given to a small single plant, earth or pot, will be lost partly by runoff and by evaporation. In fact, the average measurement of 2.25 liters per week takes into account the losses. However, the more plants there are in a small space, the less water will be lost because the more roots there are to collect the water, the more foliage there is to keep moisture on the ground and prevent evaporation. So you can, for the whole season (except when your plants are in the seedling or small seedling state) trust you to the proposed water calculation.

Example # 1) A red pepper plant
30 xm X 30 cm X 2.5 cm = 2250 cm3, so 2.25 liters per week.

Example # 2) A small balcony pan of 1m by 40cm
100 cm X 40 cm X 2,5 cm = 10,000 cm3, so 10 liters per week

Example # 3) A 4 ‘by 4’ square kitchen garden
122 cm X 122 cm X 2,5 cm = 37210 cm3, so 37 liters per week.

Summary in step

1) The area cultivated (area in cm2) is calculated
2) Multiply by 2.5 cm to give the volume of water. The result is in cm3.
3) We take the volume in cm3 and convert it to liter for it to be more practical! Google cm3 converter in liters

The question will then be: which drippers to choose according to the water needs of my plants, and how long should watering last? See the ticket choose its drippers and the watering time.