Tap water is generally suitable for a wide range of uses.êeven if it contains additives such as chlorine. On the other hand, if the water is very hard in your area, it is not very suitable for citrus fruits. In this case it is more beneficial to use rainwater. Collect it, for example, by placing a can under a gutter.

Adult citrus trees planted in the ground do not need to be watered only if the rain fails to come. 

Indeed, water deficits are becoming more frequent and intense in Europe, even in areas where this did not happen in the past, including Switzerland. However, if rainfall is fairly regular, an additional supply is not required and may even be harmful in case of excess.

In the event of a lack of rain, or even drought, all types of citrus cope very poorly with root drying and this in all seasons, not only in summer. Citrus are evergreen trees and are never in full dormancy.

Monitor the soil moisture level is therefore necessary all year round, not just in spring and summer.

The sensitivity of citrus to drying out is due to its root structure.

They develop a large root that plunges straight down. But the vast majority of roots grow horizontally, in all directions around the trunk, to a depth of no more than 40cm.
This superficial zone is the one to keep under observation to avoid any risk.

For regular monitoring we all have an infallible instrument: the finger.

Plunge your index finger a few inches into the ground, in line with the branches, not near the trunk. Scrape a little if necessary to get in deep.

You can smell a little moisture: no need to water.
It's all dry: you need to give it something to drink.
If you're in any doubt, you're better off watering.

If your finger doesn't go into the soil even when scraping, it is too compacted. See the following paragraphs on mulching.

The tree absorbs nutrients and water mainly through its thinner roots. They are mostly concentrated outside the growth area. For a mature tree, you should water in a circle around the tree, in line with the branches. For a young tree or one that has just been planted, you can just fill the cup at the foot of the tree with water.

The quantity of water to bring for each watering will be approximately 10L. For an adult tree that is already large or in case of heat wave or drought, do not hesitate to double the dose.

There is no regular watering schedule, but rather a monitoring schedule: every two to three days during seasons when there is little or no rainfall.

Hint: In a hot, dry summer, you may find that the soil has dried out every time you check. Then it will be necessary to water up to twice a week.

Avoid rapid soil drying will allow you to space out watering and provide the tree with a more stable environment. For this, protect the soil from direct sunlight.

The method recognized as the most effective is the vegetal mulching. It consists of arranging around the tree a thick layer of 20 cm to 30 cm of cut vegetation, mulch (chopped grass), hay, dry leaves, ferns, garden leftovers, cereal straw, trimmed roots, branch chips. No industrial sawdust and especially no pine bark, which can abruptly change the pH at the base of the tree. The mulching circle around the tree will be about a 50 cm radius, it must fill the planting hole (see Planting) and extend well beyond it. In the centre of the circle leave a little free space around the trunk, to keep the graft scar exposed to air.
Do not pile the mulch directly against the wood.
To avoid it easily you can place removable and airy protections around the trunk. However, avoid rigid tubes without holes around the trunk, as they can harbor pests and restrict growth.

It will be necessary to maintain this layer, as it will settle and assimilate into the soil very slowly.

Mulch is never permanent. It disappears, fades and quietly feeds your tree. It must be renewed, adding new layers, so its soil‑protecting effect against the sun remains continuous.

Besides providing a more stable moisture level for the tree, a thick mulch also serves as a protection for the soil fauna. In the earth, under this shelter, many animals and organisms will take refuge and reproduce, from the tiny to the invisible: earthworms, insects, mites and bacteria. They will dig, aerate, de‑compact and enrich the soil by turning vegetation and fertilizer into nutrients the tree can absorb. Its root network will be healthier, stronger, more dynamic. In compacted soil, mulching is therefore essential.

Mulching also has advantages in winter. Acting as a thermal buffer, it will create a nano‑climate at the base of the tree, add inertia and slow the penetration of cold as well as excessive heat.

Once the tree has grown well, it can become taxing to maintain a permanent mulch. The wider canopy will provide shade around the trunk. This is a first protection.

Don't hesitate to sow a short green manure to better shelter the soil. Look for local annuals that will grow best in your area, clover being among the most common and adaptable. After three years, the citrus fruit is young but already consolidated. Its roots go deep and far, they entered in symbiosis with the mycelium. Mulching is still recommended as it is always beneficial. But it is less critical and can be lightened or even phased out. The adult tree will also begin to make its own humus by renewing its foliage throughout the seasons.

During the first three years after planting, the tree has not yet colonized with its roots the entire space it will occupy as an adult, neither in depth nor in width. It is much more vulnerable than an adult to root desiccation.

Therefore, monitor immature trees with particular care, for their first summer in the ground of course, but also in case of winter drought, without rain or snow.

A thick mulch is even more important for a vigorous initial growth, to be maintained diligently at least until the third year.  Remove wild and tall weeds that can grow even through the mulch. They compete with the very young tree for soil nutrients. 

Never use plastic sails, or worse, PVC tarps, to replace plant mulch. This would have the opposite effect by causing thermal jumps, harmful to the tree and the native microfauna.

If you can't guarantee a plant mulch for your young trees, get some canvas or burlap bags and lay them all around, without pressing them against the trunk, possibly in a double layer. They can provide good sun protection and partially slow the growth of competing wild grasses. Block them with stones or the wind will move them.

Today there are also products studied for an easy and natural mulching of fruit trees, in pre-cut biodegradable pieces.

These products are unfortunately difficult to find in retail stores.

The general principles described above also apply to potted plants. The soil should be kept moist but not waterlogged. Mulching is replaced by coconut discs that are easy to obtain commercially in various diameters. Remove the disc before watering for an even distribution over the entire surface.
The only specific point is toavoid absolutely the sub‑pots. Permanent stagnant water is not healthy for the roots, which can become susceptible to phytophthora and become damaged.

We advise against letting the trees available on this site grow in pots, as they will never reach their natural size and productivity. Unless you use increasingly larger Air-Pots, up to 100–400 liters depending on the varieties, which ensure healthy and sustained growth.