Watering trees in autumn

For a tree, water is the most valuable thing we can give it. With enough water, trees can handle almost anything: they can photosynthesize, thrive, defend themselves against diseases and pests, and repair themselves. If there is one thing we should do really well with trees that have already been planted, it is watering. There are different challenges for every season. Here you will find the most important information for autumn.

Autumn: closing the year and preparing for winter

The growing year is coming to an end. Fruits and nuts are harvested in autumn. And at the same time it is now getting colder. In autumn the deciduous trees slowly lose their leaves and prepare for winter. But here too it is still necessary that they have enough water. For example, trees produce secondary plant substances in autumn to defend against pathogens and pests.

Tip for autumn: At the end of the growing season, you can water your trees thoroughly again in late autumn, when the deciduous trees have shed their leaves. This should be done before the ground freezes.

The season to plant new trees

Autumn is the best time of year for new plantings for most tree species. Do you still have room for a tree in your garden? Now comes a time when in most years it is not too hot and not too dry. In addition, the trees still have time to develop their root system until spring so that they can really get started in spring.

How do I water properly in autumn?

From September onwards, a tree will mainly need support if it has shown signs of drought stress in the previous months. If you want to harvest fruit and nuts from your tree, it may also be worth supporting the tree with water until this point.
If you are unsure whether your tree has enough water, you can also check the moisture of the soil. To do this, you can dig a small hole of 10 to 15 centimeters in the root area of ​​the tree. If the soil there is dry, the tree should be watered. This is especially important for autumn. Because over-watering can also occur here. If the tree has too much water, it reacts externally in a similar way to drought stress.

All young trees planted in the last 5 years usually require additional irrigation. Their root system is not yet prepared enough to get into the deeper layers. Young and newly planted trees are therefore much more susceptible to drought damage. Make sure they get enough water even in the fall. If it is dry for a long time, you can give 1 - 2 liters of water once or twice a week. 

For autumn, there is also the opinion to stop watering trees in early autumn until the leaves fall. This can prevent trees from sprouting new shoots in the fall that are not strong enough to survive the winter.

Except for frost

If there is already snow or frost in autumn, wait until the snow has melted or the temperatures have risen above 5 degrees before watering.

The right amount of water

The water requirements of trees vary greatly depending on the tree species, age and location. The following rule of thumb is helpful:

During the growth phase, an average tree needs around two waterings, each with 150 to 200 liters of water per week. In the fall, a tree may need less water.

The following applies to all seasons: the lower the temperature, the lower the water requirement.

Which casting method is best?

It is important that the water seeps into the soil as slowly as possible so that it can actually be absorbed by the soil. This is difficult with a quantity of 150 to 200 liters per watering session with a watering can or hose. If the water is released too quickly, most of it flows off the surface without seeping through the soil in depth.

A very effective tool for this are tree watering bags, which slowly release water using drip irrigation. They can be installed without much effort and can be filled with a garden hose in just a few minutes. They then release the water drop by drop into the ground over a period of 6-9 hours. This means there is no runoff and no rapid seepage through the root area.

If you use tree watering bags, it is important not to leave them on the tree for long periods of time in the fall. Because of the dew and moisture, algae can build up.
If it falls below 5 degrees Celsius at night, you should remove the bags overnight.

Watch for signs of drought stress

The typical signs of drought stress are:

• Dried, drooping, curled, or folded leaves
• leaf wagging or trembling
• shedding of leaves
• shedding of branches
• Formation of excessively large and small fruits.

We should support our trees with watering at the latest when these signs appear. Here is a text on the topic drought stress in trees.

Avoid fertilizer and instead mulch

In the fall you should avoid fertilizer as it could stimulate growth. It is much more helpful to mulch the soil around the tree. Mulch can help retain moisture over the winter months and also protects against the cold.

Different every year

We are currently experiencing frequent extreme weather events. Sometimes it rains a lot in autumn, sometimes it has been hot and dry for a long time. It is therefore increasingly difficult to have blanket solutions.

Here is a more detailed text on the subject Water trees.