Gardening tips: Collect rainwater: bin, tank, cistern – this is a clever way to catch the drops

It's bewitched.

Gardening tips: Collect rainwater: bin, tank, cistern – this is a clever way to catch the drops

It's bewitched. For two weeks not a single droplet fell from the sky. There is a yawning emptiness in the rain barrel. So that the tomatoes, cucumbers and courgettes that have been laboriously brought forward, as well as the lawn, do not die of thirst, the garden hose and thus clear, but usually very calcareous, rather hard water are needed. But suddenly - out of nowhere, the sky opens the floodgates. Within hours, hundreds of liters of the finest rainwater rush through the downpipe into the bin. She has to give up at some point. And the sorely missed water from above seeps away never to be seen again. This can be done better.

We explain how to cleverly collect rainwater. Why round bins are better than square ones - and how to prevent the rain collector from overflowing.

Rainwater is precious. Also because it rains less and less in some regions of Germany. Much more, however, because it contains neither chlorine nor other chemical additives, which many plants in the garden do not like at all. In addition, the soft, well-tempered rainwater does not cost a cent. And it's environmentally friendly too. But what is the most effective way to collect the blessing from above? Depending on how much effort should be, two variants have prevailed. If you like it quick and uncomplicated, you are best advised to use one or more rain barrels. Underground tanks or cisterns are much more complex to install and more expensive, but a lot easier to care for. They hold a multiple of rainwater, but have to be sunk into the ground.

The first choice for allotment gardeners in particular when it comes to collecting rainwater. Rain barrels in all colors and shapes are available in every major hardware store. Usually including lid and water tap. Place on a stable base under the gutter drain, done. Experts recommend collecting rainwater in a round barrel if possible. Here the immense pressure of the up to 1,000 liters of rainwater is distributed more evenly on the wall. Square barrels must be stabilized with aluminum struts. If the bin is full to the brim, the walls could give in to the pressure and burst.

Tip: Always close the water butt with a lid. Open bins are not only dangerous for small children - many insects cannot get out on their own.



compact and space-saving

limited capacity


exposed to UV radiation

no permit needed

usually not frost-proof

convenient water withdrawal

So that you always have enough water in the barrel when you need it; But the water doesn't stand unused in the barrel for weeks and doesn't get dirty, you should analyze your watering behavior. Estimate how many jugs (and thus liters) of water you need on average for watering on a hot day. Multiply that by a factor of ten. Statistically, this is how many days pass between two rainy days in Germany. Three cans of ten liters each result in around 300 liters of water for ten summer days. So the bin should be at least that big. With larger plots of land, you quickly reach your limits. Here the above-ground variant is often not the most efficient solution.

If you want to collect rainwater on a larger scale, you not only have to dig deeper into your wallet, you also have to dig a lot. Because underground tanks or cisterns are usually completely sunk into the ground. These underground tanks hold up to 4,000 liters of rainwater and are connected directly to the rainwater downpipe. The water is removed via an electric submersible pump. The whole thing not only sounds complicated. While underground tanks are usually made of stable, durable plastic, cisterns can also be made of concrete. An automatic overflow drains excess water directly into the sewage system or the ground.

Important: The discharge of rainwater into the sewage system must be approved by the relevant city or municipality authority. In return, waste water costs are reduced if a lot of rainwater is collected and used accordingly.



large capacity

approval required


complex installation

constant water temperature

additional filter required

protected from UV radiation

automatic overflow

Pour precious drinking water on the apple tree or the cucumber is only the second best solution. The treated water from the tap is often not only too cold, but also more or less calcareous and mixed with fluorine or chlorine, depending on the region. This does not benefit many ornamental plants, but also some types of vegetables in the long run. The advantages of rainwater are therefore obvious. It is usually well-tempered and free of all additives that could seep unhindered into the ground.

Sources: ""; ""; Stadtwerke Dusseldorf

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