Good day!
The ongoing dry spell has brought up a topic again that I have postponed several times: Where should the water for garden irrigation come from? Until now, I have been using water from the public supply: always available, consistently good pressure, and fairly cost-effective thanks to separate metering. But it probably isn’t sensible to let high-quality drinking water soak into the garden soil.
Is there a general rule of thumb about which form of garden irrigation is best from both financial and ecological perspectives? Essentially, there are three options: water from the public supply, collecting rainwater from roofs in cisterns, or drilling a well (if permitted).
To make the use of rainwater worthwhile, you would need to store a large volume, at least 20 to 30 cubic meters (700 to 1,060 cubic feet) to cover dry periods. The costs for cisterns and the associated earthworks would accordingly be high. Then there are ongoing expenses, such as electricity and maintenance for the pump. Drilling a well also involves costs, plus electricity and pump maintenance. The advantage of a well is that you don’t have to worry about storage capacity.
My garden irrigation system (drip hoses under mulch) consists of four zones, each of which requires one cubic meter (35 cubic feet) per hour. During prolonged dryness, I would ideally run each zone for one hour every two to three days. That adds up to about ten cubic meters (350 cubic feet) per week. With 30 cubic meters (1,060 cubic feet) of storage, this would last just about three weeks. We are increasingly facing situations in Berlin where it doesn’t rain for well over three weeks.
Has anyone here already worked through this in detail?
Matthias
The ongoing dry spell has brought up a topic again that I have postponed several times: Where should the water for garden irrigation come from? Until now, I have been using water from the public supply: always available, consistently good pressure, and fairly cost-effective thanks to separate metering. But it probably isn’t sensible to let high-quality drinking water soak into the garden soil.
Is there a general rule of thumb about which form of garden irrigation is best from both financial and ecological perspectives? Essentially, there are three options: water from the public supply, collecting rainwater from roofs in cisterns, or drilling a well (if permitted).
To make the use of rainwater worthwhile, you would need to store a large volume, at least 20 to 30 cubic meters (700 to 1,060 cubic feet) to cover dry periods. The costs for cisterns and the associated earthworks would accordingly be high. Then there are ongoing expenses, such as electricity and maintenance for the pump. Drilling a well also involves costs, plus electricity and pump maintenance. The advantage of a well is that you don’t have to worry about storage capacity.
My garden irrigation system (drip hoses under mulch) consists of four zones, each of which requires one cubic meter (35 cubic feet) per hour. During prolonged dryness, I would ideally run each zone for one hour every two to three days. That adds up to about ten cubic meters (350 cubic feet) per week. With 30 cubic meters (1,060 cubic feet) of storage, this would last just about three weeks. We are increasingly facing situations in Berlin where it doesn’t rain for well over three weeks.
Has anyone here already worked through this in detail?
Matthias
Self-sufficiency is always a good thing, but if you spend a lot of money for four weeks of self-sufficiency and actually need three months because it simply doesn’t rain, in the end, it is quite uneconomical. It would probably be possible to precisely calculate the required capacity of a cistern at a specific location so that incoming rainwater and irrigation demand match as closely as possible...
This is quite easy to calculate. You just need to know the surface areas where you collect water and the location. Then you have the maximum size you can fill with rainwater.
With an additional well, you can size it significantly larger. This way, you can collect continuously, even in winter.
Where we live, you also pay fees for sealed surfaces. This charge is waived if you have a cistern.
We have a 76 m³ (2,683 ft³) cistern and an old well.
How long it lasts also depends on the garden. Usually, 4 weeks is sufficient. We have estimated about 6 to 8 weeks, including pumping from the well.
With an additional well, you can size it significantly larger. This way, you can collect continuously, even in winter.
Where we live, you also pay fees for sealed surfaces. This charge is waived if you have a cistern.
We have a 76 m³ (2,683 ft³) cistern and an old well.
How long it lasts also depends on the garden. Usually, 4 weeks is sufficient. We have estimated about 6 to 8 weeks, including pumping from the well.
50€ for garden water??? No garden or no irrigation?
If you need so little, you don't have to worry about it.
In many areas, the choice of whether or not to install a cistern is taken out of your hands. Mostly, these are retention cisterns.
For those who have a few square meters of space and want to maintain it even during dry periods, it’s worth considering. We, in the south, don’t have water shortages, but the water is very hard. Another reason to use rainwater. Gardening is a hobby...
Otherwise, you might as well choose a smaller plot or let it grow wild.
If you need so little, you don't have to worry about it.
In many areas, the choice of whether or not to install a cistern is taken out of your hands. Mostly, these are retention cisterns.
For those who have a few square meters of space and want to maintain it even during dry periods, it’s worth considering. We, in the south, don’t have water shortages, but the water is very hard. Another reason to use rainwater. Gardening is a hobby...
Otherwise, you might as well choose a smaller plot or let it grow wild.
rick2018 schrieb:
50€ for garden water??? No garden or no irrigation?
If you need so little, there is no need to think about it.
In many areas, the choice of whether to use a rainwater harvesting system is taken away. These are usually retention cisterns.
Anyone who has a few square meters of area and wants to maintain it even during dry periods should consider this. We in the south don’t have water shortages, but the water is very hard. Another reason for rainwater. Gardening is a hobby...
Otherwise, you might as well take a smaller plot or let it go wild. A typical single-family house today is built on 400–800 sqm (4,300–8,600 sq ft), and irrigation systems are used in a very small percentage of cases. Our lawn stays green despite hot summers, and the plants are doing well. 30 cubic meters (30,000 liters, 7,925 gallons) are sufficient here.
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