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
Steffen already gave the example of what 600m2 (6458 sq ft) of lawn means...
You don’t need that much if you do it by hand, but it is not enough if you have certain standards. I don’t know how much lawn you have, but 20 liters (5.3 gallons) per week per m2 (10.8 sq ft) is the typical water requirement. Most likely, your annual amount would actually be needed monthly.
It’s all the better if you manage with significantly less.
You don’t need that much if you do it by hand, but it is not enough if you have certain standards. I don’t know how much lawn you have, but 20 liters (5.3 gallons) per week per m2 (10.8 sq ft) is the typical water requirement. Most likely, your annual amount would actually be needed monthly.
It’s all the better if you manage with significantly less.
G
Gartenfreund11 Apr 2020 04:06We have a well and a rainwater cistern here.
My parents had the well drilled. A deep well pump is installed in the well, which has been delivering water to a pressure tank ever since. The only thing that needed replacement after almost 30 years was the pressure tank because it had rusted through. Of course, I also took the opportunity to replace some other parts at the same time.
The cistern was only added a few years ago because the annual costs for rainwater disposal became too high for me.
I got a 4 m³ (1056 gallons) plastic tank and connected the rainwater pipes. All the work was done by myself. And after about 6 years, the system started to pay off financially.
Now, to address what @Pianist would like to know.
Whether a cistern is sufficient for you or not really depends.
The size of the cistern you can or should have depends on the connected area (roof, driveway, etc.), the amount of rainfall, and of course the size of the garden as well as the types of plants growing there. And naturally, it also depends on your budget.
I can only share how it was here during the last two summers. Since our garden is mainly used for growing food, a lot of watering was needed. After all, you want to harvest something. So, an irrigation sprinkler was running somewhere on the property almost every day. Therefore, I assume that at least 3 m³ (792 gallons) of water was needed daily. This means that our cistern, even if it had been full, would have only lasted a maximum of 2 days.
Without the well, it wouldn’t have been possible here.
So if possible, have a well drilled (not driven) with a pipe diameter of at least 125 mm (5 inches). Then install a powerful pump inside, place a pressure tank in the basement, and connect it to the outdoor water supply line.
My parents had the well drilled. A deep well pump is installed in the well, which has been delivering water to a pressure tank ever since. The only thing that needed replacement after almost 30 years was the pressure tank because it had rusted through. Of course, I also took the opportunity to replace some other parts at the same time.
The cistern was only added a few years ago because the annual costs for rainwater disposal became too high for me.
I got a 4 m³ (1056 gallons) plastic tank and connected the rainwater pipes. All the work was done by myself. And after about 6 years, the system started to pay off financially.
Now, to address what @Pianist would like to know.
Whether a cistern is sufficient for you or not really depends.
The size of the cistern you can or should have depends on the connected area (roof, driveway, etc.), the amount of rainfall, and of course the size of the garden as well as the types of plants growing there. And naturally, it also depends on your budget.
I can only share how it was here during the last two summers. Since our garden is mainly used for growing food, a lot of watering was needed. After all, you want to harvest something. So, an irrigation sprinkler was running somewhere on the property almost every day. Therefore, I assume that at least 3 m³ (792 gallons) of water was needed daily. This means that our cistern, even if it had been full, would have only lasted a maximum of 2 days.
Without the well, it wouldn’t have been possible here.
So if possible, have a well drilled (not driven) with a pipe diameter of at least 125 mm (5 inches). Then install a powerful pump inside, place a pressure tank in the basement, and connect it to the outdoor water supply line.
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