Irrigation system for a large (still) empty plot

Hello everyone,

last year (oh God, that already sounds so long ago) we moved into our new house in the summer. Since then, there was still a lot to do. And there still is. Now, however, the upcoming work is shifting more and more outdoors.

The well has already been drilled. At that spot, I placed a small shaft, and on this the garden shed is now to be placed. Now the irrigation came to my mind again and I noticed that I would have poor access underground to the shaft once the garden shed stands on top. Because then I would undermine the base slab.

So I have made a few thoughts and read a lot but not everything is clear to me yet.
First of all: Before I make the base slab, I still have to lead the necessary pipes out of the shaft. So drill a hole through the shaft ring and lay 1-x KG pipes 1 to 2 meters beyond the outer edge of the base slab. So that later I can push the water pipe through there when the time comes.
By the way, the sub-distribution for the outdoor electricity will also be in the garden shed later. So I also have to run a cable from the shaft through the base slab to the sub-distribution in the garden shed for the pump. In addition, another 2-3 KG pipes from inside where the sub-distribution hangs under the base slab to outside for all the electricity on the yard. So gate, lighting, control cables for the irrigation valves, etc.

But now to the actual topic: the automatic irrigation

Here in the forum seems to be quite knowledgeable about the topic. Maybe you can give me one or two tips as well.

Below is first our property:



Except for the house, none of it has been implemented yet. All the plants are just planned, but that can certainly still change. The 2nd terrace is currently 10x10m on the drawing. It certainly will not be that big. It is only a placeholder for the approximate later position. But it definitely won't be built in the next 5 years. That brings us to the first point:

1. How do you consider that now? For example, with the 2nd terrace, I would mostly plan the sprinklers as if the terrace will never be built. After all, it's still uncertain if and where exactly it will be built. What do I do with the trees? If I install the sprinklers now and then plant a tree 1 or 2 meters next to it next year. Then there will be a shadow on the axis behind the tree. At first, certainly negligible due to the small trunk diameter, but what if the trunk gets thicker later?

2. What actually should be watered? Lawn, beds, and vegetable garden are clear. I have read different things about hedges. Keyword acclimatization. How about trees? They should actually manage fine, right? Would it be exaggerated to install irrigation only for the first and maybe the second year?

3. For my large lawn areas, I was thinking of Hunter gear-driven rotors. However, these are said to be more susceptible to wind. It’s usually windy here because we are on a small hill. But if everything is planted all around later, there probably won't be much wind close to the ground? Why do you prefer rotators like MP3000 over gear-driven rotors like I20 for example?

4. My father-in-law’s grandfather took care of the well. I think a Grundfos SQ2-55 “is hanging in the hole” there. The drilling depth was about 20m and the pump hangs at about 15m depth. The plot rises by almost a meter to the right. So the pump pumps about 16m upwards. The pump can handle 54m. So 38m remain - which means about 3.8 bar and unfortunately probably only 2m³/h. If I see it correctly, I can therefore only operate two gear-driven rotors I20 with nozzle 4.0 on one zone, since each consumes 0.81 m³/h at 2.5 bar and has a range of 11.9m (10.5m for planning). That will probably be a lot of zones. Or I try to return the pump to the well driller (it didn’t work so far) and buy one with 4 or more m³/h? The question is only whether my well will give up sooner then (clogging with iron ochre?).

5. Assuming I keep the existing pump and end up with 30 zones. What does that look like later in practice? Will each zone for the lawn irrigation be switched on for 30 minutes? And every 3 days? Then I would also have problems with my planned mower robot, which on the large area is almost just driving. In the end, I am left with no time to enjoy the yard because either the mower is mowing or the irrigation is running.

6. It is recommended to start planning at a corner of the property. So, I go for example to the top right and place the first sprinkler in front of the hedge. But where exactly is that? The hedge is very narrow at first but will grow 1-2 m wide over time.

7. The sprinklers all extend during operation and retract afterwards. How robust are they if someone steps on them? Later it looks like I will have a "carpet" of pop-up sprinklers. But the children should of course still be able to play freely.

So, enough for now. Have a nice rest of the Sunday!

Hello Denz,

let's see how I can help you. Basically, you have no special requirements.

1. Plan the zones as if everything is already there. Simply, for example, lay a pipe where a tree/hedge is supposed to go and put an end cap on it. Once the tree/hedge is there, activate it. The sprinklers must reach each other. Therefore, a tree is usually not a problem if it doesn't stand exactly between the sprinklers. Since depending on the tree it is not so good to keep it constantly irrigated, better plan the sprinklers so that you can spare it.

2. I would plan irrigation for new hedges, trees, beds, lawns, etc. You can irrigate, but you don’t have to. It helps especially during the establishment phase. Many hedges react badly to dryness. On this property, you would quickly end up watering several hours a day... Trees can be irrigated either with root irrigation (bubbler) or drip line. Drip line is sensible for hedges. If your different hedge plants have a similar water demand, 2 zones are enough for 50 meters. Drip line runs relatively long to irrigate.

3. The rotators have a lower water consumption, there are pressure-compensated housings, more homogeneous coverage, more flexible (throw distances and angles), combinable with other throw distances without changing the precipitation rate. Therefore, larger zones and also more complex shapes are possible. They are also less wind-sensitive. Gear-driven sprinklers are louder. Gear-driven sprinklers are great for large open areas or before rotators existed. The disadvantage of rotators is the longer runtime.

4. How much shaking capacity does the well have? In any case, the pump is far too small for your project. I looked at the pump curve. At 16 meters delivery height, only max 1.5 m3/h comes out. And that is without all the losses in the pipes. So max an i20 if at all. Therefore, look for a pump with at least 4m3/h, better at least 6m3/h at 20 meters. (e.g. T.I.P. TIEFBRUNNENPUMPEN AJ – AJ 4 PLUS 100/57) Or even bigger. You need a decent volume to irrigate your property.

5. Your property is 2,500 m2. Take a 5,000 m2 robotic mower. Minus the house and traffic areas, it won’t even have to run half a day. How many zones there will be depends on your pump, piping, and sprinklers. With too many zones, the valves and especially the control system become expensive. A proper pump and pipes are much cheaper. The sprinklers do not run 30 minutes. In extreme dry phases, maybe 3 times a week. Optimally max 2 times and early in the morning. Then there is still enough time for the robot. Or two smaller ones and split. You don’t have to irrigate everything in one night. You could do a part on Monday, a part on Tuesday, and then on Wednesday the first area again, etc. Hedges and trees can also run during the day and don’t interfere with the robot mower.

6. Yes, start in the corner. Always calculate with max. 90% range and then place the next sprinkler there. Simply leave one meter for the hedge. You can adjust the angle a bit on the sprinkler heads so that the hedge width can be compensated. The sprinklers have a connection pipe which can quickly be shifted a few cm if something bigger changes. If it is windy, it also goes a bit off sometimes...

7. The sprinklers are robust. You can even drive over them with the lawn tractor. Playing children don’t cause problems either. With 3000 rotators (assuming enough pressure), you would have a sprinkler every 8.50 meters. In more complex areas sometimes a bit closer or if smaller heads are used. You can hardly find the sprinklers after 4 months. Only if they are extended.

How do you want to realize the control?

For your property size, it is important:
- big and strong pump
- large diameter for the distribution pipes. I would even go up to DN40 here (if the pump connection is the same size). But on very short distances, you might also use a 110 KG.
- Then subdivision into several valve boxes with at least DN32. This way you can realize larger zones, still have some flexibility for changes, fewer valves, and shorter runtimes.
- The control cables will be relatively long because you have to lay them from all valve boxes to your control unit. But the trenches are open anyway for the water pipes.

I hope I have answered most of the questions. If you have further questions, just get in touch.

Hello Rick,

thank you very much for your quick response.

Flow rate - How do I find this out?

Yes, the Automower 450X is already planned.

Do I understand correctly that Sprinkler A should not only overlap the irrigated area of Sprinkler B, but actually Sprinkler B itself? So if I have 3 sprinklers in a row, the sprinkler areas of Sprinkler A and C overlap directly on Sprinkler B?

I actually didn’t want to control the system with a classic irrigation controller from Hunter, but rather via KNX and Edomi. Although I still haven’t gotten around to Edomi. (It was actually planned as a winter project)

The earth drill is 3” and the connection above behind the Presscontrol unit is 1”. Accordingly, DN40 doesn’t make sense and I can stick with DN25, or am I mistaken?

What surprises me a bit is the big price difference between the Grundfos pump installed in my system and the pump you suggested. But I also just see that it is a 4” pump and therefore unfortunately “too big” anyway.

Regarding the overlap. Yes, the sprinkler must reach the next sprinkler. So with a throwing range of 10 meters, you have a sprinkler every 10 meters and not every 20 meters. With three pieces in a row as you described. This is the worst mistake regarding coverage and homogeneous precipitation. Therefore, strictly adhere to this. At the sprinkler itself and at the end of the throwing range, the precipitation is lowest.

It makes no sense to go (much) bigger than your pump connection. Only the line losses are lower. 1" is DN32 with about 25-26 internal diameter. DN 25 is 3/4 inch.

There are huge differences in pumps. The Tipp are cheaper and have proven themselves in a few installations known to me. We use Wilo. When I think of well pumps, Grundfos is not the first name that comes to mind. However, they have a name you pay for. Just start looking to see if you can find a pump that has more volume at the delivery height and fits into the hole.

When using DN32 and the line lengths, I would plan the circuits with max 2.3m3/h. Proper pump and valves also assumed in 1".

The 450x is great. I installed it at my mother’s last year. In your garden, it comes close to the theoretical maximum area performance.

You can only measure the flow rate by litering. So run the pump and let it flow into a defined container and stop the time. Whether this is also the continuous performance will only be seen when the pump runs longer...

Control can be done via KNX. Note that you still need an additional transformer for the valves. However, it is by far not as practical and easy as with a modern irrigation controller. Also not really cheaper. The only advantage of control via KNX is that you can activate several circuits simultaneously. But that doesn’t work for you because you can be glad to supply a small circuit... I thought about it for a long time with us and finally decided on KNX. But we can also run 2-3 circuits simultaneously (pump at required delivery height 30m3/h).

4. How much shaking does the well have? In any case, the pump is much too small for your project. I took a look at the pump diagram. At 16 meters delivery height, only a maximum of 1.5m3/h comes out. And that is without all the losses in the pipes. So at most an i20 if at all.

I have now also looked at the characteristic curves. It’s not quite so easy to figure it out. How do you arrive at the 1.5m³/h? When I enter 16m and 1.5m³/h as the operating point, the graph shows a characteristic curve that indicates I still have about 45m delivery height and 2.513m³/h available. In other words, 2.5m³/h at 4.5 bar directly at the top of the shaft.

Ok, with DN32 the outer diameter is meant. I thought inside, that’s why I came to DN25.

Ok. Well, I can still deal with the control at the end. I have to run the water and control lines to the garden house with both variants anyway.

I only took the pump characteristic curve and read it off the diagram. There were also different models in one graphic. The pump has only a nominal volume flow of 2m3/h. But even at 2.5m3/5 you can't even calculate 2m3/h in the circuit....