How to set Loxone irrigation without soil moisture sensors

[mariusmartocsan]

So,
I have 8 zone for irrigation each has its own electrovalve and have a Vegetronix sensor, but, somehow they dont work as expscted, tried different options like burried, outside at 45 degree, etc. Somehow they keep showing me as the soil is always moisture, even if the plants seems to have some problems because of the heat, and on grass (turf) at surface the soil is exremele dry and cracked. So i guess i need an option without those soil moisture despite i spent a lot of time and money to have them ...


Now, the irrigation sistem is made with RainBird XF and XFS Subsurface pipelines, with 2.3l/h, i attached the pictures.

Depends on the zone, some of them have lots of pipes, the presure varies from 1.5 bar to 3 bars. All drip are presure regulated so the amount of water is distribuited equal.

The efficiency they say is 90% as they dont have lose because of evaporation.

How can i calculate how many minutes should i leave each zone based on wheather, presure on pipeline and volume of water per hour.

I found somehting on the forum but is related to sprinklers and avaporations.

Also there they use a 4 days timeframe înd history of waheter precipitation in mm.

Any advice would be welcome. Thanks.

[Jan W.]

I'm not sure which answer you would expect? There is no easy formula that would work in all cases - otherwise Rainbird and others would have offered formulas on their website. The amount of water for irrigation depends on multiple factors: e.g. your location, soil, choice of your plants (density, size) (or lawn), shade, number of pipes per meter - "lots of pipes" is not something useful for a calculation, direct sunlight / radiation, temperature humidity, wind speed near bottom, type of soil, rainfall, evaporation, surface - these are just a few parameters that came in my mind, some of these may be included in others, but I just want to point out that there is not answer like "I have this pipe, so that is the correct formula". Without any information about your situation (except the model of the pipes), nobody in the forum might be able to answer your questions.

Just my opinion: it may be more straight forward to fix the problem with the soil sensor than to use a complicated formula (if there is any) that needs a lot of other sensors / inputs, guesswork and/or uncertainty. Of course you may be able to get some values from weather stations nearby for free, but e.g. radiation from sun and rainfalls needs to be from a station that is very close to your location. A formula that is based on forecasts may not work well, but forecasts may be useful e.g. to prevent irrigation if forecasts predicts rainfall. Typically a forecast does not say that it will rain e.g. 10mm, but rather there is a chance for rainfall of 50% with 5-10mm within 24h.

The question is, do you really need a precise formula as your questions and pictures indicate? Your neighbors might have similar irrigation pipes, but no smart home. So they need to start / stop irrigation manually. You could try to ask somebody (or yourself, if you don't have such a neighbor) how long and often he waters his garden and then you could implement this into Loxone, e.g. a timer, maybe with some intelligence from forecasts and sliders to adjust the length / frequency manually. After some time you might have a system that works well.

At the end also the source of water matters - do you have your own well or do you have to pay for every liter? Sensors may be very helpful if you are not onsite every day or don't want to care about irrigation. A sensor for soil moisture may also help you to stop irrigation if a certain level of moisture has been reached. Without such a sensor, you may have to water much longer - just to be on the safe side. Even with one working soil moisture sensor per zone, you'd only get 8 values. What about depth of the sensor and roots of your plants? Lawn would be very different to trees. Does your zone is exactly the same as the spot with the sensor? A sensor may be useful to get some feedback without digging, but placement is important and it should not be the only input.

In my opinion, a rough formula with some input like temperature and rainfall to adjust the duration for irrigation might work well if you are able to adjust the influence of these parameters over time. Soil sensors may improve the system to raise an alert if soil is too dry, there is a fault in the system and for fine tuning.

[mariusmartocsan]

I know what you mean, is not just the pipeline specs.

1. The soil on top is sandy/clay like 10-15 cm and under is clay soil.
2. The pipeline are around 25-30 cm at a adeep of 9-12 cm.
3. I have the wheather station from Loxone, i have 10 years of service for wheather forecast.
4. The sensors are burried for grass (turf) at their root levels, and other for the plant are at 25-30 cm, ar root levels for shrubs and small plants. However, they always seems o inidcate same value despite of 2 weeks with no rain, they say around 100% moisture, or the value changed insighnifiant. Also tried to get out the sensor as someone on forum recomandaed and use it on top of soil introduced at 45 degree. Same thing. So this is why i say Vegetronix sensors are not good at all, for me, or maybe i am doing something wrong, any alternative? ...
5. Ok, i dont need an excat formula, but some advice how to automte the irrigation, after all, we want an automated house, not one to check each day and adjust all the time the amount of water.
6. Nobody in the zone or maybe in the city dont have burried pipes for grass, most of them use sprinklers.
7. The source of water is a hole at 25 m in ground, and is pumped out, so it should not be a cost problem, before it was from main city line and indeed was very expensive to use a lot of water.

[Iksi]

Hey,

In the loxwiki is an article about irrigation by evaporation.
The amount of water is calculate by Temperature, humidity and rainfall.
In the Wiki you get just an Faktor to multiply with an defined amount of water. But you can use the wiki also to calculate the amount of water which is really needed. The value is in mm/m^2 respectively l/m^2

Then you must just multiply the calculate value with the size of the area to get the amount of water you need.

[Martin1234]

Hi mariusmartocsan,

I am also on the same topic at the moment. But before automatizing this you need some experience with your garden and your plants and lawn. Of course you can water everything every second day to make sure there is never too less water available. If you don't have to pay extra for the water this is a valid approach. But if you take it more seriously you will notice that to water to often, e.g. every second or third day, will cause bad gras as poa annua or poa trvialis. Depending on your soil and the kind of gras I would recommend to water every 5 to 8 days (sandy soil needs more water). For the amount you can use the evaporation like Iksi recommended.

In the loxwiki is an article about irrigation by evaporation.
The amount of water is calculate by Temperature, humidity and rainfall.

Nevertheless I highly recommend to buy yourself a simple and cheap tool to measure the soil humidity on different places and in different depth. Mine is from Dr.meter, costed 11EUR and helps me a lot to decide how often and how much to water.

My experience so far:

• A sensor just on one place is by far too less, because some areas get more sun light and so need more water. Also the rainfall is not the same on all spots in the garden. Some meters directly behind my house I have usually the half of precipiation. Therefore I rejected my plan to install such a soil sensor.
• I plan to water every 7 days with 10-20l per sqm depending on the evaporation.
• Watering on a windy day or night is to be avoided.
• At the beginning I won't let Loxone decide by it's own when to water. I will trigger it manually to be done in the night by Loxone.

Good luck!

[mariusmartocsan]

Dont have sprinklers, so egicency is 90%, doesnt maytter if is windy, my pipelines are underground, and now water is lot during irigation. Also i have 8 sensors ... so yeah, i have so much because the zones are based on sunny/shadow place. But the sensors from Vegetronix kepp showing almoust maximum value all the time. Doubt the soil is always 100% moist.

[Martin1234]

Then check it manually with an analog tool. Check also Youtube, maybe someone is using Subsurface pipelines for grass there. This is not very Loxone specific.

[Martin1234]

Now, the irrigation sistem is made with RainBird XF and XFS Subsurface pipelines, with 2.3l/h, i attached the pictures.

May I ask you which kind of plants you are irrigate with this pipeline. Bushes, trees, hedge? Not the lawn, am I right? My experience with the same but on laying on the surface is that it is great for older plants with deeper roots, but quite bad for seedlings. These you have to irrigate manually at the beginning.

For the older ones I assumed that the roots are deep and so I don't need to irrigate them every week. Every 14 days should be fine. It's hard to say how much the moisture is in a depth of 50cm. How much water would you irrigate after such a long time when doing it manually. I would say about 2-3 liters every 30cm. The rainbird pipeline drops 2,2l per hole per hour. So with 60-80 minutes after 2 weeks I am fine.

[mariusmartocsan]

Grass/turff is 50% and 50% are small plants, max 2 m height.

[mariusmartocsan]

Hey,

In the loxwiki is an article about irrigation by evaporation.
The amount of water is calculate by Temperature, humidity and rainfall.
In the Wiki you get just an Faktor to multiply with an defined amount of water. But you can use the wiki also to calculate the amount of water which is really needed. The value is in mm/m^2 respectively l/m^2

Then you must just multiply the calculate value with the size of the area to get the amount of water you need.

I know, been there but doesnt help me to much, i will try to read again and see if something came up.

[Martin1234]

I know, been there but doesnt help me to much, i will try to read again and see if something came up.

If you would usually irrigate 15l per squaremeter you can multiply this value with the resulting factor of the evaporation 0-200%. Very useful. The 15l should be according to your experience.

[mariusmartocsan]

How often? there is almoust no evaporation, So 15 l pe sqm each day? Each week? each 3-4 days? Each 5-8 days?

[Martin1234]

That there is no evaporation is for sure incorrect. At least the plant is emitting some water over the leaves. So it absolutely makes sense to use the evaporation calculation. It's really super easy.

[Martin1234]

I just had a look at the XFS subsurface pipelines at Youtube. This is not so much fun for the kids, but great!
But I don't think I can give you a good advise here. Can't you ask the company which installed it? If water is not a price factor for you you could start with 10l per sqm every 5 days. But I am also not sure whether it migth be better do irrigate more frequently and with less water. On the other hand the water needs to drain from the pipe to the surrounding soil so you will need some amount of water per cycle.
No rule from Rainbird?

[mariusmartocsan]

not realy, seen somewhere else an advice for clay soil to irrigate in steps, like 5l stop few hours then again 5L, as the clay soil takes more time to absorbe the water.

[Martin1234]

If nothing is available on the web page you can also ask some guys on Youtube. Sometimes you can get great information.