Mini sprinkler for sprouts

I don't know if it is the right section, sorry for any mistake but I'm pretty new.
I'm trying to build my own sprouting system for every kind of sprouts.
Obv, there are a lot of prepackaged tool, but they are very expensive considering that they are only made of plastic! So, I fend with some cheapest solution (stacked colanders and collector for water).
Now, I'd like to improve my own "creation" adding to it a mini-sprinkler to sprinkle water at predefined intervals. The idea is similar to the "FL-2000 Automatic Sprouter", where you can see the helical sprinkler at the top of the sprouter.
However, I don't know where to start and what to buy and I'm here to ask your help.

Thanks in advance to everyone.

Absolutely the right place to post.

I'm afraid I can't help, but i'm sure someone can. When I saw "sprout" in your title, I though of Brussel sprouts. I'm very partial to Brussel sprouts.

Hello !

I have spent quite a bit of time trying to make an automatic watering system for my greenhouse plants, so I don't have to visit them every day.  Maybe there is some similarity.

Most of my effort was in sensing when to water.  I started with a bit of homemade electronics to measure soil electrical resistance between two stainless steel probes, and automatically turn on a valve when the resistance was too high (soil dry).  It worked well enough to keep plants alive if they were in the shade, for a week or two whilst I was on holiday.  But it could not keep them well enough watered to use all the time.  So I tried various other methods to measure soil moisture - electrical resistance, capacitance, etc - then finally went back to a simple timer because after all that, it gave better results !

But the thing that might interest you is how I eventually delivered the water to the plants.  I used a water tank in the greenhouse below the bench, which means that the water is not so cold as straight from the tap.  To move the water, I used a pump - specifically a computer water cooling pump like this one.  The pump needs to be below the level of the water in the tank (it does not self-prime well), but can lift water 2 metres or so - plenty enough to water the plants on the bench above.  They need to be above the water level in the tank to avoid siphoning all the water even when the pump stops !

You can then use commercially available spray nozzles or drippers to apply the water to the plants.  Putting the pump on a timer is simple - I used a 240V mains timer (an old mechanical one), switching a little 12v power supply.  The pump is 12v 6.5W, so it is fairly easy to find a power supply from a broken electronic gadget (WiFi router, etc, etc) that will do the job. That way I can make it water for 1/2 hour, twice a day, without me being there.

I hope this makes sense to you, and just maybe some use ?

Chilli-head wrote:...

Hey, thanks for your help, I really appreciate it. Oh and sorry for the delay, didn't received a notification at all
I carefully read and reread the whole message to search for a way to adapt to the mini-garden I created.
Well, I came to the conclusion that I need (correct me if I am wrong)
- container for water, something like a bowl
- a mini pump like the "SDMP306 pump" (I can't post link, I'm sorry). Can i directly connect the pump to the power point/timer or I need something else?
- a timer to activate the pump every X hours. Are these kind of timer produced? I mean, I've only seen timer that activate at hour X every day, but never seen one that activates every X hours. Can you provide a link or useful specifications to search on?

Thanks again for your help.

Check your email address in your profile, and the "Watch this topic for replies" link at the bottom of the thread - it should work I think.

That pump is an interesting one, but 7 ml/min is not a lot of water - about one drip per second. The supply voltage is potentially exciting too. One of the things I liked about the computer cooling pump is that it is 12v powered, so the parts near the water are low voltage and safe, with a power supply plugged in somewhere dry. One other point is that the one I used is a centrifugal pump, which can operate with the output restricted - so you can feed adjustable drippers from it without risk of burning out the pump when the flow is restricted.

Timers - I just used a mains 24 hour time switch set to turn on once for half an hour in the morning, and once in the afternoon. Mine you can have any number of ons and offs, but the on periods can't be shorter than half an hour. It is OK for my application, but other types might be more suitable for you.

How big is your set up ? any pictures ?

Chilli-head wrote:
That pump is an interesting one, but 7 ml/min is not a lot of water - about one drip per second.  

I don't know, maybe it's just enough. Sprouts need to be moistened 2-3 times per day; of course, it's the same if you moist them more frequently.

The supply voltage is potentially exciting too. One of the things I liked about the computer cooling pump is that it is 12v powered, so the parts near the water are low voltage and safe, with a power supply plugged in somewhere dry.

Yes, the 12V power is pure gold for me. I have an old power supply for a PC: can I use it in some way to connect the pump to the mains?

 One other point is that the one I used is a centrifugal pump, which can operate with the output restricted - so you can feed adjustable drippers from it without risk of burning out the pump when the flow is restricted.

I don't know anything at all about pumps except that they bring liquids What are the risks associated to a non-centrifugal pump?

Timers - I just used a mains 24 hour time switch set to turn on once for half an hour in the morning, and once in the afternoon.  Mine you can have any number of ons and offs, but the on periods can't be shorter than half an hour.  It is OK for my application, but other types might be more suitable for you.

If the pump's flow is too low, maybe I can also avoid to use a timer. I mean, there is something similar in commerce with a permanent watering system. If you can, take a look at the "freshlife 3000 automatic sprouter" (I can't provide links); I'd like to realize something similar.

How big is your set up ? any pictures ?

I don't have pictures right now, but it's very similar to that of the "freshlife sprouter"; only more spartan

tigerjack89 wrote:

Chilli-head wrote:  One other point is that the one I used is a centrifugal pump, which can operate with the output restricted - so you can feed adjustable drippers from it without risk of burning out the pump when the flow is restricted.

I don't know anything at all about pumps except that they bring liquids What are the risks associated to a non-centrifugal pump?

Ok.  There are a few types of pump.  The one you mentioned is a diaphragm pump, which is a fixed displacement type of pump.  Which is to say that for each stroke of the pump, it moves a fixed amount of water.  They are good if you want a constant flow rate. If you restrict the output, the pressure will rise,  and the pump will work harder to deliver the same flow, up to whatever maximum pressure rating it has.  Some pumps have a built in pressure relief valve to prevent overload and damage.

The type of pump I used is a centrifugal pump;  it uses a spinning rotor, water enters at the middle of the rotor and is flung outwards, making the flow.  This is the type of pump used in washing machines etc.  They tend to give a pressure which depends on the rotor speed.  You can then set the flow by restricting output, e.g, using small holes in the spirnkler or drippers, and the pump is less likely to be overloaded by it.

I had a look at those sprouters.  They do seem rather elaborate and expensive. I just rinsed my seeds daily in fresh water, and strained off the excess.  You still need to change the water daily with those fancy sytems too !  I'm sure an improvised solution would do a satisfactory job, with or without automatic watering.

Chilli-head wrote:
...

Thanks for the great explanation, now it's more clear

I had a look at those sprouters.  They do seem rather elaborate and expensive. I just rinsed my seeds daily in fresh water, and strained off the excess.  You still need to change the water daily with those fancy sytems too !  I'm sure an improvised solution would do a satisfactory job, with or without automatic watering.

Yeah, not quite elaborate indeed, but quite expensive! I'm using a simple system composed by staked colanders and a collector for water at the bottom of them.
Well, I'm also using other systems, but this is the main one.
Now, I'd like to improve the system using this simple watering system