Weekend Solar Garden Watering Project

peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
I have had a plastic tank kicking around around for several years that a friend dropped off. It used to hold wood glue but has been rinsed out a few times including an acid/alkaline wash so is fine for garden watering. When I first built my house it was in a new development and it took ten years for an uphill house to be built. I switched to a deep artesian well before the septic tank went in on the other side of the street. Despite being on a hill, there is a layer of hardpan clay about 2 to 4 feet deep. My surface water well coincidentally sets in a low spot of the hardpan and the bottom is about 15 feet deep. For ten years I never ran out of water and normally the water level is 4 feet below ground level. The area around the well had grown in bit, but of late I have been clearing out the trees that have moved in to shade it.

I was going to build a platform to elevate the tank but my town is very aggressive at taxing structures so I decided to build it out of firewood. Its all beech that I slabbed with my log splitter so the pile is pretty solid. The tank is distorting when full but the price was right. I have a DC bilge pump hung offa PVC pipe that sits down in the well several feet. The pipe goes through an elbow that sits on edge of the well opening and then runs to the top of the tank. Bilge pumps are not rated for much pressure so my 500 GPH rated pump is probably putting out 50 GPH. One 50 watt panel will drive it at this low flow but I paralleled in a second panel to deal with sun angle. There is a submersible float switch hanging upside down in the top of the tank. When the tank fills up the float switch opens (opposite of a boat bilge) and the pump shuts down.

I normally water the garden with a soaker hose, unfortunately soaker hoses are rated for higher pressure. I left one 25 foot soaker hose running overnight and the tank only went down about 2 feet. The ground was not damp so I need more flow. There are soaker hoses made for rain barrels so I ordered one on Amazon. I was out working wood yesterday and hooked up a cheap lawn sprinkler. The sprays only reached about 5 feet from the sprinkler but its did soak things well. From about 8 to noon the tank did go down gradually. I shut down around 1 PM and the tank refilled by 4 PM.

The plan is to match the soaker hose to tank and see if I can just leave it running 24/7. On cloudy days there should be less demand for water. Worst case is a battery operated timer.

I did notice that with hot weather and extra water my strawberries are real happy. Considering there was plowable snow two weeks ago its nice to see the garden waking up.

Note this is proof of concept. I need to replace the temporary wiring with UV resistant outdoor wiring, make a mount for the panels and clean up the wiring runs.

P5260259.JPG P5260258.JPG
 
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peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
Worst case I will get a small diameter drill and poke a few holes.
 

peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
Well the new rain barrel hose showed up, its similar to my standard hoses but has a purple stripe on it and a strainer in the inlet connector. I hooked it up last evening and threaded it under my garden mat (woven poly fabric with holes for plants in it to keep the weeds down). It definitely puts out more water than my old hose. It didn't get a full test as it rained over the night but the level in my tank definitely dropped at a higher rate than with my other standard soaker hose.

I am hoping that my application is a better fit then a rain barrel. Unlike a rain barrel typically fed from a roof, I am pulling clean well water into a mostly sealed tank. A rain barrel is a poor mans cistern but its missing a very important component which is a roof washer. This device diverts the first few minutes of rain on the roof away from the cistern so that the contaminants on the roof do not make it to the tank. My guess is without one, the pores of the hose would quickly fill up even with a strainer. It also potentially introduces bacteria so that scum could form in the tubing's pores. There also will be an eventual buildup of grit from a roof (if its asphalt shingles).

In my case the water in the well is filtered by the ground so it should be relatively free of contaminants to plug up the hose. I may still have a problem as I did have some rusty slime that could form in my water lines if they were not used but I will keep an eye out on the hoses effectiveness on keeping the plants watered.

Definitely still an experiment in progress but my three everbearing strawberry plants that survived the winter are loaded with blossoms and have set a few green berries less than 2.5 weeks after the last plowable snow.
 

MikeK

Member
Oct 12, 2014
28
MN
I have had a plastic tank kicking around around for several years that a friend dropped off. It used to hold wood glue but has been rinsed out a few times including an acid/alkaline wash so is fine for garden watering. When I first built my house it was in a new development and it took ten years for an uphill house to be built. I switched to a deep artesian well before the septic tank went in on the other side of the street. Despite being on a hill, there is a layer of hardpan clay about 2 to 4 feet deep. My surface water well coincidentally sets in a low spot of the hardpan and the bottom is about 15 feet deep. For ten years I never ran out of water and normally the water level is 4 feet below ground level. The area around the well had grown in bit, but of late I have been clearing out the trees that have moved in to shade it.

I was going to build a platform to elevate the tank but my town is very aggressive at taxing structures so I decided to build it out of firewood. Its all beech that I slabbed with my log splitter so the pile is pretty solid. The tank is distorting when full but the price was right. I have a DC bilge pump hung offa PVC pipe that sits down in the well several feet. The pipe goes through an elbow that sits on edge of the well opening and then runs to the top of the tank. Bilge pumps are not rated for much pressure so my 500 GPH rated pump is probably putting out 50 GPH. One 50 watt panel will drive it at this low flow but I paralleled in a second panel to deal with sun angle. There is a submersible float switch hanging upside down in the top of the tank. When the tank fills up the float switch opens (opposite of a boat bilge) and the pump shuts down.

I normally water the garden with a soaker hose, unfortunately soaker hoses are rated for higher pressure. I left one 25 foot soaker hose running overnight and the tank only went down about 2 feet. The ground was not damp so I need more flow. There are soaker hoses made for rain barrels so I ordered one on Amazon. I was out working wood yesterday and hooked up a cheap lawn sprinkler. The sprays only reached about 5 feet from the sprinkler but its did soak things well. From about 8 to noon the tank did go down gradually. I shut down around 1 PM and the tank refilled by 4 PM.

The plan is to match the soaker hose to tank and see if I can just leave it running 24/7. On cloudy days there should be less demand for water. Worst case is a battery operated timer.

I did notice that with hot weather and extra water my strawberries are real happy. Considering there was plowable snow two weeks ago its nice to see the garden waking up.

Note this is proof of concept. I need to replace the temporary wiring with UV resistant outdoor wiring, make a mount for the panels and clean up the wiring runs.

View attachment 260477 View attachment 260478
Peakbagger, I enjoy your posts.

I use a very similar set up for watering a few head of cows. I believe I read on hearth (may have been something you posted) about another forum with solar info. My pump is a little bigger and the reservoir for the cows is an IBC tote. It gravity feeds a smaller tank with a homemade float. I do run the pump with a 100 watt panel, I think the bilge pump is 750 gph. What I really like is not needing a battery or charge controller. If I remember right I read to size the pump/panel so that the max wattage of panel was about 150% of the pump so that the pump will start. I am uncertain if that matters for these little bilge pumps. This is the second summer it has been in use. This is a simple system that is more convenient than my previous pump system. (Also keeps the cows out of the pond, hopefully improving water quality and keeping them healthier.)
Another fun thing with this is that I have a TracFone that I can call on Skype and check the water without having to drive all the way out there.
 
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peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
An update, the rain barrel soaker hose has definitely plugged up a bit to the point where its too slow. The strainer on the inlet connector had minimal debris in it so whatever is plugging it is very fine, biological or just the material weathering. It still can flow more water than my prior soaker hoses but definitely not what I hoped for. I picked up a old fashioned whirly bird sprinkler that works pretty well which is a bit too generous and needs to be moved around the garden. Its probably overkill on watering and definitely will get ahead of the solar pump.

I also have float switch that sticks on occasion. I am using it upside down and sometime it get stuck in the off position. I have some hack fixes but for now I just need to thump the side of the tank and it releases.
 

begreen

Mooderator
Staff member
Nov 18, 2005
82,668
South Puget Sound, WA
I never had much luck with soaker hoses on low pressure systems. After a year they would plug up with biological matter (algae?). I switched to drip irrigation from Dripworks and that has been working for years.
 

peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
An update, all of NH is in drought conditions, the water level in the well has dropped as the trees leaf out and pull the water out of the ground. The bilge pump I was using ran out of elevation head. it was still submerged but just could not develop the lift to get it in my elevated tank. I temporarily moved the tank off its pedestal to the ground and the pump was able to move some water into it. I found an inline submersible that puts out up to 18 psi and mounted it lower in the well. It draws a max of 4.3 amps nameplate. My two panels put out around 6 amps so its a good fit. Knock on wood, this well never ran dry when I was using it for my house. I put the tank back up on the stack of wood and filled it about 3/4s in about 4 hours. The float switch is sticky and gets stuck when the tank is full but seems to be working a bit better. I still havent resolved the soaker hose issue so I move a whirlybird sprinkler around. I will probably try drilling the soaker hose at each plant once this heat breaks to turn it into drip system.
 
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peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
An update, all of NH is in drought conditions, the water level in the well has dropped as the trees leaf out and pull the water out of the ground. The bilge pump I was using ran out of elevation head. it was still submerged but just could not develop the lift to get it in my elevated tank. I temporarily moved the tank off its pedestal to the ground and the pump was able to move some water into it. I found an inline submersible that puts out up to 18 psi and mounted it lower in the well. It draws a max of 4.3 amps nameplate. My two panels put out around 6 amps so its a good fit. Knock on wood, this well never ran dry when I was using it for my house. I put the tank back up on the stack of wood and filled it about 3/4s in about 4 hours. The float switch is sticky and gets stuck when the tank is full but seems to be working a bit better. I still havent resolved the soaker hose issue so I move a whirlybird sprinkler around. I will probably try drilling the soaker hose at each plant once this heat breaks to turn it into drip system.
Looks like I am getting close, the new submersible pump is running well and putting out enough pressure to pump to the top of my tank while its sitting on its woodpile. I added a nut on the end of my float switch to get it so it would not stick. Its a bit less responsive to shutting the pump down before the tank overflows but seems to do it just short of a spill. I also got out a drill bit and drilled some holes in the soaker hose so there is a drip/spray at the major plants. I got heavy rain yesterday with more predicted until Thursday so the soaker hose is off but the added holes seems to have helped with the water volume delivery. I will keep the drill out and adjust as needed during the next dry stretch.

The two remaining items is rig up strainer for the pump and then mount the solar panels as right now they are just laying on top of the well.
 
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peakbagger

Minister of Fire
Jul 11, 2008
5,297
Northern NH
@peakbagger, what pump is your 18psi inline pump that replaced the bilge pump? Just curious, thanks again!
Rule IL280P 12 Volt 280 GPH Inline and Submersible Pump

I got the 14' waterproof extension cable option.
 
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