Want to build a watering system that is fully off grid and autonomous?
Want to save on water usage and cut down on electrical consumption?
Looking to invest now to save time and money in the future?
Then a solar powered drip irrigation system is a great choice for your garden!
Solar irrigation systems combine two resource saving systems into to one: energy and water.
You may have noticed through your research that there are not out-of-the-box systems that combine both a solar powered water pump with drip irrigation systems. I found this out too and have developed my own system that works really well and is completely DIY.
By the end of this tutorial, you will learn how to setup up a drip irrigation, how to power a water pump with solar, and then combine the two for a completely autonomous watering system.
I have divided this article into two sections: Phase One – building the drip irrigation system and Phase Two – building the solar power water pump.
Let’s dive right in!
Table of Contents
- Calculating drippers by soil type
- Calculating GPH drip irrigation flow
- Calculating the diameter of mainline tubing
Phase One: Building the Drip Irrigation System
For the sake of simplicity in this tutorial, I will be using a basic square vegetable garden as an example.
Step 1: plan your drip irrigation design layout.
Propper planning prevents poor performance! You don’t want to haphazardly construct your system only to find points of failure down the road.
Making a sketch of your garden will help you engineer the right layout and could help you see problem points that you wouldn’t have otherwise noticed. Take note of dimensions and unmovable structures and objects.
Notes for designing your drip irrigation system
- Where your water source is located and if there are any obstacles along the way
- The distances you will need to run your irrigation tubing
- Designing your system without crossing over walkways or burying the pipe under walkways
- Utilizing spaces along paths to grow vegetables and herbs (a permaculture philosophy)
- Laying out your system to use the least amount of pipe and tube for efficiency
- different gardening zones may require different amounts of water (a more complex form of drip irrigation)
If you are still in the design phase of planning your garden, take a look at my Guide to Permaculture Farming for some interesting principles you can apply.
Drip Irrigation System Diagram
This particular drip irrigation system that I designed is more complex than just running one mainline, but is fairly easy to execute as long as you measure and plan accordingly.
Step 2: Calculating drip irrigation formulas
There are some calculations that need to be made when planning out your drip irrigation system. Luckily, the calculations are quite simple and don’t take but a minute or two to figure out.
Calculating drippers by soil type
The first calculation you need to make is to determine what soil type you have to get the proper gallons per hour (GPH) flow rate:
Clay – .5 GPH drippers
Regular soil – 1 GPH drippers
Sandy soil – 2 GPH drippers
*Note that you can purchase adjustable drippers up to 20 GPH for large bushes and trees.
Calculating GPH drip irrigation flow
Now that you have selected your soil type, you can calculate your Gallons Per Hour flow to your drip irrigation system.
X amount of drippers * GPH of drippers = Total GPH usage
For our example, if you have 75 drippers (1 per plant), multiply 75 by the GPH of the dripper (1 GPH) and your total GPH flow rate is 75 GPH.
Calculating the diameter of mainline tubing
Now that you know your GPH usage, you can select the correct mainline tubing.
The most commonly found sizing for mainline tubing is 1/2 inch which should take care of most household gardening setups.
With this knowledge, we can select the .50 inch tubing as the correct size mainline for our garden. We can run branches of tubing as shown on my diagram in the .25 inch size, you will need a 1/2″ to 1/4″ fitting.
Make sure not to surpass the maximum GPH of the tubing which will be listed on the manufacturer’s instructions and do not overextend the tubing past its maximum run length.
Step 3: Gather drip irrigation components
I’d like to start off by noting that many components for drip irrigation systems are measured in the metric system. There are labeled conversions that are not entirely correct which can cause your system to fail.
It is recommended that instead of trying to convert from metric to imperial (15mm and 16mm are both labeled as ½ inch!) stick to the metric system.
Your fittings need to be precise. Even a millimeter off can blow your entire system over time. Plan accordingly.
You can always purchase a preassembled drip irrigation kit that will guarantee compatible components.
Option One: Buy a Drip Irrigation Kit
When it comes to drip irrigation, any mismatched components, even in the slightest of measurements, can become areas of weakness which will breakdown into leaks.
The nice thing about purchasing a drip irrigation kit is that you will be certain that all of your components match up.
I can tell you right now that the kits available on Amazon are complete garbage. They are cheap and flimsy – you get what you pay for – and I suggest steering clear from the cheap Chinese junk they sell.
Deluxe Drip Irrigation Kit for Small Farms
This is an excellent Drip Depot kit that accommodates 15 rows of plants. The kit includes 3/4″ Poly Tubing for mainline allowing higher flow rates and longer drip tape runs.
This is a complete, self-contained drip irrigation kit that comes with everything you need to create a working system. Check it out on Drip Depot!
Option Two: Purchase components individually
A bonus to piecing together your system is that you can make a custom build that matches to your garden’s exact specifications.
You can purchase the amount of tubing you need, have various emitters, and punch in your holes so you can perfect the spacing.
You can also piece together your own system if premade kits are not available.
Again, I highly recommend Drip Depot for creating your custom drip irrigation system. All of their components match so you don’t have to worry about fitting issues.
Drip tubing – this is a special tubing specifically designed for drip irrigation systems. It is a thin polyethylene tube that is much thinner than a standard hose. Drip tubing is meant for above ground use, do not bury the tubing underground, it will ruin it.
Drip irrigation emitters – these are the dripper devices that are installed along the tubing. Some tubes have them pre-installed, otherwise, these can be bought separately and installed onto the tubing. For manual install, you will need a hole puncher.
There are different varieties of drippers, the most common are standard drippers, bubblers, sprinklers, and sprayers. The spacing between the emitters will depend on the plant type you are growing and how your tubing is laid out. Anywhere from 6 to 24 inches between plants is typical.
Hole puncher – this is a must-have tool if your tubing does not have premade holes. This punches the holes into the tubing where you insert your dripper.
Irrigation backflow preventers – an essential piece to the setup, the backflow preventer keeps dirty garden water from flowing backward in the tubing. Backflow can contain contaminants that spread soil born disease. Do not skimp on this component!
Pressure regulator – this reduces the pressure to a consistent PSI level to not overload the system. If your water pressure is above 40 PSI then you will need a regulator. If your pressure is between 25 to 35, then you do not need one.
Filter – Your water might already be filtered but the tiny emitters can get clogged easily. Take the extra precaution and purchase an additional filter for your drip system. It may feel redundant but is worth the peace of mind knowing that your emitters will not get clogged up.
Hose connect adapter – this connects your water source to the mainline of the irrigation system.
End cap or hose end clamps – the end piece to cap off or clamp the end of the tubing and mainline.
Tubing stakes – keeps the tube from rolling around – which it will – if not fixated onto the ground.
Timer – a timer will allow for a completely autonomous system. If you are connecting to a water spigot, you can get a timer for the hose. You will need a different timer if you are connecting it to the water pump, which I will cover in the next section.
Fittings – includes couplings, elbow fittings, barbed tees, barbed connectors, tee fittings. All these components add options for a more complex system such as running multiple drip tubing lines from the mainline, connecting .25 inch line to .5 inch main line, creating branch lines, etc.
Goof plugs – to plug up holes in your tubing that are no longer needed or placed by mistake.
Once you have all your materials purchased and your design engineered, its time to install the system!
Step 4: Installing your drip irrigation system
As long as you have taken the time and planned out all your components and have measured everything correctly, a standard drip irrigation system shouldn’t take too much effort to install.
1. Start installation at the water source
This step will vary depending on whether you are plumbed in or running off an off grid water pump.
Install components in this order: Valve or pump, backflow preventer, pressure regulator, filter, tubing adapter, mainline tubing.
2. Layout all of your tubing and fittings
Start by connecting your .5 inch mainline tubing and then position all of your tubing that branches out from the mainline and adjust as necessary. If the tubing is too stiff, let it sit in the sun to warm up, which makes it more pliable.
Start to connect all of the pieces starting from the source down to the very end.
Once you have everything laid out and connected, cut the hoses at the end but do not clamp off just yet.
3. Install drip emitters
To manually install emitters, simply punch a hole into the tubing with a hole puncher, then press the emitter into the hole. Make sure that you have calculated your spacing correctly before you start punching holes. If you do mess up, don’t fret! That’s what the goof plugs are for.
Once you are done with the emitter installation, stake to the ground.
4. Flush the system thoroughly with water
Flush the system to remove any debris and then cap or clamp the tubing ends.
Run your finalized system for about an hour to see if any adjustments need to be made. Now enjoy the fruits of your labor!
Phase 2: Building a solar powered irrigation pump
In this section, I will go over all the steps and components to successfully build a DIY solar powered irrigation pump. This is a great choice for off grid watering systems!
There are many ways to get solar power to a pump; the goal is to make the system as simple and independent as possible.
I will be focusing on the simplest, most direct use of a solar panel to get the results we want.
How does a solar powered water pump work?
A solar powered water pump works by attaching a solar panel to the pump in order to give it power. The pump then draws from the water source and pushes it through the drip irrigation system.
The pump will run indefinitely while power is being delivered to it, which is why it’s important to install a timer to the pump. It is also important to install a battery to the pump for days where the solar panel is not providing enough energy to keep the system going, usually during overcast and cold days.
Option 1: Purchase a solar powered water pump kit
There are some decent solar powered water pump kits out there, but there are very few that are specifically built for a drip irrigation system. Most are built for fountains which could be retrofitted for drip systems but it’s probably not worth the hassle to do so.
It’s even harder to find a solar powered water pump kit with a battery backup included.
Since the kits are cheaper than piecing together the components individually, I have found that the components in these kits tend to be cheap and flimsy.
I did find one kit available at a decent price that could do the job. It’s a submersible pump with 50 watt solar panels. Still, it does not come with a battery backup.
Option 2: Building a DIY solar powered irrigation pump
Although it will cost you some more money and time to purchase and assemble the components, building a diy solar powered water pump system will be superior to any kit that is available at this point in time.
You can fine tune your components to match your exact needs and the components can range from cheap to robust, depending on how much you want to spend on your system.
Another advantage of setting up your own solar powered water pump is that if a component does go out, you can easily replace each one.
Overall, I recommend building your own system.
Steps to Building a DIY Solar Powered Irrigation Pump
The key to success is to prepare all of your calculations and components before you assemble and power up your system. Solar power systems are not all that complicated but you need to make sure all of your components will be compatible or else you could damage your system.
Let’s get started!
Essential Components for a solar powered irrigation pump
Solar panel – harnesses energy from the sun to run the pump.
Stand for solar panel – so it’s not just laying on the ground.
Solar charge controller – Keeps the connected battery powered and charged. It also makes sure that the battery doesn’t get overfilled or run dry, prolonging the life of your battery. This is an essential component for your solar power setup. Don’t worry, these are not that expensive.
To figure out what size controller you need, take the output watts of the solar panel and divide it by the volts of your battery. This will figure out the amps calculation for controller sizing.
100 watts / 12v = 8.33 amps
Being that we are only using one solar panel, we can get away with a super cheap charge controller.
Battery – keeps the system running in times of limited sunlight.
Cables – connects all the components together.
Water Pump Timer – Switches the pump on and off for an autonomous watering system. Make sure to match the correct voltage.
Water Pump – in this tutorial, I am using an above ground water pump, but this will also work for a submersible pump with some minor adjustments.
Step 1: Choosing the correct size water pump
1. We need to figure out how much water we are going to need for our drip irrigation system (calculated in the first section of this article) and then purchase the correct size water pump.
Too little water flow and we will not have enough water to run the system. Too much water flow and we could overload the system, causing damage.
In our example, we need 75 gallons per hour flowing through our system. Most pumps measure in gallons per minute, so we divide 75 gallons by 60 minutes to get 1.25 gallons per minute.
Try to match up the flow rate of your pump as closely as you can to the GPH of the drip irrigation system.
You may not find the exact pump for your calculation, but either err on the side of less GPM as opposed to higher GPM. You can also add a few more (or less) drippers to match up better to the flow of your pump.
2. we need to consider the PSI that your system needs. Drip irrigation systems need 15-30 PSI.
3. If your pump is having to move water to a higher ground, you need to consider the elevation change. Suction lift needs to be calculated in for loss of pressure.
4. You will also need to consider friction loss for larger drip irrigation systems. Most manufacturers will have a friction loss chart available.
For more information about selecting the proper pump, I suggest reading this very thorough, yet easy to follow, pump selection and calculation guide by Drip Depot: https://help.dripdepot.com/support/solutions/articles/11000061728-water-pump-buying-guide.
Step 2: Choosing the correct size solar panel
We need to figure out how many watts are needed to appropriately size the solar panel. If wattage is unknown, you can calculate it with a simple equation by using the voltage output and amps.
Volts times Amps = Power in Watts
For our example, we are using a 12 Volt DC 7.5 amp water pump. So our calculation is:
12 Volts x 7.5 Amps = 90 Watts per hour
For our pump, a 100-watt solar panel will provide enough electricity plus a little extra to keep the battery charged while the pump is running.
However, since our pump will not be running 24/7, we can downgrade the size of the solar panel and rely on the battery backup to run the pump for an hour or two, and then while the pump is off, the solar panel will charge the battery. In this case, we can choose the commonly sized 50-watt solar panel.
Note that our pump is a DC pump, so we do not need a power inverter to power the pump as the power supplied by solar panels is also DC.
Step 3: Choosing the correct size battery
We want to make sure that we select a battery with enough capacity to run the pump if the solar panel is operating at zero capacity.
Let’s stick with the 100 watt solar panel for our example.
100 watts is the amount that the solar panel will produce per hour.
The average amount of power a solar panel can collect per day is typically 500 watts based on being in full sun for 5 hours.
While the battery is charging, there are some power losses of about 15%. So our 500 watts will probably be more along the lines of 425 watts.
Battery capacity is expressed in Amp hours (Ah).
We know that we need a 12 volt battery for our pump.
We multiply our battery Amp hours (Ah) by the voltage:
Ah * Volts = Watts by the hour
So if we have a 35Ah 12V battery we simply multiply the two 35 * 12 = 420 Wh which will store most of the output of our solar panel.
Now, our pump will only be running for 2 hours out of the day. We need 90 watts per hour, so our system will only require 180 watts. Therefore, a 35Ah battery will give us a bit more than 2 days runtime without having to be charged.
Step 4: Connecting the solar power components in correct order
Before proceeding, make sure your solar panel is not in the sun. You can place a piece of cardboard over the panel to ensure there is no electricity running through it.
The first step is to hookup the charge controller to the battery with stranded copper wire. Make sure not to cross-connect the + and -.
The second step is to connect your timer to the battery. I suggest using the negative cable as it’s not hot. Splice in the timer on the negative cable. A battery-powered timer is ideal if you don’t want to mess with wiring power to the timer.
The third step is to connect the pump to the timer and the battery.
The fourth and final step is to hook up the solar panel to the charge controller with the appropriate solar panel connector cables, which are usually included with the solar panel.
Make sure not to cross-connect the + and – MC4 connectors as this will damage your system.
Once all the components are connected, you can uncover the solar panel and the battery will start charging. The charge controller will inform you when it is full and regulate the battery to keep it in optimal charge.
I suggest giving the battery one good day of charging before running the pump.
Is drip irrigation worth it?
Before we delve into the design and construction of our watering system, you may be wondering why using a drip irrigation system is right for your garden in the first place.
After all, if your sprinkler system is working decently enough, why go through the hassle and expense of taking on a more complex garden watering system?
Before you decide that installing a drip irrigation system is worth it or not, take a look at the advantages and disadvantages first.
Advantages of drip irrigation
There are loads of advantages for installing a drip irrigation system over a sprinkler or hand watering system.
Water efficiency is superior in comparison to a sprinkler system. A drip irrigation system works by depositing the water directly onto the soil and into the plant. Hardly any of the water runs off as the system directly soaks the soil.
There is also very little evaporation, leaving the drip system to produce the least amount of water waste.
Nutrient loss is minimized as fertilizers do not run off the ground as opposed to hand or sprinkler methods. Therefore, less fertilizer needs to be used, by as much as 30%, which saves money and lessens groundwater contamination.
A drip system can be installed on any type of terrain, including hills and sandy lands, making more areas open to cultivation.
Arid, windy, and sandy environments that used to be barriers to cultivation can be utilized with a drip system.
A drip irrigation system makes desert farming possible
Yields can be increased drastically. A study done by the Directorate of Water Management Research found fruit yields to be 12% higher while using over 30% less water.
Weeds that grow around the crop are greatly reduced as the water and nutrients only go to the intended plant.
Operational costs are lower as the pressure needed is reduced; costs are driven even lower when combined with a solar power pump system.
Unusually shaped or hard to reach areas can be used for planting which is traditionally difficult to water. This could be by a twisting walkway or a narrow strip of yard along a driveway.
You can use a drip irrigation system for just about any farming method, including vertical farming. You can read about my vertical farming systems guide here.
Although there are many numerous advantages to drip systems, there are cons as well to consider.
Disadvantages of drip irrigation
As I have come to find out through all of my research, there are always downsides to any system, including systems that seem like a perfect solution. Drip irrigation is not perfect and does need to be evaluated for each unique gardening and farming situation.
There is a higher initial cost for starting a drip irrigation system. You can save money in the long run from saved resources, but be prepared to shell out a good buck or two upfront.
Drip systems are great for small scale farming, but on a larger scale, the cost to replace damaged and worn equipment from UV light and movement will require a recurring investment.
The little holes in the hoses can get clogged up, causing them to dysfunction. Filtered water is a must and regular flushing maintenance is required to keep the system running.
Although water distribution is much easier, figuring out how much water to use for each growing phase will require some observation and research.
The salinity of the soil can increase over time as the saturated wet soil evaporates and leaves the salt on top.
In most backyard gardens, small farms, growing in arid climates and on difficult terrains, a solar power drip irrigation makes plenty of sense.
Drip irrigation vs sprinkler irrigation
Still not sure if drip irrigation is worth it? I have made this handy comparison table so you can compare drip to sprinkler:
Overall, my consensus is that drip irrigation is the better watering choice for home gardens, hobby farms, and arid climates. You can utilize more spaces and soil types and will save money in the long run. Just be sure to maintain your system to get the maximum life out of the components.
What are the benefits of solar irrigation?
The main reason I love the concept of solar irrigation is the fact that you can build an autonomous energy saving off grid gardening watering system anywhere and in any climate.
When you add a solar power system to an irrigation system, you can virtually run that watering system anywhere, as long as you have a water source. This could be a spring, year-round creek, well, or pond.
Solar power components used to be expensive but have come down considerably in price and have become more effective.
Solar powered drip irrigation systems are an excellent choice for off grid gardens, remote farms, and any garden that may be too far from a convenient- power source.
There are two routes you can pursue when adding solar to your drip irrigation system. You can either purchase a solar powered water pump kit or build a diy solar powered water pump.
And there you have it! A complete solar powered drip irrigation system.
I hope you found this tutorial informative and easy to follow. If you have any questions or comments, please feel free to leave them below.