Easy DIY Overhead Sprinkler System For Greenhouse Irrigation

Greenhouse irrigation systems make maintaining your greenhouse a snap, saving you tons of time. In this post, I will show you exactly how to design and install your own DIY overhead greenhouse watering system.

I absolutely love having a backyard greenhouse. It’s been so much fun being able to extend the growing season in both the spring and the fall.

It really does make a huge difference in extending our short growing season here in Minnesota. And it has been a game changer for my vegetable garden!

But, since rainwater can’t get into the greenhouse, it can quickly become a huge chore to keep up on watering.

That is why it didn’t take long for me to realize that I needed to figure out how to water my greenhouse without having to constantly lug the hose out.

Our Overhead DIY Greenhouse Watering System

There are lots of different greenhouse irrigation systems out there for sale, but they are expensive. Plus, these water irrigation systems are usually designed to be used in commercial greenhouses, not a backyard greenhouse like ours.

So, my very handy husband came up with an idea for a simple greenhouse watering system DIY project. He designed and installed an overhead sprinkler system in my greenhouse to help make my life easier.

It was so easy. It only took him about 20 minutes to build and install it. Plus, for a DIY greenhouse watering system, was a pretty inexpensive. That was a huge added bonus!

Let me tell you, as far as greenhouse irrigation systems go, this is the easiest one you will find!

Greenhouse Irrigation Supplies Needed

• Mainline drip irrigation hose (1/2″ poly drip irrigation tubing)
• Full (360 degree) spray pattern shrub sprinkler heads
• 1/2″ poly insert pipe tee connectors
• 1″ long 1/2″ sprinkler head risers (you’ll need one riser per sprinkler head)
• Garden hose connector (1/2″ faucet hose fitting)
• Poly tubing end cap
• Pipe thread tape (optional, helps to create a better seal on the sprinkler head threads)
• Garden watering timer (if you want an automatic sprinkler system)
• Garden hose splitter (optional, comes in handy if you want to hook up another hose to the same spigot)
• PVC pipe cutting saw or a PVC cutting tool (for cutting the poly tubing)
• Zip ties or 1/2″ pipe straps
• Tape measure

DIY Greenhouse Irrigation Systems Design

It sounds complicated. But, it’s actually pretty easy to figure out a greenhouse irrigation design that works best for you.

Each sprinkler head sprays up to 15 feet. So, first you’ll need to measure the area of your greenhouse in order to figure out how many sprinkler heads you’ll need.

Keep in mind the corners of your greenhouse that are farthest away from the sprinkler heads will get less water, so make sure the spray from each of the sprinkler heads overlaps to ensure full coverage.

Closeup of greenhouse overhead irrigation heads working

Our overhead greenhouse irrigation system design is super simple, we decided we would simply run the mainline poly tubing down the center beam at the very top of the greenhouse.

My greenhouse is about 20′ long by 18′ wide. So we only needed three sprinkler heads spaced evenly down the center for total coverage.

If your greenhouse is bigger than mine, you may need to modify your greenhouse irrigation design slightly.

One idea is to install two sets of overhead greenhouse sprinklers on each side in a U shape, connecting them with 1/2″ poly elbow connectors.

Overhead Greenhouse Sprinkler System Installation Steps

Step 1: Figure out how many sprinkler heads you’ll need – I already touched on this, but as a reminder, the 360 degree shrub sprinkler heads we used spray up to 15 feet.

You want the spray from each of the heads to overlap to make sure there aren’t any areas of your greenhouse that don’t get watered.

We spaced our sprinkler heads about 6-7 feet apart to ensure plenty of overlap, but you could space them out a bit more than that if you want.

Greenhouse sprinkler heads and risers

Step 2: Cap one end of the tubing – It’s easiest to cap one end of the mainline poly tubing first using the poly tubing end cap before installing the sprinkler heads. Simply pop the end cap onto one end of the tubing and you’re done.

Installing end cap onto sprinkler system tubing

Step 3: Add the sprinkler heads to the tubing – To install the sprinkler heads, cut the tubing using the PVC cutting tool (you could use a PVC pipe cutting saw to cut it instead).

Cutting poly tubing for greenhouse sprinklers

Then insert the pipe tee connector into both ends of the tubing. Once that is secure, screw one of the sprinkler head risers into the tee connector, and then add a sprinkler head onto the top of the riser.

Installing riser for greenhouse irrigation sprinkler heads

Once that one is secure, measure the distance from this first sprinkler head to the spot where the next one will go. Then simply repeat these steps for the rest of the heads you’re installing along the poly tubing.

Installing greenhouse sprinkler heads on top of the riser

Step 4: Install the hose fitting onto the end of the tubing – Once you’re done installing all the sprinkler heads that you’ll need for your overhead sprinklers, you’re ready to install the final piece – the faucet hose fitting.

Installing hose fitting for DIY greenhouse sprinkler system

Measure how long you need or want the tubing on your overhead sprinkler system to be. Then, cut the tubing and attach the hose fitting onto the end.

Make sure you leave plenty of length on the tubing so it’s easy to attach it to your garden hose.

Step 5: Test your greenhouse irrigation system – Now that you have everything put together, be sure to test it out to make sure it’s all working with no leaks before installing it.

It’s much easier to fix any leaks while you can lay it down on the ground, rather than having to get up on a ladder in your greenhouse to try to fix the leaks overhead later.

Testing overhead sprinklers for greenhouse before installing

To test your system, simply screw the hose attachment onto your garden hose, and turn it on. If there aren’t any leaks, then you’re good to go.

Irrigation system for greenhouse hooked up to garden hose

If you find some leaks, many times you can easily fix them using pipe thread tape. Pipe thread tape helps to create a more snug fit and a better seal on the pipe threads, helping to prevent leaking.

Pipe thread tape helps sprinkler heads and risers fit tightly

Step 6: Install your overhead greenhouse sprinkler system – The frame of my greenhouse is made out of PVC pipes, which made it super easy to install my overhead sprinklers. We simply used zip ties to attach the poly tubing to the greenhouse frame.

Easy overhead greenhouse sprinkler installation using zip ties

If your greenhouse is made out of wood, you can use 1/2″ pipe straps to attach your greenhouse irrigation system to the frame.

That’s it, I told you it was easy! Done and done!

Running our overhead greenhouse sprinklers

Easy Greenhouse Self-Watering System

Now that your very own DIY greenhouse irrigation system’s installed, why not take it one step further and turn it into an automatic irrigation system?

It’s super easy with a basic garden watering timer! Once we had everything installed in the greenhouse, I simply plugged the garden hose into the timer, set it, and forget it.

If you want to use the spigot for more than one hose, you can use a simple garden hose splitter.

My automatic greenhouse irrigation systems timer

After setting up your greenhouse irrigation system timer, I recommend checking on your greenhouse regularly to make sure everything is getting enough water.

You may find that you need to adjust the timer after a few days of running your automatic sprinklers, or as your plants start to grow larger.

Our DIY overhead sprinkler system for greenhouse irrigation

Once your greenhouse irrigation system’s hooked up to an automatic irrigation timer, watering the greenhouse becomes a totally hands-off chore.

And life becomes Oh. So. Much. Easier! One less thing to do, woohoo!

Ahhh, much better than having to lug out the garden sprinkler, and move it around several times for full coverage.

Commercial greenhouse watering systems are crazy expensive to buy, and watering the greenhouse manually is a total pain in the booty.

This DIY sprinkler system is easy to install, plus it’s very lightweight, and doesn’t weigh down the greenhouse at all.

Our inexpensive DIY greenhouse overhead watering system has really saved the day, and it’s made my greenhouse even more awesome!

More Cold Season Gardening Posts

• 17 Winter Interest Plants For Your Garden
• Beginner’s Guide To Cold Frame Gardening
• 7 Tips For Protecting Plants From Snow Damage

Do you have experience with any greenhouse irrigation systems in your own backyard? Share your tips and ideas in the comments section below. 

Print The Instructions

Easy DIY Overhead Greenhouse Sprinkler System

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This DIY greenhouse sprinkler system is easy to make in only a couple of hours, and requires minimal tools.

Materials

• Mainline drip irrigation hose (1/2″ poly drip irrigation tubing)
• Full (360 degree) spray pattern shrub sprinkler heads
• 1/2" poly insert pipe tee connectors
• 1" long 1/2" sprinkler head risers (you'll need one riser per sprinkler head)
• Garden hose connector (1/2″ faucet hose fitting)
• Poly tubing end cap
• Pipe thread tape (optional, helps to create a better seal on the sprinkler head threads)
• Garden watering timer (optional, needed to automate your watering system)
• Garden hose splitter (optional, comes in handy if you want to hook up another hose to the same spigot)
• Zip ties or 1/2" pipe straps

Tools

• PVC pipe cutting saw or a PVC cutting tool (for cutting the poly tubing)
• Tape measure

Instructions

1. Figure out how many heads you'll need - The spray from each of the heads should overlap to ensure all areas of the greenhouse get watered. The sprinkler heads we used spray up to 15 feet in a 360 circle.
   
   So we spaced them about 6-7 feet apart to ensure plenty of overlap, but you could space them out a bit more than that if you want.
2. Cap one end of the tubing - It's easiest to cap one end of the mainline poly tubing first using the end cap before installing the sprinkler heads. To do this, simply pop the cap onto one end of the tubing.
3. Add the sprinkler heads - Cut the tubing using the PVC cutting tool, or use a PVC saw.
   
   Insert the pipe tee connector into both ends of the tubing. Screw one of the sprinkler risers into the tee connector. Then add a sprinkler head onto the top of the riser.
   
   Once that one is secure, measure the distance from this first head to the spot where the next one will go. Then repeat these steps to install the remaining heads along the length of the poly tubing.
4. Install the hose fitting - Measure how long you need the tubing, then cut it to that length, and attach the the faucet hose fitting to the end.
   
   Make sure you leave plenty of length on the tubing so it's easy to attach it to your garden hose.
5. Test your system - Simply screw the hose attachment onto your garden hose, and turn it on.
   
   If you find some leaks, many times you can easily fix them with pipe thread tape. Simply remove the leaky head, wrap some tape onto the riser, and reattach the head over the tape.
6. Install your sprinkler system - If your greenhouse is made out of some type of piping (ours is made out of PVC pipes), then you can simply use zip ties to attach the poly tubing to the frame.
   
   If yours is made out of wood, then use 1/2" pipe straps to attach your irrigation system to the frame.

Notes

Make sure to test the sprinkler system for any leaks before installing it in your greenhouse. It's much easier to fix leaks while the system is laying on the ground than it will be once it's hanging overhead.