Automatic Watering System for My DIY Greenhouse

Welcome back to my DIY Greenhouse! Today, I'm going to show you how we set up a greenhouse irrigation system to automatically water ALL our plants with just the turn of one tap. This was a first-of-its-kind DIY for me, and I can't wait to show you how we did it! 

How do you water plants in a greenhouse?

When making our decision about how to get enough water to our plants on a regular basis, we knew we had a few options to choose from. 

One option was attaching a garden hose to the main water line tap and using it to water our plants by hand whenever we felt they needed it. This was probably the easiest option, but also the least elegant one! I didn't want to drag an ugly hose in and out every time I watered plants. Plus, we are on a well and I didn't want to waste too much water with whatever system we chose. 

Another option was installing a rain barrel and water catching system on the side of the greenhouse. This would have meant setting up eavestroughs, which I didn't want to do. I also thought about installing some other type of water storage tank close by. This method would have created less water waste, but just like the hose, I would have had to water by hand every time and that didn't feel sustainable for our busy lifestyle. 

So, after doing some thinking I decided the best option would be to create a DIY irrigation system to water my plants automatically, using the least amount of water possible to get the job done. 

Which irrigation method is best for greenhouse?

Once I decided that automatic watering was the way to go, I still had to make a decision about how to do it! There are many options out there and the only way to pick one is to figure out what works best for you and your greenhouse. 

I knew that capillary matting wouldn't work for me, since I didn't want to make room for a water reservoir on each bench or shelf. I think this method works best for propagating seeds and tiny plants. Since I already did this in my kitchen over the winter (it's a second greenhouse in there, you guys), I knew I needed a different method. 

Overhead sprinklers are another popular option, but I read somewhere that getting your leaves wet constantly can lead to a greater chance of disease and injury for certain plants, so I wanted to make sure my system allowed for root watering as well. Plus, sprinkler systems seemed like a wasteful, messy way to water plants. 

So, I decided that a simple drip system would be the best way to water my plants. This was brand new territory for me, as I had never done a plumbing or irrigation DIY of any kind. How hard could it be, right? 

Getting ready to install

Once I decided on a drip nozzle system, I went shopping on Amazon and got an incredibly reasonably priced set of hoses and adjustable drippers for around $50! Included in my micro drip irrigation system kit: 

• Large hose that connects to the main water line 

• Smaller drip lines that run off the large hose

• A set of nozzles that will connect to the smaller drip lines. These can either drip or mist water, depending on your preference

• A set of stake-like emitters to put right in your planter (they direct water right at the roots of your plants) 

• Large connector pieces to run the smaller hose off the large one

• Small connector pieces to attach the nozzles or stakes to the smaller hose

CHECK IT OUT:

CAD: https://amzn.to/4ahf7wd USD: https://amzn.to/4aiway3

The first thing I needed to do for my new system was run the large hose from the water tap to the inside of the greenhouse. I didn't want the hose running through the door, so I had to drill a hole near the bottom of the outside wall closest to the tap. I used my impact with a spade bit to drill a hole the right size. Then, I drilled another hole (using the same bit) in the bench that runs along that side of the greenhouse so the hose could run up the side of the wall and across to the shelves above. 

Installing my DIY irrigation system

I took the large hose out of its packaging and inserted one end through the hole at the bottom of the wall of the greenhouse, leaving the bulk of the hose on the inside. I went outside to attach the threaded end that would allow this hose to screw on to the main water hose and turn the flow on and off, and then I went back to tackle the inside.

I threaded the large hose up through the hole I made in the bench. I then used metal holders and some screws to attach it to the greenhouse frame so it would stay in place against the wall (depending on what you are attaching your hose to, zip ties would work too). I ran the hose up the wall to the underside of the first shelf. Once I got it to the right height and wanted to add the smaller drip line, I cut the mainline tubing with a pair of heavy scissors. 

Then, I added a connector piece that allows 4 strands of drip line to go in 4 different directions. Next I put another length of the large hose on the other end of the connector and continued installing it, this time using the metal holders to attach the tubing to the underside of the shelf. I continued running this main hose, cutting it at direction-changing junctions and attaching it to shelves or the greenhouse frame, until I had the first half of the greenhouse finished. 

Next, it was time to add the small lines to the connector pieces. I attached one end to the connector, then I cut the tube to the appropriate length and added the nozzle or stake to the other end of it. Some of these lines I made very short and attached to the shelf with a metal holder. Some of them I left long, and I even ran some of them up through the shelves themselves (after drilling more holes) to water areas farther away from the connector. You might be able to create more regular intervals than I did. Just make sure you plan before you cut! 

Time to do a test

When I reached the halfway mark, I didn't want to go any further before I did a test run. I didn't know the range and potential flow rates of these nozzles and stakes and I wanted to see if my system worked before I finished the whole thing. I wanted to know two things: 

1. How far the reach of the spray from each nozzle would be 

2. How far the reach of each stake would be (How many would I need for my vegetable garden in the tub?) 

It was a bit nerve-wracking, but the only way to see if my plan was working was to turn the water on. 

I turned it on...and nothing bad happened! The nozzles and the stakes behaved exactly the way they should. The stakes were almost like little sprinkler heads when they were at full power (you can turn the flow up or down) and would work perfectly in the tub to create a little umbrella of water close to the ground. The nozzles had an impressive range too. Before the test I was worried about the water pressure with so many lines, but the pressure was just fine. 

Keep on installing 

Now that I knew my plan was working, I went ahead and installed tubing around the rest of the greenhouse. The process was the same: 

1. Run the main hose, attaching it to the greenhouse frame or shelves and making connector junctions as necessary 

2. Cut the drip lines and attach them to the connectors 

3. Attach the nozzles or stakes to the ends of the drip lines and secure them in place

I made a few adjustments during the second half of the installation process. I made two very long drip lines with the stake emitters on the ends and left them free and unsecured. I did this so I could use them to water the tomato plants I want to grow under the bench on the floor. I made these lines long so that I have freedom to place these pots wherever I want. I also made some longer lines with emitter stakes for the tub, which were also free and unsecured. So, not all the lines in the second half of the greenhouse were neatly secured to the walls or to shelves. 

Here is the basic layout of my irrigation system (in case it helps you):

1. Drip lines with nozzles secured to the underside of the upper shelf to mist the plants underneath

2. A few drip lines that I ran to the top of the shelf and attached stakes to. These will be put inside the pots that will be sitting on the shelf 

So, some plants will be watered from above and some will be watered at the roots.  

This is one of those time-consuming, tedious tasks that you just have to push through. I knew putting in a proper irrigation system would save me a lot of time and water in the long run, so I stuck with it! And I'm so glad I did. When I turned the water on after the second half of the greenhouse had been plumbed in, it brought me so much joy to see the water flowing. And all I had to do was turn one tap and walk away! 

Final thoughts 

I am so happy with how this irrigation system turned out! One of my fears at the start of this project was that once I had all the lines installed, I wouldn't be able to change the layout of where I grew my plants. But as I went along I realized that adding more lines would be so easy! All you'd have to do is cut the line where you need to, add a connector, and then add more drip lines and nozzles or stakes. Of course, you need to be careful not to add TOO many because of how that would affect the water pressure. But a few more would be fine for my system. Plus, any lines I decide not to use anymore can actually be turned off, which means my ability to add and subtract lines is almost limitless. 

This was a surprisingly straightforward DIY! I am feeling confident that my irrigation system will work and that I can change it if I ever need to. 

Is this the end of our greenhouse adventure together? Probably not! Thanks for following along and being part of this awesome community. 

See you next time!