If you’ve been a reader of the blog for a while, you’ll know that last year’s garden was our first one after we bought her house. We turned a large section of our yard into five garden beds, which was enough work that we never got around to figuring out an efficient way to water everything. We installed a rain barrel that reduced the amount of city water we had to use. It also reduced the amount of walking we had to do, since the rain barrel was close to the garden beds, but we still largely relied on watering cans for the bulk of the watering. It certainly wasn’t the hardest thing ever, but it was quite time-consuming. It took between 45 minutes and an hour to water everything, which got tiring toward the end of summer. It also wasn’t the most efficient use of water, which would be spilled when carried.

We knew that this setup was unsustainable and needed to be improved for this year’s garden. Initially, the conversation was just about getting the water source (hose bib) closer to the garden, making it easier to maneuver the hose around the plants. That remains a long-term goal, but it would have still required us manually watering every plant. The best idea quickly became an irrigation system that allows the water to be directed to the right place, reducing water and time waste. There are kits available from companies such as Drip Depot, but they can get very expensive, with one that would fit our needs costing at least $200. That was more than we wanted to spend, considering it wasn’t customizable. Instead, I set out to design my own.

Designing an Irrigation System

I had two requirements for the irrigation system from the beginning: a standard garden hose needed to be attachable, and it needed to be customizable and adaptable if our layout or needs changed in the future. I was also hoping to be able to buy as many of the items locally as possible, which would help me to visualize things and test connections in person. But before choosing materials, I needed to plan how the water line would go through our garden beds.

Rigid or Flexible Line?

Every irrigation kit I’ve seen uses flexible tubing for all aspects of it, which probably works well if a garden is small or everything is confined and in close proximity. That wasn’t going to work for us. Most of the flexible tubing used in irrigation systems is 1/4 inch. This size of tube works very well within the beds where water needs to be precisely directed. Anything thicker than 1/4 inch would be difficult to have precision with. Additionally, 1/4-inch tube works because you don’t need to move a large volume of water once it’s already been transported into the garden bed. However, where irrigation kits fail and get too expensive, in my opinion, is getting the water to the individual beds.

You need a 1/2-inch tube to efficiently transport water from the hookup to the beds. Some irrigation kits include a section of 1/2-inch tube, but you’re stuck with a set amount of it that may not meet your needs. Kits with this size of tube in them also get very expensive. So, I decided to MacGyver my own setup and use items you can buy at a hardware store. I have some plumbing experience and felt confident that we could use PVC pipe to carry the water throughout the garden and to the individual beds. I also did some research before starting this project and learned that others have done something similar. I settled on 1/2-inch pipe rather than 3/4-inch pipe because 1/2 inch will carry enough water, and it’ll keep costs low. A 10-foot piece of 1/2-inch PVC costs around $6.70 at our local hardware store. It’s even cheaper at Lowe’s and Home Depot.

The Path

Our garden consists of three sections. The first section has four beds in a 2×2 layout with a walkway between them. There’s a second section of one bed to the back left of the first section. Finally, the third section is behind the garage and consists of one bed. Because of how far apart some of the beds are, there’s no way to run one continuous line. There wouldn’t be enough water pressure for the entire length, and it would lead to overwatering at the beginning and underwatering at the end. Instead, we will need to use shutoff valves to divert the water to the correct beds at a given time. At this point, I started to walk through the garden and sketch out the potential schematics. This is what I came up with:

Figuring out where shutoff valves and joints will go was the most difficult part of the design. The shutoffs are important for diverting the water to the appropriate beds since we will want to water the beds individually to ensure that they’re watered evenly. It means we’ll need a shutoff placed at each bed as well as between them. The one placed at each bed allows water to go into the bed. The valve between each bed prevents water from going too far and forces the water through the open valve. But the shutoff can’t be placed in the main section of PVC. Instead, there has to be a joint and a short section of pipe that leads into the garden bed. It’s in that short section of PVC where the shutoff has to go. The goal of our irrigation system is to place the PVC in the walkways. The PVC will connect to the flexible tubing at each garden bed. The tubing will route up and down the rows in the garden bed, allowing the water to be directed to the root system of each plant. With a rough plan in place, we hopped in our Subaru and headed to the hardware store.

Gathering the Supplies

The night before we went to the store, we took measurements to get a rough idea of how much PVC we would need. It was just short of 60 feet, but knowing that we’d need more for the length between the main section and the beds, we bought seven 10-foot pieces. Besides needing to carry these pieces around the store, this was the easy part. The difficult part was figuring out what pieces we needed and how many of each.

If you’ve never been in the plumbing/PVC section of a hardware store, you’d be shocked at how many joints, collars, connectors, and valves there are. And because they’re all white PVC, they largely look like each other. You have to make sure you’re looking at the right size of joint to confirm it fits the pipe you’re using. Then, you have to check that the connection type is correct. There are two: threaded and slip.

Getting the right connector type is important. Then you have to make sure you’re getting the right joint. There are t-joints, 3-way, 4-way, elbows, and many more. If you get the wrong one, your project likely won’t work. We both knew that gathering all the items was going to take a long time in the store and was likely to take multiple trips. Both proved to be true. Our first trip took about an hour. They had the PVC pipe and joints that we needed, but they didn’t have enough shutoff valves or any pieces that would connect the PVC to our garden hose or to the 1/4-inch irrigation tubing. After transporting the PVC pipes home, which was a funny scene (imagine a Subaru Forester with a section of white PVC hanging out the sunroof like a unicorn), we went to Ace Hardware in search of the remaining items. Ace really is the place with the helpful hardware folks. An employee helped me find the connectors we needed and, as a fellow gardener, was interested in this irrigation plan. Unfortunately, they didn’t have enough of the connectors, but she special ordered them, and they arrived on Monday. That was all well and good, though, because I didn’t have enough t-joints and forgot to grab a collar to connect two PVC sections together. In total, these were all the items we bought:

• 7 10-foot 1/2-inch PVC pipes. This is the basic Schedule C PVC.
• 8 t-joints (slip-on)
• 10 shutoff valves – Purchased on Amazon in a 10-pack. We only need 8 of them, but it was cheaper to buy in bulk.
• 7 1/2-inch x 1/4-inch nylon barbed hose fitting – These are the pieces that had to be special ordered. These allow us to connect the 1/2-inch PVC pipe to the 1/4-inch irrigation tubing. The barbed ends allow the tubing to connect without the need for a hose clamp.
• 7 1/2-inch x 1/2-inch connectors – One end is threaded; the other has a slip fitting. Because the barbed hose fitting is threaded on the 1/2-inch end, this piece is what allows the PVC pipe to connect to the barbed hose fitting.
• 1 4-way connector – This piece has a slip fitting on all four ends.
• 1 collar – This piece connects two full-length PVC pipes to each other where no joint is located.
• 2 hose adaptors – These allow us to connect our garden hoses to the system.
• 200-foot roll of 1/4-inch irrigation tube. This is flexible and doesn’t have holes in it. The holes will be drilled with a 1/16-inch drill bit on my drill press. We may need more of this.
• Stoppers for the irrigation tube. These will go into the ends of the tubing after it’s been routed through a garden bed. Doing so will create the pressure that forces the water through the holes in the tubing.
• We may also need some staples or clips to hold the tubing and pipe against the ground.

In total, we spent around $150 for everything, coming in quite a bit lower than the $200 it would have cost to buy a kit.

Building the System

Once you acquire all the components, putting the irrigation system together is as easy as building a K’Nex or Lego set. I laid out the pieces in the garden where I wanted them to go. If the sections of PVC needed to be shortened, I took measurements and cut them on my miter saw. After that, I attached the sections with the appropriate joints. I’m not using cement in this project because I want to be able to take this apart in the fall. It shouldn’t be an issue since the water pressure will be pretty low compared to a house’s plumbing system. The majority of the joints are made with pieces that only need to be slipped together rather than threaded. But for any pieces that were threaded, I used Teflon thread tape to ensure a sealed joint.

With all the pieces laid out and cut to length, it was easy to assemble everything. The structure for every section went like this: Main PVC Section + Joint (4-Way/T) + Small PVC Section + Shutoff Valve + Small PVC Section + Barbed Hose Fitting.

For the irrigation line, I’m drilling a hole every 6 inches, and at the time of writing this, I’ve drilled holes in roughly 5 feet of it. I don’t want to drill any more holes until I know how long each section needs to be.

Here’s the final product. We haven’t tested it yet or attached the irrigation tube to the system. I will write a follow-up post that goes over how well the system works.