This is a collection of thoughts about what we have done right in installing our irrigation system, and what we probably should have done differently.
Our system is simple and small by modern standards, about 1,000 feet of PVC pipe running in trenches to eight faucets, one outdoor sink, and three drip irrigation stations, and all within about 500 feet of each other. It is daunting for us, however, and the project has continued for a couple of weeks. Here’s what we’ve learned so far.
Do the hand digging before you rent the trencher. Once you open a trench, you don’t want it to stay open any longer than absolutely necessary. We should have done the hand digging necessary to join the existing plumbing system before opening the trenches, so we could have started immediately laying pipe after the trenches were open. Instead, we lost 3-4 crucial days of dry weather while we did the hand-digging and connecting. This was the first time I had ever glued PVC, so I really needed to learn on the simple jobs like running 3/4″ pipe to a faucet. Now that I am familiar with how to glue PVC, I would go ahead and cut into the existing system and cap off the connection so I could avoid having to do that with the trenches open.
Use a trencher with hydraulic steering. We paid $40 extra to rent the trencher that has hydraulic steering, in our case a Vermeer RT200 from Southern Rental in Auburn. The less expensive model would have required that we “muscle” the trencher when we needed it to change directions. I can’t speak for the less expensive model, because I’ve never used it. What I can tell you is that the RT200 was simple to operate and negotiated the many gradual turns we knew we needed without breaking a sweat. See Trenching for Drip Irrigation for more info.
Go ahead; add that extra faucet. Once you’re renting a trencher, the extra cost of running a few extra feet and adding another faucet is small. This is a good time to plan not just for what you need now but for what you think you might need later, and go ahead and prepare for it.
Don’t go crazy with cut-offs. We thought we would need cut-off valves here, there, and everywhere, but in planning we realized we wouldn’t. On those rare occasions when we need to work on the system, it’s really not that disruptive to turn off half the system to work on it. We ended up returning about half the cut-off valves we had thought we would need.
Do you really need a bucket full of spare fittings? My brother is a big believer in keeping one or two of the fittings for his irrigation system on hand so he can get to them quickly in a pinch. That’s probably the right approach for him, because the nearest hardware store is 45 minutes away. By contrast, we’re close to Tallassee, so I’m less than 10 minutes away from True Value, where they have all the fittings I think I’m likely to need. I’ll let them maintain that inventory, and I’ll keep that bucket empty.
And speaking of inventory . . . I let the salesman at the drip irrigation place I used talk me into buying 1 1/2″ pipe, on the grounds that 1 1/4″ (which we agreed would be adequate for our application) wasn’t standard and that fittings might be harder to find. Turns out it’s just the opposite in my neck of the woods. 1 1/4″ is “standard” around here, and 1 1/2″ is the unusual size. You can get it, but it’s more costly and there are fewer fittings available, so you sometimes end up needing to use three fittings instead of two, or one. The lesson I draw from this is that I should have found out what was standard or common in my area before shopping for drip irrigation parts, so when the salesman tried to tell me what was standard I could have said maybe in your area, but not here. I now have a system that uses 1 1/4″ (because that’s the size of the pre-existing pipe), 1 1/2″ pipe for the main lines, and 3/4″ pipe for all the faucets and some of the drip. That’s just the kind of fragmentation I was hoping to avoid. It’s not deadly, but it will make repairs and expansions later on a tad trickier.
But by all means do it. We’re already reaping the benefits of our system, and we don’t even have the drip stations working yet. We were using hoses to reach everything, and it was about to wear us out just dragging hoses all over the place. If you’re trying to grow things and don’t live in the jungle, you will be happy you have spent the time (and let’s be honest, an amount of money that’s not trivial) to have a truly functional and flexible irrigation system.