Drip Irrigation Basics, and My Honest Struggles With It
A confession up front, because I said it in my own notes and I meant it. Drip irrigation is not my strong suit. I can install a system fine. I've also rewired my own emitters wrong more than once and had a whole section of bed run bone dry for basically all of July before I noticed. So take this lesson as "here's how it works and here's where I've personally messed it up," not "here's the master telling you the secrets."
Why drip instead of sprinklers
We talked a few lessons back about watering deep and rare instead of shallow and often. Drip is the tool that actually lets you do that. A sprinkler head throws water up in the air where our dry air and elevation eat a chunk of it before it hits the ground. Drip puts the water right at the base of the plant, slow, so it soaks down instead of running off or evaporating. For xeriscape plants trying to send roots down deep looking for water, this matters a lot. You're not just saving water, you're training the plant to grow the roots you want.
The basic parts, plain language
A drip system for a home bed is really just four things.
The tubing. Half-inch black poly tubing is the main line. It snakes through your bed and everything else connects to it.
The emitters. Little plastic pieces that drip water out, right where you push them into the tubing next to a plant. You can get ones that put out a set number of gallons per hour, or adjustable ones you can turn up or down.
The pressure regulator and filter. These go right at the spigot, before any tubing. Don't skip these. Regular hose pressure will blow your drip system apart or clog the emitters with grit, and our hard water leaves mineral buildup that a filter catches before it gets downstream.
The timer. Battery-operated ones that thread onto the spigot work fine for most yards. This is the piece that makes the "deep and rare" thing happen, because you set it and it runs long enough, on the days you pick, without you standing there.
Laying it out at home
Start smaller than you think you need. Run your main line along the back of the bed, then branch smaller quarter-inch tubing out to each plant or cluster of plants. One emitter per plant if it's small, two on opposite sides of the root ball if it's bigger, so the water soaks the whole root zone instead of just one side.
Push the emitters in close to the trunk or stem but not right against it. And here's the mistake I make constantly: I get the layout done, turn it on, and don't actually watch it run for a full cycle. Twice now I've had an emitter pop loose or get plugged and not caught it for weeks, because I trusted it was working. Walk the line while it's running. Every time you install something new, watch the water actually come out where you think it's coming out.
Getting down there to check it
More telling on myself. Last spring I was setting flagstone in one of the beds, which meant getting down low to check the emitter lines running underneath, and I ended up on all fours trying to level things and see what was going on at ground level. Getting back up took me two tries and grabbing a fence post to haul myself upright. Didn't say a word to anybody, just quietly started keeping a five-gallon bucket out in the yard to sit on when I'm working low to the ground. I call it efficient. Marian calls it something else. Checking your drip lines means getting down at plant level, and if your knees are anything like mine, plan for that. A bucket, a garden stool, whatever works. No shame in it.
Where I still get it wrong
Two things trip me up every single time. One, emitters clog, especially with our hard water, and you don't always notice until the plant's stressed. I check mine at the start of each season now, run the system, and feel for water at every single emitter with my hand. Two, it's very easy to set the timer once and never touch it again. Your watering needs change through the season. What's right in May is way too much in September. I've genuinely had a section run dry for most of a summer because I set the timer in April and just trusted it. Don't trust it. Check it monthly at least.
A caution worth saying plainly: if you're cutting into the main line to add a branch, shut the water off at the spigot first. Poly tubing under pressure will spray you and whatever's nearby, including you, right in the face if you're not careful.
Before next time
If you've got sprinklers on a xeriscape bed right now, go stand there while they run once this week and watch how much water actually lands where the plant needs it versus where it doesn't. That's the whole assignment. You'll see the problem before I even have to explain it.