I don’t have a water source at my community garden plot so this summer I’ve been experimenting with drip-irrigation contraptions. My favorite so far is one that uses a wine bottle, and I’m sharing instructions here in case you’re bored out of your mind during the Covid-19 lockdown. You probably have wine bottles, but if you don’t I also give tips on how to use soda bottles and buckets.
- Cut the bottom off the bottle. The above shows a 750-mL bottle but a 1.5-L works, too. I own a Creator’s bottle cutter kit (it’s fantastic) but there are videos showing other techniques.
- Drill a hole through the cork to accommodate 1/4″ tubing.
- Cut a length of 1/4″ drip irrigation tubing so that it is 1/2″ longer than the cork. Put a small piece of tape over the opening of one end.
- Put a few drops of outdoor glue into the hole. Gorilla Glue is nice because it tends to expand, filling gaps in the cork.
- Insert the taped-up end of tubing into hole, pushing until untaped part is flush. Take off tape (that was there to make sure it didn’t get filled with glue).
- Once glue is dry, insert cork into bottle so that the 1/2″ overhang is sticking out.
- Attach an adjustable valve to the tubing.
- Attach a 12″ (or so) length of 1/4″ tubing to the valve.
- Attach bottle to a 36″ stake (1×1″ wood, 1/2″ bamboo, or plastic-coated metal) using wire. Make it extremely snug so that when filled with water it won’t drift down.
- Crumple up some tulle (or flexible screening) to form a filter plug near cork. Tamp down using a long rod. This prevents hole and valve from clogging.
- Attach tulle (or flexible screening) to top with two rubbers bands. One rubber band is fine but the second is backup in case sunlight degrades one. The screening keeps out debris, but also prevents mosquitoes from ovipositing when valve is closed (and bottle is filled).
Here are some closeups:
Once done, situate the irrigator in your garden so that you can easily see the drip and adjust the valve without fighting foliage or stooping. This is why the instructions above call for a short length of tubing rather than something that fully extends into the soil near the plant (where you couldn’t see it). Evaporation from a falling drop of water is probably non-zero but I think the ability to see the drip rate is worth it.
When you water drop by drop, slowly, the soil has time to fully absorb the moisture. Drip irrigated plants thus need far less water, sometimes dramatically less. Another benefit is that water isn’t constantly splashed onto leaves, something that can distribute as well as activate pathogens. Some plants simply don’t like wet leaves (don’t judge). And many plants (such as tomatoes) also benefit from being constantly hydrated, something that is hard to accomplish with normal irrigation. Finally, plants tend to take up fertilizer better when it is slowly delivered.
Plastic bottle drip irrigator
If cutting bottles is not in your skill set, soda bottles work fine. The only major construction difference here is that you need to insert a drip-emitter coupler into a pre-drilled hole in the cap. But that’s easy — the coupler just snaps in and seals even if you skip the glue step. I’d also recommend using a 2-L soda bottle, however, instead of the 750-mL one shown below. Plus make the stake 36″, not 24″ (too short, I’ve found), and use something sturdier than what I’ve shown. Bottle can be attached to the stake with wire or (as I’ve done here) with zip ties.
The screen on the top is absolutely critical. If the emitter clogs while you’re away on vacation and the bottle fills with water, mosquitoes will move in. Mosquitoes can complete development in as little as five days.
I also recommend cramming in some flexible screening into the neck of the bottle as shown above for the wine-bottle version. Round dish scrubbers will work, too.
Bucket drip irrigator
If you want to deliver gallons of water to a plant, buckets are the way to go. Below is one I made from a florist bucket I scored from Trader Joe’s. I used a coupler, inserted as per instructions for the soda-bottle irrigator. A bucket with a lid would be much better because it could keep mosquitoes out and would reduce evaporation. Even better would be a bucket with a clear lid so that you can quickly gauge water level. Or a clear bucket (they make them!). Elevate the bucket with bricks or mound of dirt so that the lowest part of the bucket is still above the emitter so that gravity can do its thing. You can also use much larger buckets (e.g., 40-gallon ones) and then attach multiple drip emitters via splitters or crosses.
In addition to the top screen (again, an absolute must for excluding mosquitoes), I recommend some sort of internal filter to prevent emitter clogging. I opted for a piece of weed-block cloth attached to some Gorilla tape.
The big disadvantage with ground-based buckets is that you can’t easily see the dripping in action. This means that you have to stoop down to inspect each irrigator to make sure the emitter hasn’t clogged, something that happens regularly if you haven’t screened and filtered properly. I prefer the elevated, bottle-based devices because you can walk through a garden and visually see that everything is dripping at a nice rate.
Just a sampling of other people’s gravity drip systems.
- Do it yourself bucket drip irrigation
- Drip irrigation in a bucket
- About bucket irrigation
- Bucket drip irrigation
- Gravity drip irrigation
- 5 gallon water bucket, 5 days to drain gravity drip irrigation system
- Irrigation system for your garden
- 13 DIY options for a drip irrigation system to save you time and money
- DIY – 5 gallon bucket gravity drip irrigation system for trees or bigger plants tutorial (YouTube)
- Bucket irrigation for gardeners (YouTube)
- Simple gravity drip irrigation (YouTube)
Drip irrigation suppliers
Some hardware stores carry these supplies, but there are plenty of online distributors, too.