Introduction: Automatic Plant Watering Device (simple Version)

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This Instructable will teach you how to simply make an automatic plant water-er. Perfect for when you're going on vacation or when you just don't remember to water your plants. It will provide a specific dose of water on whatever schedule you set to one plant.

I made this to keep my pot of dragon trees tree alive while I was out of town for 5 weeks. It's a bunch of big trees in a small pot so they need to be watered pretty often and I didn't feel like calling in friend favors to stop by every other day for more than a month. Those gel packs, plastic bags, 2 liter bottles, plant wicks, etc wouldn't work because they don't hold or move enough water. (The tree goes through about a cup and a half of water a day.) And commercial timed pumps things were expensive. It worked so well I've kept using it even when I'm not on vacation. It's been working perfectly every day for two years. As long as I remember to fill it up once a month.

It's not the cheapest solution, but it's a lot cheaper than the commercial versions I found (and those even looked a little cheap to me). Some would have required me to have a running hose in my house for the whole time I was on vacation, which sounds like an invitation to a flooded house to me. This one costs much less (You can do it for less than $30 depending on what parts you have lying around and how much you bargain hunt) and is an easy afternoon project.

It's very simple to make: The most complex part is programing the vacation timers.

It's reliable: It always delivers the exact same amount of water, and there's no chance of flooding your house while on vacation.


  • 1 five gallon plastic bucket (or some other reservoir for water like a plastic garbage can.)
  • 1 smaller, plastic tub. (Like those disposable tubs for leftovers, or an old Cool-whip container, etc.)
  • 2 Vacation timers. ($12 each) Important:They must be able to be able to turn on for only one minute, which means you can't get the cheapest ones that go by the hour.
  • 2 small submersible pumps like the ones used in small fountains. ($7-$15 each) I used these (if still available) Theseare a good substitute. Or just Google "small fountain pump"
  • Several feet of vinyl tubing. ($1 a foot) (Make sure it fits the outlet of your pump. Mine was 1/4" inner diameter)
  • Several medium size binder clips. (Can substitute hot glue if you don't ever want to reuse any of the parts of this project.)
  • Ground fault interrupter (Recommended, though not required. But it's always a good idea when water and household current are this close together.) ($15-$30)


  • Craft knife.
  • Magic marker.
And if you're like me: first aid kit, fire extinguisher, poison control phone number,acid burn shower, etc.


About 30 minutes (or more if your vacation timers have weird cryptic instructions.)

Step 1: Overview

Cheap pumps and timers aren't particularly accurate. Running one pump for a precise time gave me drastically different amounts of water, and a to-the-second timer was a bit pricey and a pain to build. Setting up a flow meter attached to a switch was going to be tricky and expensive for such a low volume of water.*

So I made this two pump, two reservoir system that delivers exactly the same amount of water every time no mater how inaccurate the pumps and timers are.

The pumps are on two separate timers and run at two different times, one in the main reservoir pumps water into the top one. When it runs for too long and the excess water simply pours back into the bucket. When that one is complete the top pump pumps the container dry, which makes sure that you get exactly the same amount of water every time. No worry about over or under watering.

Lets get started!

  • Though now that I think about it, maybe a pressure switch and a balance might work.... hmm. Next time.

Step 2: Calibrate

First be sure that you have all of the parts and tools listed in the intro.

Next we need to figure out how much water you want to give your plant. To do that...

1) Put one of the pumps in the smaller tub.

Mine had suction cups to secure it.

2 )Put some water in the small tub then pump it out.

Hook up your hose to the outlet and run the pump until it stops pumping anything. This should leave a small amount of water at the bottom that the pump can't reach.

3a) Measure how much water you want your plant to get each time and pour it into the tub.

The volume of the tub now contains the water you measured, the water the pump can't pump, and the pump its self.

3b) Mark the high water level on the tub.

No project is complete without using a Sharpie.

4) Pour the water out and cut a 1" square with the bottom of the hole level with the high water mark.

Only the bottom edge of the hole needs to be precise. This hole is simply so all the extra water pumped in will flow back to the main reservoir.

Step 3: Prepate the Bottom Pump

This pump moves the water from the main reservoir to the measured one we suspend above it.

Place the pump in the bottom of the bucket.

(Or whatever you have. Big plastic water tight vessel. I found my pumps had a hard time pumping more than about 16" vertically, so make sure your pump can actually move water out of whatever you use.

Cut and attach a length of tubing.

This tube will carry the water to the plastic tub on top. It should reach from from the pump outlet to the top of the bucket, plus about 4 inches. You can always cut it long and trim it back. Attach this to the bottom pump.

Step 4: Set Up the Top Pump and Reservoir

Attach the top tub (and pump) to the top edge of the bucket.

I used a couple binder clips which is more than strong enough to support the weight and I know can survive getting a little damp, and have the added advantage of being able to guide the watering tube through the handles.

You could probably also use hot glue if you didn't mind some damage to your bucket and are careful not to melt the tub.

Aim the pipe from the bottom into the top reservoir.

Again the binder clip's handles come in handy for this. But again, hot glue would probably work.

Make sure the top end of the pipe is above the high-water level of the tub. If is in the water there's a small chance that it could start a siphon.

Tip: My pump came with a little right-angle adapter. If you're having trouble getting the water to go in the right direction, and you don't have an adapter you can hot glue the end of the tube shut and cut a hole in the bottom side of the tube.

'Run a length of hose from the top pump.

This one goes to your plant, so how long it needs to be depends on your arrangement

It's not a bad idea to secure the end to the bucket so it doesn't accidentally get pulled out of alignment. Again I used a binder clip.

Step 5: Test It.

Before we finish, let's test it to make sure it works.

Put some water in the bucket and run the bottom pump for a minute.

It should fill, and then overfill the top reservoir with the overflow recycling back into the main bucket. Make sure everything is positioned to minimize splashing, especially splashes that leave the bucket.

Run the top pump for a minute.

The pump should completely pump the water out of the top tub. It will probably run dry for a bit, but it's not much of a problem as long as the pump remains moist. Catch the water it pumps and measure it. It should be roughly equal to what you measured back in step #1.

Calibrate again, if needed.

If you got more water than you wanted then enlarge your hole in the tub. If you didn't get enough then some duct tape over the bottom edge of the hole will fix you up.

Step 6: Set the Timers.

Set up both of the vacation timers.

Follow the instructions that came with your timer. With mine I had to insert a backup battery and set the clock.

Tip: The battery backup on the timers is a good feature if there's a chance of blackouts or brownouts.

Plug each pump into a different vacation timer.

We use two timers because it's important that the pumps run at different times.

Set the timers to turn on on for exactly one minute each, but not at the same time.

For mine the bottom one comes on for one minute from 10:00-10:01 am every day. The top pump from 11:00-11:01 every day. It doesn't matter as long as they don't pump at the same time.

If you don't want it watering every day make sure you can get a timer that will let you set up a weekly schedule.

Step 7: Use!

Put the end of the tube in your pot, plug both of your timers into a handy outlet (or hopefully a GFI plug) and wait for it.

It's not a bad idea to be around the first couple times it goes off just to make 1000% sure that its working right.

Enjoy your vacation/plant negligence!

  • Be sure to refill the bucket every week/month/whatever. (I set up a reminder on my phone.)
  • Every once and a while take it apart and de-gunk it. It gets a little slimy after a few months.
  • I don't know if I'd use it with plant vitamins in the water, I suspect it foul up the pumps pretty fast, though I'd be happy to be proven wrong.

Improvements to make:
  • Some kind of cover to keep bugs and pets out. I don't have bugs or pets where I live.
  • Use a micro controller to control the pumps for more precision than vacation timers.
  • Hook it up to a water sensor in the pot so it only waters when it needs it.
  • Hook a float to a switch in the top reservoir so the bottom pump only runs as long as it needs to.
  • A flow regulator and splitter to water more than one plant at a time. (Just splitting the hose won't work well because the water will just go out the lowest hole.)