Self Watering Recycled Plant Pot for Growing Herbs and Flowers




About: Just your average handyman.

Inspired by bbullet's Self-watering recycled vase instructable, this is the method that I have been using to make dozens of self-watering recycled planters. Thanks, bbullet!

The way that I am making these uses 2 or 3 liter soda bottles and it supplies the soil with just the right amount of moisture for the plants to grow. It's a little different than bbullet's way, but it's still made with recycled bottles and produces fantastic results all for the cost of a pinch of seeds!

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Step 1: Materials

You will need to gather these materials:

  • One 2 or 3 liter soda bottle with the cap
  • A piece of newspaper, a piece of plastic from a bag or a piece of aluminum foil
  • Cotton string
  • scissors or knife to cut the bottle
  • a drill (or something similar) for making holes in the cap
  • tape (optional)
*paper or some other decorative cover to keep the light out

Step 2: The Cap

To begin, I drilled holes in the cap for drainage and to accept the cotton string that will act as a wick to draw the water up into the soil.

I drilled one large hole in the center of the cap and eight smaller holes around it. The large hole is what will hold the string and the smaller holes will allow water to drain out.

Step 3: The Wick

I am using cotton string to act as a wick to draw water up into the soil. As the soil dries and the roots absorb moisture, the wick will bring water back up into the soil from the reservoir below and feed the plants.

I cut three equal lengths of string (about 15 inches long) and tied them together with a simple knot about 3 inches up from the bottom.

Into the cap, I fed the three short lengths of cotton string through the big hole in the middle of the bottle cap and pulled them through so the knot rests on the hole on the inside of the cap. The short ends will dangle in the water, and the long ends will go up into the soil to feed the roots.

Step 4: Cutting the Bottle

I used a marker to draw a line on the soda bottle to use as a guide when I cut it with scissors. The two parts that I was left with are the cup and the reservoir.

When the cup is inverted (with the neck down) and put inside the bottle, it should not touch the bottom. There should be about 2 inches of clearance so that the wick can dangle in the water but the cap cannot touch it.

Step 5: The Cup

The cup is what the soil goes into and where the plants grow.

Roots do better in darkness than in light, so they need to be blocked from sunlight.

To do this, I've tried three different materials. I have used a piece of black plastic from a garbage bag, aluminum foil and newspaper. I have found that newspaper seems to work best since it is biodegradable and helps to retain moisture. It is also easy to remove from the cup for transplanting. Best of all, it's the cheapest of the three since used newspaper can easily be obtained for no cost at all.

I put the light-blocking material all the way into the cup, trying to flatten it against the sides of the cup to increase the amount of soil that I can fit in later. Once it was in there nicely, I poked a hole in the bottom for the wick.

Step 6: The Cup Cont'd

I fed the cotton wick through the hole that I poked in the cup and screwed the cap on.

The cup is now ready for soil.

Step 7: Soil

Depending on each particular plant's moisture needs, I mixed up the appropriate soil with perlite, vermiculite or peat moss and was ready to add it to the cup.

I held the wick up into the middle of the cup and began putting the soil in. Having the wick run up in the middle of the soil helps it to absorb water more quickly and allows the roots to get to it much faster than if the three strands were separated and on the sides.

After adding a little bit of soil, I separated one string and made a coil in the dirt. I put a little more soil on and made a second coil. I put on a little more and made the third coil and then filled it up the rest of the way. I believe that the coils help to spread out the moisture better than just having them going all the way up the middle.

Step 8: Water

After all the soil was in the cup, I trimmed off the rest of the newspaper and thoroughly soaked the soil with water. Depending on the plants needs, you may not be able to use regular tap water, and since I have a rainwater collector that is what I use the most.

So, I soaked the soil thoroughly and let it drain for an hour. I also made sure that the bottom part of the wick was wet as well, since this will help it absorb better. Placing a dry wick into the reservoir will cause it to float and not absorb as well.

Take care to let the cup drain completely. Drips of dirty water into the clean reservoir water may cause algae to grow. The water should only need to go up, not back down into the clean water.

Step 9: The Reservoir

The reservoir is just the bottom of the bottle and is used to store water.

I put some water into it and placed the cup inside. There should be enough water for the wick to dangle into, but not so much that it touches the cap. I have found that too much water will encourage algae to grow since little pieces of dirt that fall through the hole in the newspaper contaminate the clean water. This isn't beneficial, because this design is meant to constantly feed the plant clean water and algae will make it harder for water to reach the soil.

Since the cup pressed down into the reservoir creates a vacuum, it makes the removal of the cup a little tough. To solve this, I drilled a tiny hole on the side of the reservoir to let air in. Now the cup can be removed easily for watering, transplanting or harvesting.

Step 10: Planting the Seeds

Now that the planter is finished, it is time to plant seeds. The planter is useful for growing small plants such as herbs and flowers or as a starter for larger plants that will have to be transplanted later. Make sure to provide the plants with the proper amount of sunlight that they need to grow.

The wick delivers clean water from the reservoir up into the soil and to the roots. This is quite useful, since the plants can be left unattended for periods of time because the soil waters itself. Basically, they can be left alone and grow with little care from the gardener. Using a two liter bottle, two inches of water keeps the soil moist for nearly two weeks or more. I have been pleasantly surprised with how well this works.

About once every few weeks, I remove the cup, water the soil, rinse off the wick and allow it to drain. This helps to wash out any buildup of minerals in the soil and completely rehydrates everything. Take care to let it drain completely so as not to contaminate the new fresh water in the reservoir.

Then, the cup goes back into the reservoir and I can walk away from it for another couple of weeks.

Step 11: Optional Step: Creating a Mini Greenhouse Lid

This step is optional, but the planter can be made into a mini greenhouse or terrarium with a second bottle. This is useful for plants that require a high humidity to grow.

I used another soda bottle and cut the bottom off. The place where I made my cut is right below where it begins to curve. Cutting it above this will prevent the new greenhouse lid from fitting in easily and snug. So, look at the bottle, observe where it begins to curve and cut a little below it.

The greenhouse lid will now fit into the cup easily and will trap the humidity. It will not be uncommon to see water beading up on the sides and dripping down into the soil. I have not had any problems with the water leaking back down through the soil and into the reservoir. I think that is because the wick will only absorb as much water as the soil needs to fill the deficit of water created by the absorption from the roots.

Step 12: Other Optional Steps

Now that my planters have been in service for awhile, I have noticed a few additional problems and have come up with some easy solutions.

First is the algae growth inside the reservoir. Since algae is a plant and plants need the sun to survive, the easiest way to prevent the algae from growing is to wrap the finished bottle with a piece of construction paper or something similar. This blocks the light from penetrating, plus it can be decorated.

And, after prolonged use of these bottles, I have noticed that sometimes the wick will wear out and fall off. It makes sense because cotton is made from plants and plants will decompose. This usually takes a while, however. What I've noticed is that by the time the wick rots off, there are already roots growing down where the cap is. This was easy, since I just removed the cap and let the roots grow down into the water. After all, who needs a wick when you have roots?

Step 13: Summary

These planters are simple to make and are made with recycled products that would normally be discarded. They can be decorated and given as gifts, made by children as projects or just left on a windowsill to grow fresh herbs or flowers.

The soil really does seem to stay moist longer than it does in a conventional flowerpot with regular watering. My favorite part is that the plants will grow with very little help or attention from me.

The fact that all the parts used (the bottle, the newspaper, the compost, rainwater) are all recycled or free and can be recycled again is what I like a lot. The planter can be used several times and can simply be tossed into a plastic recycling bin when finished.

I've made dozens of these and what I like the best is that I can grow miniature crops of herbs and flowers for literally the cost of the seeds and with little effort on my part.

Thanks again to bbullet and his instructable which originally inspired me on the basic design.

Have fun and happy gardening!

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    101 Discussions


    4 years ago

    Hey there, does the algae growing in the reservoir cause a problem for the plant? I'm considering growing both and stumbled upon this instructable. Would intentionally growing algae in the bottom be detrimental to the plant?

    I will be gathering these items for next years garden. I used rolled newspaper for some starter pots, and the plastic containers berries and lettuce are packaged in. built in drainage!


    4 years ago

    please i would like to know if it is suitable for planting Romain lettuce. is the 2 liter plastic bottle enough to grow such herb?


    4 years ago on Introduction

    Thanks! You did a good job. I just spent my afternoon doing it. It was really nice ;) I will post some pictures soon.


    4 years ago

    Thank you


    11 years ago on Step 5

    I don't the print would be a problem but the newspaper seems like it would work like a peat pot. Water a peat pot and within 24 hours the pot itself has soaked up all of the moisture, leaving the roots to dry out. To me, the black trash bag would be the best choice, as it does not soak up moisture and does not run the risk of letting light in.

    1 reply

    Reply 8 years ago on Step 5

    the trouble with a black trash bag is if the sun comes in the window it can overheat the soil and the plant roots. it's possible it could kill the roots, and the heated soil might dry out sooner as well.


    9 years ago on Introduction

    perhaps i did not read this article clearly but do we put water in the soil or in the reservoir so that the the soil will suck up the the water from the reservoir via the strings?  i am not so clear about this.  so when we plant the herbs do we fill the reservoir or water the soil?  sorry if the questions are idiotic.  thanks!

    1 reply

    Reply 9 years ago on Introduction

    You want to have water in the reservoir at all times. When you put soil in the cup, wet it also. As the water evaporates from the soil, it draws more water up the strings - kind of like priming a pump. Re-moisten the soil periodically.


    9 years ago on Introduction

    Great instructable! I really like recycling, but only as long as they serve a purpose. Would it affect it on any way if the whole container was permanently decorated?

    1 reply

    Reply 9 years ago on Introduction

    Nope. I once made construction paper sleeves to go over the outside of the pots. You might not be able to see your water levels, though.


    9 years ago on Introduction

    I first tried out with pebbles at the bottom.then graduated to two piece ones.Now I make two piece ones but with decoupage covering the whole bottle Cant pull out the top part to see how much water there is left. to overcome this problem I have left the flat part of the bottle clear and drilled a hole about two inches from the bottom for the excess water to flow out . The bottles are all placed in a basin of water for a while and once they are full ,they are taken out and left out for the excess water to drain out. I used fabric and jute and also paper napkins to decoupage the bottles. Also mat and bamboo screens.Plan to grow lettuce and herbs, but at the moment I have all sorts of plants.Just one had a problem- the roots found their way into the reservoir because I had drilled an extra hole in the lid for water to drain into the the bottom part .Couple of plants wilted a bit -the soil was dry.Dont know what happened.


    9 years ago on Introduction

    Recycling, yay!

     I just made four of these today after having some trouble with my oregano and thyme washing away when I try to water from the top and not staying moist enough in general.  

    I left the newspaper out, though.  

    1 reply

    9 years ago on Step 13

    You can view my sub-irrigated instructable here:

    Using the Google search feature with "sub-irrigated", my instructable was #3 . . . I think yours was #1! My thinking has evolved towards using a five gallon bucket for larger plants, but you could do the same thing on your smaller scale by removing the tapered neck of the clear bottle. Drill a small overflow hole at the desired maximum water height and fill with pea gravel to 1/2" above the overflow hole. This guarantees a crucial air gap between the potting mix and the water reservoir, so over-watering is impossible. Then a piece of Dupont's 15-year landscape fabric is used to keep roots from drowning in the reservoir. Then the bottle is filled with planting mix and is ready to plant. It's important to fully saturate the mix as you go -- any excess drains out the overflow. The bottle should be painted or shaded with a decorative cyclinder. I have ideas for auto-watering too so the water level remains constant. I hope to detail all this in my 2nd Instructable SOON but haven't put it together yet.


    9 years ago on Introduction

     Thank you so much for posting this instructable, now I have a new home for my Oregano and Rosemary plants :)


    9 years ago on Step 5

    Contrary to popular belief, plant roots do just fine in sunlight :) The reason that 99% of pots are opaque is because it helps nurseries control algal growth in their soil. I have over 20 plants in transparent pots, with various exposures to sunlight. All of them are thriving.




    9 years ago on Step 5

    This is really cool! It addresses the problem that recycling plastic isn't very profitable. This way your local recycling center doesn't loose money sorting it, and it still stays out the landfills. Bravo, sir! You've also solved a problem for me. I've been using the bottom parts to catch excess water but a plastic cup for the pot. This way one bottle will make a complete pot.