Mini Hydroponic Grow Pot




I wanted to construct a simple and really cheap hydroponic grow system. wanted to use as many recycled items as possible. Well sort of..
After much thought, I hit upon an idea that that would allow me to grow one plant, and an extra bell pepper starter I had would do the trick.

Step 1: Drilling the Holes

First thing I did, was to drill a hole in the top of two empty 100 count CD containers. One hole in the sides near the open end of each was to allow the nutrient delivery tube to be run through. The CD cover that would be on top also had a slightly larger hole drilled through. This hole would be used to install a bell siphon. One more hole in the bottom was made to allow fluids to drip back into the reservoir in case the pump turned off before the water drained back through the bell siphon.

Step 2: Constructing the Mini Bell Siphon

I need to construct a mini bell siphon. A permanent marker, and a few pens that were absconded from my junk drawer. I also grabbed some black tubing, but later I decided I Might just use a plastic drinking straw. The pens were gutted and sized out so I could get a feel for what would fit.. And how. I found it amazing how a permanent marker that you think has been dead and dry for a couple of years will suddenly be very capable of ruining your day. :). A place near the tip of the marker body was then drilled with 4, 1/4" holes to create the bell siphon housing. Looks like it will work well. The black plastic tube was a little too large so I had to go with the straw. And that fit better as a siphon in the newly created bell housing.

Step 3: Installing the Bell Siphon

The tip of the newly completed bell was then pressed through the bottom hole from the inside of the upper cd cover, ( now the grow bed ) the body of another pen was twisted over the tip on the outside to tighten the whole thing together like a bulkhead fitting. The pen body on the outside was too long, so it was shortened. A plastic straw was pushed up through the inside until it touched the top of the bell, then pulled out about 1/4" from the top and trimmed to match the outside pen body. This created a great siphon.

Step 4: Installing the Pump

I had an extra 12volt pump from an earlier project. The water pump, a 12v model I imported from China will work very well with an old 6v cell phone charger I had. The Pumping capacity was supposed to be rated at about 240 liters/hour.. It is not, more like 24/hour, however, that is Actually what I wanted anyway. The tube and wiring was routed through the holes drilled earlier in the bottom cd case/reservoir.

Step 5: Slip Fitting the Two Cases Together

I slip fitted the two cases together. The bottom of the one CD case fit perfectly in the top of the reservoir. No cracks, no leaks, looking good.

Step 6: Make the Grow Media.

This is an easy and interesting step. I had purchased a couple of nylon soap scrubbies from a local Walmart for a buck. These were to become the growing media. I believed that plant roots would like this. It was very porous, allowed water and air to flow freely to the roots.
I decided the best way to use them was to cut the string inside them allowing them to completely unravel. Primary reason is that I didn't want the string to start rotting, besides it would have fallen apart anyway. I wadded them back up and stuffed them inside the upper growbed. Two of the scrubbies fit well.

Step 7: Creating the Plant Support Base

The base of one of the CD cases will become the lid and plant support.
The spindle was a large twist out, nice. However it was not big enough. So I traced out a circle using a 2" net pot.
I cut out just inside the traced area slightly smaller so the net pot would fit tightly in the new hole.
All that being done, I inserted one of my pepper plants I already had in a net pot. This Plant has grown in a hydroponic setting since sprouting so I see no problems right now.

Step 8: The Net Pot and Plant

Seems the plant liked its new home. The first photo is the original plant with no real rooting. Nothing much to see really. No roots, not much to see at all. I didn't think the plant was very happy.
The second photo is the same pot, same plant, two - three days later. Something has greatly stimulated root growth. These look like they tripled their growth rate.
In the third photo, 3 days after the second one, I could not pick the plant up without damaging roots. Seems the plant is just loving this grow media and roots are rapidly growing through the mesh.

Step 9: Nutrient Delivery

Seen in the last picture on step 8 is the nutrient delivery tube. I felt the liquids were flowing through too rapidly. This was causing the media to flood too quickly and never drain properly. The ebb and flow is needed to let the unit "breath" and exchange air with the roots and oxygenate the nutrients. So what I did was cut the end of a wall anchor off and insert the plastic anchor into the tube. I also inserted an inch long piece of plastic micro tubing to direct water flow at the net pot better. Then when the pump was on it resembled a mini shower. The result was the water flow was greatly slowed, allowing the plant to absorb nutrients better.
The pump is controlled by a timer that is set to run 3 times daily for thirty minutes.

Step 10: Finished, for Now

And finally I have a pic of the completed unit placed near the window of my "home office of horrors". the early morning and most of the evening is spent under artificial lights, approximately 16 hours of light per day.
The last photo is from this morning. ( 5 days after starting the project ) Seems the plant is enjoying its new space. The roots have grown deeply into the mesh.

Well end of December and I couldn't resist peeking. And roots are loving the scrubbies mesh. Large tap roots have made it to the bottom of the container and the smaller feeder roots are threading their way into view.

Step 11: Update: What Has Happened Since I Started This.

First photo is the plant as it looks today. The Roots (second pic) are still a little more brownish than I like but are away better than the gooey mess I found.
Well, week(ish) ago I accidentally stressed the plant a little too much. What had happened was I introduced too much nutrients to the mix which resulted in the yellowing of nearly all the leaves, I mean .r.e.a.l.l.y. Yellow. Everything drooped, stopped growing, and dropped the only few flowers it had.
Recognizing what I did, I immediately flushed the system and refilled with just plain ole tap water and let it run for a couple or three days. I then flushed the system again. And reloaded with a waaay weaker solution, modified. The plants crowns responded with a neat, near immediate greening up. Needless to say I was happy.
The modified nutrient solution consisted of a 1/8 strength mix of miracle grow tomato mix, a B1/iron solution, and light addition of Epsom salts. This was mixed in a gallon of aged/filtered water from my aquaponic system. What happened after that is absolutely fantastic. All the leaves started to green back up and the poor plant has gone into heavy bloom! The last couple of pictures are a very small showing of the blossoms opening up. And there are dozens of buds trying to get hold as well. I can't wait for this plant to give me a few peppers.

Hydroponics and Indoor Gardening Contest

Finalist in the
Hydroponics and Indoor Gardening Contest



    • Classroom Science Contest

      Classroom Science Contest
    • Planter Challenge

      Planter Challenge
    • Barbecue Challenge

      Barbecue Challenge

    12 Discussions

    JJ Slabbert

    25 days ago

    Tnx for the share. I like the mini bell siphon. I designed a 3d printed bell siphon for an IoT rain gauge. It works 99% of the time, but some times the bell siphon leaks. By leaking I mean one drop enter the siphon, and then one drop is siphoned out, where all is supposed to be siphoned. Any advice may help. My project is at

    Such a simple but effective setup. Many of the systems on my site support much larger yields, but also at a higher expense.


    4 years ago

    Very cool
    But i wish you could have gone into more detail/photos of your bell siphon. Very cool none the less


    5 years ago

    Currently I use a general purpose "miracle grow" with a product called "B1", "superthrive" will do as will, and one called "liquid gypsum" which contains calcium. Since my water is super hard and alkaline, I also have to add a fair amount of "PH Down" to correct the ph values.
    There are much better products I would recommend tho "MasterBlend" is a highly recommended product I hear of quite often. In the future I will be using that one.

    Nice Instructructable! I do have a question. I am just beginning to explore hydroponics and was wondering what "nutrients" you are using in your water. Thank you.


    5 years ago on Introduction

    Excellent idea and use of available materials - at this rate i will have to live on my kitchen windowsill as the plants take over.
    Thank you.


    5 years ago

    The color on those leaves is fortunately not because of heat. Those were plants recovering from too much nutrients in the water. That grow bed is using the Kratky method. Sometimes bell peppers don't do very well with that. That and those plants are more than 3 months old. But finally they are growing very well.


    5 years ago

    I've notice your plants are yellowing on the tips. I'm not certain but it could be caused by the tin foil over heating since tin foil absorbs heat. Try a cheap alternative mylar. You could get a safety blanket at any camping store. It also been prove to reflect 3x more light!


    5 years ago

    That size of case is what was on hand. Besides the 100 side will give just enough room for one plant


    5 years ago

    That's quite a large cd case. Did you go with the 100 cd case because that's what you had on hand, or in an effort to keep the roots out of the siphon? nicely done btw.