Introduction: Retrofit Any Planter With Hydroponic Watering System

About: Danielle Trofe Design is a Brooklyn-based design studio that promotes a function-forward, sustainable and socially responsible approach to furniture and lighting design.

Convert any existing planter into a hydroponic planter using a peristaltic pump and DC motor!

What you will need:

  • Planter pot with enough depth to store water at it's base (needs to be water tight, no drain holes)
  • Net cup
  • Hydroponic medium (in this example, expanded clay pellets)
  • Peristaltic pump
  • DC motor (6-12V)
  • Power adaptor, solar cells or battery pack to power DC motor
  • Electrical wire, soldering materials, or alligator clips
  • Clear tubing (off-the-shelf aquarium tubing)
  • Hydroponic Liquid Nutrients (optional)
  • pH balancing liquid and tester (optional)
  • Electrical tape & scissors
  • Power outlet timer (optional)
  • A plant!

Step 1: Material Recomendations

Below are a few handy links for materials and components needed for this project. I've also included links to 3D models for an option to 3D print a peristaltic pump to customize for your DC motor choice.

Hydroponic Supplies:

Electronic Supplies:

  • DC motor (6V-12V recommended)
  • DC motor speed controller (optional)
  • Power adaptor, solar cells or battery pack to power DC motor
  • Power outlet timer
    • Local hardware store

Step 2: Make Sure Your Electronics Are Compatable

Select your peristaltic pump and DC motor, I recommend 6-12V and if this is your first go around with these components and you don't foresee the desire for customization, then I strongly recommend purchasing a peristaltic pump that is paired with a DC motor (see material rec. page for link). I've experimented a bit with 3D printing the components of a peristaltic pump and customizing the parts to creating micro pumps. If you're feeling adventurous, take a look at a few pumps on Thingiverse and other 3D model websites for specs.

Note the volts/amps of your DC motor and choose your power supply and connections accordingly. Battery, converter, solar... all are compatible. In this example I use a 12V DC motor and motor speed controller that connects to a converter.

Step 3: Measure Planter Pot for Retrofitting Net Cup

Selecting the right size hydroponic net cup/pot to fit your planter is an important step! Here's a few considerations:
  • Select the pot you would like to retrofit with hydroponics
    • Large/tall enough to hold water at the bottom for your water reservoir
    • No drain holes, must be water tight
  • Measure the height and inner diameter of planter pot
    • At rim and 3-5" below rim
  • Select the right size net cup/pot for your planter
    • There are many different sizes of net cups with varying depths and diameters (see links on rec page)
    • Select the right measurements that will allow the net cup to fit snuggly in the planter while allowing 3+ inches of depth at the bottom to create a water reservoir
    • When sizing keep in mind that your tube will run up along side of the net cup within the planter, so add a 1/4" to your diameter measurement

In this example I use the following measurements:

  • Planter pot: 9H x 5.5Dia" (this is a bit tall, but good for demo)
  • Net cup: 4H x 5Dia" with 1.5" cut off from top
    • Modifying the net cup to fit your planter is a great solution for in between sizes

Step 4: Fill Planter Pot With Water, Balance PH, Add Liquid Nutrients

A Little Hydroponics 101:

  • Hydroponics is a soilless method of growing plants
  • Water is fed directly to the plants roots
  • The plants roots are supported my a growing medium (in this case, expanded clay pellets)
  • Liquid nutrients are added to the water to feed the plant

Create a liquid nutrient mix in a gallon of water. Read specific instructions for ratios of liquid nutrients, proportions vary by nutrient brand, plant species and growth cycle. I mix the solution in a gallon jug and keep it on hand to add water when needed to the plant/planter.

Fill planter (with nutrient mixed water) below level at which the netted pot/cup will rest within the planter. Test pH balance using test kit. Add acid or base droplets (a few drops go a long way!) until optimal pH of 5.5 - 6.5 is reached.

Step 5: Affix Peristaltic Pump and Connect Tubing

Attach peristaltic pump to top edge of planter. For this example I'm using a clear plastic planter to best display all the components and am simply taping (electrical tape) the pump to the top ridge. Secure tightly and upright. I encourage you to get creative, 3D print an enclosure or mount for the rim that will create a more appealing aesthetic for longterm use.

Cut aquarium tubing to measure from peristaltic pump tube to bottom of planter. Fit cut aquarium tubing snuggly within peristaltic pump tube. If the tubes are not the right size or don't create an air tight connection, consider using a different tube size or using tube connecting valves (aquarium supply store or Petsmart).

Cut second piece of aquarium tubing 2" in length. Attach to other peristaltic pump tube.

Step 6: Plant Plant in Hydroponic Medium and Fit Into Planter Pot

There are two options for planting:

  1. Grow a seedling and plant into medium once mature (1-2 weeks)
    • I recommend this Instructable for more details on growing hydroponic seedlings
  2. Take or buy a small house plant and carefully remove soil
    • First remove loose soil, careful to not damage roots
    • Soak roots and remaining soil in water, rinsing, and soaking until all soil is removed

Next take either seedling or soilless plant and

  • Fill the bottom of net cup/pot with a layer of expanded clay pellets (or preferred medium)
  • Insert seedling or plants roots of plant
  • Gently fill the remaining net cup/pot with medium
  • Make sure the plants stems and leaves are not covered my the soilless medium, but ensure all roots are concealed under medium

Place net cup in planter pod. The long reservoir tube stays underneath the net cup and runs up alongside it to connect with pump. The small 2" tube arcs over net cup and is directed at the center of the plant for water distribution.

Step 7: Connect DC Motor, Controller and Power Source

Connect DC motor to preselected power supply. Test the direction of the DC motor with connections, i.e. if the water does not begin to pump up into the tube and to the plant, reverse the +/- connection on the motor to reverse the direction of the motor.

I use a motor speed controller to increase/decrease the speed of the water drip. I also recommend using a power outlet timer to control how much water and energy you use. I run my system for 2 hours every 3-4 hours and less during the nighttime. The key is to not let the plant's roots dry out. You can customize your water distribution in coordination with the plants hydration needs and alter it for varying growing cycles.

Safety Warning: make sure the placement of your motor and electronics are away from water circulation and the reservoir

Step 8: Ta Da! Your New Hydroponic Planter!

Hooray! You did it!

Now watch your plant grow, monitor its hydration and nutrient needs. When you need to add water, pour directly into the plant, all the water will remain in your planter pot for circulation.

Suggested Add Ons:

  • Use moisture sensors in reservoir and net cup to measure and monitor water levels and plants hydration needs
  • Power your DC motor using solar
  • Create a lid with components nested/affixed to the underside to increase aesthetic appeal

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