Introduction: Small Indoor Hydroponic for $20

About: I was born in Friuli Venezia Giulia (Italy), when all grown up I graduated in Computer Engineering in Bologna. Shortly after the graduation, during a visit to Australia I decided to migrate permanently to Syd…

Would you like to grow food and cooking herbs yourself during any season, indoor?

Do you want to get to know the fascinating world of hydroponics for as little as $20?

This is one of the Instructables that can get you started!

I always liked to grow veggies and herbs since I was little, and during the past couple of years I have been trialling (and errors too!) many different types of hydroponic setups in my small apartment during my spare time.

The one that I am about to describe here is actually my favourite setup with the lowest maintenance, probably the lowest cost and the highest efficiency!

I came up with this design (I call it the "spider" hydroponic for its black long tubes irrigating the plastic cups) so that it would not be required to have an air stone and an air pump to oxygenate the water. The pump pushing water upwards inside the plastic container, creates enough aeration and irrigates the plants for them to grow nicely.

My design is not really like any of the conventional hydroponic type I know (eg: Ebb and flow/flood and drain, drip, NFT, DWC, etc). Probably the most similar is a drip system. The "spider hydroponic" is really effective both for the water oxygenation, and for the fact that watering plants from the top, seems to be more effective (at least based on my experience) especially if germinating plants from seeds.

Step 1: Materials Required

    • IKEA Samla black box 39x28x14cm 11l - about $3.00
    • IKEA Samla black lid for box 11/22l - about $1.50
    • Mini DC 12V 3M 240L/H Brushless Motor Submersible Water Pump (this model is my favourite water pump as it can push water with head up to 3M) - about $2.50 on eBay
    • Black irrigation pipe, two 90° elbows for the irrigation pipe, small irrigation flexible tube - about $3.00
    • 24h digital timer switch for the irrigation (with 1 minute intervals) - about $7.00 on eBay
    • 24h mechanical timer switch for the lighting (with 30 minutes intervals) - about $2.50 at IKEA
    • Old mobile phone charger for Nokia or similar (with voltage output less than 12V)
    • 2-way screw terminal strip to connect the pump to the mobile phone charger - about $0.70 on eBay
    • Sturdy used juice bottle
    • 6 plastic cups
    • Screwdriver
    • Scissors
    • Measuring tape
    • Cutter/sharp utility knife
    • Drill
    • Drill bits
    • Hole saw drill bit for the plastic cups
    • Some clay pebbles
    • Lamp and light (7 Watt fluorescent lightbulb in my case is enough)
    • Hydroponic organic liquid fertiliser
    • Some coconut coir peats (optional)

      Step 2: Construction

      • The first step is to complete 6 holes with the hole saw, on the box's lid, to make the plastic cups fit inside them.
      • We need two additional holes, one towards the middle of the box, to make the plastic pipe fit snug inside it, the second hole is on one of the sides for the pump low voltage electric wire (see pictures).
      • At this point the box is ready. We will have to prepare the 6 plastic cups. We need to cut them on the sides (according to the picture), so that the roots and the water can pass through the vertical cuts (careful not to hurt yourself if using a cutter!).
      • After the plastic cups, we should prepare the juice bottle. We need to cut the top off it, and also to make 6 holes to it (3 on each side), snug enough to make the small flexible plastic pipe just fit through it, to reach the 6 plastic cups. The 6 holes should be at the same height, so that the water will reach every cup at the same rate.
      • Prepare 6 plastic pipes of the correct size to connect the juice container to the plastic cups and fit them into the juice bottle's holes (see pictures).
      • Now we should test the juice container filled with water, to see if it works well and if the water reaches every plastic cup.

      Step 3: Construction - Cont

      • It is time to connect the water pump to the central irrigation pipe and fit the pipe through the hole. We can then determine the length of each of the irrigation pipe pieces, based on the height and length of the juice container.
      • Connect the two pieces of irrigation pipes together with the two 90° elbows.
      • Fit the pump's electrical wire to the box lid's hole on the side.
      • Make sure that the mobile phone charger is disconnected from the power and cut the final part of the cord.
      • Connect the pump to the mobile phone charger using a 2-way screw terminal strip.
      • Add some water inside the box.
      • Make sure there is no water around you and that your hands are dry, for safety.
      • Connect the mobile phone charger to see if the system works correctly (as shown in the video).
      • Fill half way the plastic cups with clay pebbles.
      • Fill the box with water, up to the bottom of the plastic cups.
      • Connect and set the timer for the lights. I run it 15 hours a day.
      • Connect and set the timer for the water pump. I run my water pump 5 times a day for 1 minute at the time.

      Step 4: Grow and Eat!

      The "spider hydroponic" system is now complete and you are ready to grow your favourite plants!

      Remember to refill the box with water every now and then, change the water regularly and put some nutrients in the water.

      What can you grow? I would suggest some fresh kitchen herbs, salads and small veggies. My favourites and most prolifics are: basil, bok choy and silver beet. In the picture you can see one of my harvests of bok choy.

      You can grow directly from seeds (as I did), or from small plants, making sure to remove all dirt from the roots.

      If you want to grow directly from seeds, based on my experience I would suggest to use coir coconut pellets (lying on top of the clay pebbles), to help seeds germinate as it retains more the moisture needed.

      Have fun growing and eating organic and fresh veggies all year around!

      Indoor Gardening Contest 2015

      Participated in the
      Indoor Gardening Contest 2015