DIY Hydroponics on the cheap

You don’t need to spend thousands of dollars to grow salad, tomatoes, or strawberries hydroponically. Here’s how to do it for less than $150, everything included.

A tiny tomato plant is starting its journey.

A bit of theory

Tools you’ll need

  • An electric drill or screwdriver is helpful.
  • Drill bits + a 2” hole saw ($9) is helpful (although you can use a knife to cut holes in things if you want to save money)
  • A sharp knife. An X-Acto blade ($9) works great.
  • Some caulk ($7)

Shopping list

The core system

  • Solar water pump ($20) There are a lot of options for the water pump; any aquarium pump should do. I like using one that’s solar-powered because it means I don’t need access to a power socket. It also means that the system runs during the daytime and stops at night. That makes sense to me! You can buy any submersible water pump. Don’t go crazy — the first 4(!) pumps I bought were way too powerful. A little goes a long way here. A cheap $14 pump probably does the trick.
  • Five-gallon bucket with lid (This will set you back around $6 from any hardware store, or $10 from Amazon). The 5-gal bucket will become your water expansion tank.
  • 12x one-gallon buckets with lids ($33). This is where your plants will be bathing and enjoying the sunshine. You can also use 3- or 5-gallon buckets for larger plants, but I like the convenience of having multiple, smaller growing vessels. Make sure you get lids, because you’ll need ’em. (Alternatively, if you want to grow large plants — tomatoes or marijuana, for example — use 5-gallon buckets for that, too; you can buy special lids for them ($8.50 each) that already have a grow basket in them.)
  • 50x two-inch plastic grow baskets ($9) This is where your plants will sit.
  • Silicon tubing ($10). The tubing is there to lead the water around your system.
  • Pack of 6 hose barb fittings ($14). You don’t strictly need this — there are cheaper ways of attaching silicon tubing to buckets. However, using proper barbed fittings makes life so much easier; I probably wouldn’t make do without it. You’ll need two per bucket, so a kit of six is enough for three buckets.
  • Hydroponic plant food ($26). This stuff lasts quite a while, but if you want real bang for your buck, get the 1-gallon bottles instead ($84)
  • 1.5-inch rockwool grow plugs ($10 for 28). This is the medium where you’ll be growing your seeds
  • Leafy green seeds ($18 for 4,000). This is where the magic begins!

Upgrades

  • Air pump ($9) and Air diffusion stones ($7) to oxygenate the water. Because the water is moving around, you probably don’t need to oxygenate. Having said that, plants are much happier if the water has a bunch of oxygen, so this would be my first upgrade once you’ve got the basics down.
  • Hydroponic pH control kit ($20) I bought one of these, but after a while, I realized that the pH in the water stayed pretty much in range without much help from me. I also refresh all the water every month or so anyway, so perhaps it isn’t worth it. On the other hand, if your plants grow slowly or seem unhappy, give it a whirl.
  • In-line filters ($8 for 10) I don’t know if these are strictly necessary, but I noticed that sticking filters in the water lines helps control algae, and keeps the water cleaner, which should mean that the water pump keeps working for longer. Again, if you change the water frequently, you probably don’t need these.
  • Grow lights ($40) My current hydroponic system is outdoors, so I let the sun do the shiny part of the plant growing. I’ve had it indoors in the past, and it works great, but take this from me: If you want to move it indoors, test everything thoroughly (flooding outdoors is annoying, flooding indoors is expensive and annoying), and slap some lights and a timer on there.
  • Solar power: If you want to go green, let the sun do the power delivery, too. A solar panel ($100)+ battery ($80) + charger controller ($15)+ inverter ($43) — This is all stuff I had laying around from a trip to Burning Man and now keep handy in case there’s a power cut. I probably wouldn’t buy any of this stuff, especially for a hydroponic setup, but if you want to have some fun with it all… Go for it! (A less DIY version that includes the controllers and inverters etc, in a user-friendly package would be to use a Jackery ($300) and a solar panel ($170), but again — that makes things real expensive real fast.)

Putting it all together

Building the system

Holy Lid!
Barb fittings: Installed
The little ‘straw’ on the right helps the water level go up and down throughout the day
Tubes, wires, and hoses, oh my.
Juuuuust getting started. Go, little plant, go!
  1. Use a toothpick to poke 4 little holes in the rockwool.
  2. Place a seed on top of the hole, and push the seed in, about half an inch (1.5 cm).
  3. Place the rockwool on a plate, and pour a little bit of water on top of it.
  4. Keep an eye on it — add a little bit of water daily. You don’t want it water-logged, but you don’t want it drying out either. Ideally, the plate stays (mostly) dry, and the water saturates the rock wool.
  5. Keep at room temperature. Supposedly 80F/25C is perfect, but seeds find away, in my experience.
  6. Depending on the seeds, you should see sprouts in 5–7 days.
  7. When the roots start poking out of the bottom of the rock wool, you’re ready to move your little baby plants to the hydroponic!
About a week after sowing, some of the varieties are starting to poke out of the rock wool. Others are only just starting to sprout. It varies from plant to plant!
See the white-ish tops on the rockwool? That means it has dried out too far. Give ’em some water — they should look like the second picture. Here, you can also see that one plant has broken free of the rockwool, and that at least 2, maybe 3 others are starting to take shape.
Day 1 outdoors

Troubleshooting

Overflowing

Siphon control clamps / flow control clamps are your friend.
To reduce the flow, move the hose to the narrow part. To increase it, move it the other way. You know what they say — if it’s stupid but it works, it isn’t stupid.

The water doesn’t flow properly through the system

Growing the system

--

--

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store