How to Build an Indoor Hydroponic Vegetable Garden - Dengarden - Home and Garden
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How to Build an Indoor Hydroponic Vegetable Garden

With a master's in sustainable development, Susette helps Southern California water agencies carry out their water conservation projects.

Although there are many different forms an indoor hydroponic system can take, they all operate essentially the same way and have the same potential benefits and problems. The form you end up with will depend on how much and what kind of room you have, the kind of lighting available, the supplies and tools you have, how much you want to spend, and how patient you are with DIY projects. Because the basic hydroponic operation is the same, once you understand it, you can create any adaptations you want to that improve upon the basic design.

Chard and lettuce grown hydroponically. Note how big and healthy they are.

Chard and lettuce grown hydroponically. Note how big and healthy they are.

The Benefits to Growing a Vegetable Garden Hydroponically

Here are some of the benefits of using a hydroponic system to grow plants:

  • Food plants are healthier and taste better.
  • Flowers and herbs have a more vibrant color and scent.
  • All plants grow faster and bigger, e.g. the same variety of tomato plant grown in soil is only 1/3 the size of one grown hydroponically, even when the seeds come from the same packet.
  • If grown indoors and kept clean, there are few issues with pests and disease.

There can be problems too, but most of those are with improper setup. I've included a section near the end that describes some of them.

Radishes grown hydroponically, fed by nutrient-rich water flowing through bare roots.

Radishes grown hydroponically, fed by nutrient-rich water flowing through bare roots.

Building an Indoor Hydroponic Gardening System

Whether you build a system yourself or buy a kit, in general, these are the parts you will need along with plants and maintenance supplies:

  • A reservoir for the liquid (water/nutrient) medium
  • An aquarium-type water pump and hose for circulation
  • An aquarium aerator stone
  • LED grow-lights for the dark side of the window
  • Some kind of structure for holding pots
  • Opaque containers for plant roots (needs to be dark inside to prevent algae growth)

I looked through a number of systems on YouTube to find one that would be of average ease to build and still work for the inside of a house or apartment—one that was vertical to take up the least amount of space but still have lots of plants. The following video shows the windowfarm I liked best. There are lots of steps, but it's doable, and the supplies are easy to find and cheap enough to buy. Most people with carpentry tools can handle this project.

I've listed detailed directions after the video, so you can print them out to follow after you've seen how it all works. Although the video shows a vertical garden built to go outside, if you add grow lights, you can use it inside as well.

Hydroponic Indoor Garden Setup

If you watched the video, you will have noticed that this system uses PVC piping, a plastic fence post, and a bucket to build the windowfarm.

  • The PVC piping is cut into holders for the plants.
  • The fence post holds the plant holders vertical, while water drips down the inside (protected from insects) to water the roots.
  • The bucket holds and stabilizes the fence post, and is also where you aerate and fertilize the water.

The table below shows the materials and tools you'll need to build this system. The instructions start from the bottom up: How to prepare the bucket first, then the post with pot holders, then the water distribution tray on top.

Hydroponic System Equipment and Supplies

Start by gathering all your construction materials and tools together. Look to see what you have first, then what you can borrow, then buy the rest. The plant supplies can wait till later, if you like.

MaterialsEquipment/ToolsPlant Supplies

4 ft. of 3" PVC pipe

Compound or hack saw

20-22 plants of your choice

6 ft. of 5" vinyl fence post (hollow)

Jig saw

25 each 3" net pots

Flat 5" vinyl cap (for post) & 5" decorative cap

Saw angle block (jig)

Liquid fertilizer*

5 gallon bucket with lid

2 mini-clamps

Water pH test kit

1/2" slip to thread fitting

Caulking gun

Plant grow light

1/2" female thread to bar fitting

Drill & bits

Mellow music for growth

5" inspection port (like for boats)

Pencil & measuring tape

Submersible water pump

Electric fan (optional)

Silicone caulk

6 ft. of 3/8" plastic tubing

3/8" grommet

PVC vinyl fence cement (glue)

Instructions: Prepare the Water Bucket and Lid

  1. Draw a 5.25" square on the bucket lid. Drill 1/4" holes inside the corners of the square. Starting at one hole, cut the square out with a jigsaw. The post will fit in here.
  2. Next to it, cut a 5" round hole. Glue the inspection port bottom into the hole. Screw in the cap.
  3. Cut a 1/2" notch in the rim of the bucket for a pump cord.
  4. Beneath the bucket carry hold, drill a 1/2" hole and insert a grommet (for airstone).
  5. Insert the post into the bucket to see where the lid goes on the post. Take it out again with the lid attached to the post. This will help you position the holes for plant holders.
Inspection port bottom fits into round hole cut in bucket lid. Port lid screws in and keeps it airtight.

Inspection port bottom fits into round hole cut in bucket lid. Port lid screws in and keeps it airtight.

Cut Out the Plant Holders

These are the holders that your net pots will fit into. You'll need the 3" drain pipe, the saw jig, and a clamp.

  1. Cut the 3" sewer drain pipe into several 4" pieces.
  2. Insert one 4" piece into the saw jig. Place a clamp in front to hold it still.
  3. Saw through the pipe at jig angle to make two slanted standoffs (holders).
  4. Repeat with all 4" pipe pieces. You should end up with about 24 standoffs.

Prepare Post for Plant Holders

  1. Saw off 4" of post end. This will be used for the top later.
  2. About 4" away from new end of fence post (opposite bucket lid), start drawing positions for each standoff. There will be six on each side. Divide/mark a post side into equal sections about 9" each. Do the same on the opposite side.
  3. On one of the unmarked sides, start about 8" away from the top end and mark five or six sections. Do the same on its opposite side. This staggers positions on each side.
  4. Place the oval edge of a standoff in one of the sections with long edge down. Draw around the edge.
  5. Remove the standoff and move it down to the next section. Draw another outline and so on, until you have filled each section.
  6. Turn the post over and do the same thing with all three other sides.
  7. Now you're going to cut them out. Drill four 1/4" holes inside the edge of each outline. Use the holes to cut out each oval with the jigsaw.
  8. On the bottom of the post, beyond the bucket lid, cut a large notch out of one of the sides (about 6"x3.5") to accommodate the water pump inside the bucket.

Install the Plant Holders

  1. Using PVC vinyl fence cement (or epoxy), glue standoffs into the oval holes on one side of the fence post. Imagine the post standing. The round edge of each standoff should be facing up. Let the glue dry - approx. 10 minutes.
  2. Turn the post to another side and repeat, letting the standoffs dry before turning to the next side. Finish the other two sides the same way. Let them all dry.
  3. Using the caulking gun, caulk around the outside of each standoff where it meets the post (to make it waterproof). Repeat on the other three sides.
  4. Turn the fan on and let all of it "cure" for a few hours (or overnight).

Prepare the Water Sprinkler Cap

The sprinkler cap will be a two piece structure that includes a bottom tray and a decorative cap. Only part of this next procedure is shown in the video. First gather the 4" post piece you cut off, the "flat" vinyl cap (it's actually a slight pyramid shape), both fittings you bought, the water hose, your drill, and a pencil.

  1. Place the flat cap on your workspace so the pyramid part is on top (as though it were sitting on the post). Center the post piece on the cap and draw around the edges to mark its position. Set it aside.
  2. At the pyramid tip, drill a 1/2" hole.
  3. Now drill about 15 each of 1/4" holes, spaced evenly across the cap, inside of the square you marked.
  4. Find your post piece and glue it in place on its square. Let it dry. Caulk the outside edges to make it waterproof. You now have a tray.
  5. Through the center hole, screw your 1/2" slip-to-thread fitting on the top side of the tray into the 1/2" female thread-to-bar fitting on the bottom side of the tray.
  6. Push one end of your water hose into the fitting on the bottom. The fitting should automatically grip the hose. If it doesn't you might have to glue it in.

This is where the water goes - pumped up through the hose and the fittings, spilling over the top into the tray, and dripping down through the holes.

The flat cap actually has a little pyramid top. Drill the center 1/2" hole on the point and the smaller holes around it.

The flat cap actually has a little pyramid top. Drill the center 1/2" hole on the point and the smaller holes around it.

Slip to Thread Fitting

Assemble Your New Indoor Vegetable Garden

Now let's assemble the whole thing. In addition to what you've put together so far, here is what you will need for this step: Water pump, decorative cap, and water. You might need a rubber mat and small ladder or stepstool also.

  1. Position the bucket inside the house near a window. To protect the rug or floor, place a rubber lined mat underneath.
  2. Place the pump in the bucket with the electrical wire fitting into the notch on the bucket rim.
  3. If you use one, place the aerator stone in the bucket. Pass the hose through the grommet and attach it to your electrical supply.
  4. Stand the post up close to the bucket. Place the tray on top, with the hose running down through the post.
  5. Fill the bucket 3/4 of the way with water.
  6. Lift up the post and insert into the bucket. Attach the water hose to the pump. Clamp down the lid, but open the port, so you can see what's going in the bucket. The post should stand up straight.
  7. Plug the pump into your electrical outlet (or power strip). Turn the pump on and check the water flow to make sure it's going up through the hose and coming out of the fitting on top.
  8. Plug in the aerator, if you're using one.
  9. Check to make sure everything is working right. Check the top tray and every standoff to make sure nothing is leaking.
  10. Then put the decorative cap on top and you're ready for plants.
Anticipate the wonderful crops produced with hydroponics, but don't go overboard. There's still a learning curve.

Anticipate the wonderful crops produced with hydroponics, but don't go overboard. There's still a learning curve.

Insert Plants Into the Hydroponic Tower

For plants you can choose ferns, herbs, vegetables, fruits (like strawberries or tomatoes), or marijuana in some states. This step is the most fun. You will need plants, net holders, fertilizer, and grow lights.

  1. Pull plants out of their grow pots. Wash the roots bare.
  2. Immediately insert plants in a net holder. Place the holder in one of the post standoffs.
  3. Keep going until as many standoffs are full as you want.
  4. Add liquid fertilizer to the water in the bucket, according to manufacturer's instructions.
  5. Turn on the pump and let the water flow.
  6. Mount your grow lights so they shine most strongly on the front side of the post away from the window.
The red glow on this windowfarm comes from LED lights balancing light from the window on the other side.

The red glow on this windowfarm comes from LED lights balancing light from the window on the other side.

It is the marriage of the soul with Nature that makes the intellect fruitful, that gives birth to imagination.

— Henry David Thoreau

Potential Problems With Hydroponics

Most of the problems incurred with hydroponic systems can be prevented by the way the system is set up. Here are some:

  • Clogged pipe: Keep the bucket covered where water collects. Make sure your pump has a filter and keep the filter clean. Also arrange the water channel so there are no sharp bends that could kink.
  • Insects: Keep the plants fertilized so they stay healthy. Insects are attracted to weak and sick plants. Keep the upper tray covered too, so there's no place to breed.
  • Weak light: Nearly all plants, especially herbs, need plenty of light. Windows don't provide enough, so be sure to supplement with plant grow lights.
  • Plants drying out: Make sure water is getting to all your containers. You may have to poke another hole or two in the top tray on whichever side isn't getting enough.

Most likely your system will not be perfect the first time you set it up, but if you have chosen this system to use, and have followed directions as carefully as possible, the resulting problems should be minimal. Resolving them will give you greater skills and more insight into what your plants need. Let the issues that arise and the plants, themselves, trigger your imagination to bigger and better ideas.

More Reading

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: How often do you change the water and add new nutrients?

Answer: Of course, you know I'm going to say, "That depends." (lol) It depends on the size of your reservoir, whether it's covered or not, how close it is to heat and/or light, and what kinds of plants you're growing, as to how often to replace the water. When it gets low, you'll need to refill it, but not necessarily replace it.

Take note of how much water your reservoir holds. When you add water, measure it and keep a log. As soon as you've added 1/2 of the tank size, then it's time to replace the water. In order to avoid shocking your plants, you'll only replace 1/2 of it with fresh, clean water. (Don't replace the whole thing.) Add nutrients.

If you need to clean the tank, take your plants out and pour out all the water, but keep 1/2 of it in a container. Now use a non-soap sponge to clean the inside of the reservoir. If it's really dirty, you can use baking soda to scrub with. Rinse it out, then pour back the water you kept, and top it off with fresh water until the reservoir is full. Add nutrients, then the plants.

Question: What would be a good selection of fruits and veggies and any suggestions as to where to find good grow lights?

Answer: Most of what people grow with a hydroponic system are veggies and herbs—veggies like lettuces, cherry tomatoes, radishes, kale, cucumbers, spinach, even green beans. For herbs, you can grow cilantro, parsley, chives, dill, basil, mint, any of the smaller sized herbs. Strawberries are the easiest fruit to grow. The other fruits are vines, trees, or big bushes that need to be outdoors.

For grow lights, this article will show you the best ones. Amazon.com is always a good source, although you may have shipping delays right now, because of the flood of orders they're currently filling.

Comments

Susette Horspool (author) from Pasadena CA on July 25, 2015:

Build away adevwriting! Come back here afterward and tell us how it went. And thanks for reading, commenting and (I hope) sharing.

Arun Dev from United Countries of the World on July 24, 2015:

Thanks for sharing information about an Indoor Hydroponic Vegetable Garden. It would be cool to build such a garden. Voted up!

Patsy Bell Hobson from zone 6a, SEMO on January 30, 2015:

I learned so much reading this hub.Great writing. ^+

Johnique Davis from Illinois on November 16, 2014:

Thanks and will do

Susette Horspool (author) from Pasadena CA on November 16, 2014:

That's great Johnique. Good luck with it. Let us know how it goes.

Johnique Davis from Illinois on November 16, 2014:

Thanks for sharing. Recently, I moved to an apartment after living in a house for years. I thought my days of gardening was over. I will certainly try my hand at this innovative way of gardening.

Susette Horspool (author) from Pasadena CA on August 26, 2014:

Tomatoes from the store are pretty insipid, aren't they?

Nick Deal from Earth on August 26, 2014:

As long as this results in tomatoes tasting better, I'm on board

Scott A McCray on August 25, 2014:

I love it when creativity starts to flow!

Susette Horspool (author) from Pasadena CA on August 25, 2014:

Thanks for reading, sharing, and commenting everyone. Now you guys have got ME thinking again (lol). I originally had a suggestion to grow earthworms in vermiculite in the top tray for their castings, but I don't think that would work for this system, because of the tray's slight pyramid shape.

For aquaponics, you'd have to have something to hold the tower/s up inside the tank. Oh, the lid again, but with four or five cutouts to accommodate towers. This system would need less lighting, if you go vertical instead of horizontal and place it in front of a window. The tank could be an aquarium, with a plastic landscape across the back to block sunlight and add beauty, with food towers growing up from it. The whole thing could be a gorgeous living room live décor. Wow!

Scott A McCray on August 25, 2014:

Now it's got me thinking...maybe integrate this with small scale aquaponics...fish make fertilizer, plants and bacteria consume waste. Fish and veggies for dinner. While aquaponics generally uses a media filled bed, I'm thinking the tower could work well, too. Hmmmm.

poetvix from Gone from Texas but still in the south. Surrounded by God's country. on August 25, 2014:

Kudos! Awesome job on the instructions here. Loving the subject too, very useful. Two thumbs up.

Mary Hyatt from Florida on August 25, 2014:

You did a great job with info, etc. on this Hub! I just installed a hydroponic Aqua Farm system for my Betta fish. I am able to grow wheat grass for my cat, and it keeps the water nice and clean.

Voted up, etc. and shared.

Judy Specht from California on August 24, 2014:

Well done. I especially liked your recommendation of organic fertilizer. It really is much better than chemical.

Susette Horspool (author) from Pasadena CA on August 24, 2014:

Unfortunately I don't have photos, but the guy who made the video has a whole bunch of others on his website (though not of this one). He's been working with horizontal hydroponics for awhile already and has a hydroponic greenhouse. You both might be interested, Scott and Brie. Here is his website: https://www.youtube.com/user/HydroponicsIsCool/vid...

Scott A McCray on August 24, 2014:

Outstanding article - do you have any photos of it in use? I plan to try this some day soon - it would be neat to do a time lapse photo gallery from planting to harvest. Thank you!

Brie Hoffman from Manhattan on August 24, 2014:

LOL, well I'm interested in hydroponic systems so I bookmarked it for when I can actually get one. You sure went into a lot of detail..pretty amazing really.

Susette Horspool (author) from Pasadena CA on August 24, 2014:

Thanks Brie. That was a quick response you gave!

Brie Hoffman from Manhattan on August 23, 2014:

Wow, what an in-depth well written article!