May 12, 2023

Aeroponic Grow Tower

This is a Aeroponic Tower that I am trying to make.  I’ll start by saying… I have no real reason to try this other than the fact that the idea of Aeroponics/Hydroponics is very interesting.  Besides some limited gardening in the past I don’t have any experience growing stuff and I don’t have any delusions that I’m going to grow all of my own food this is just something I wanted to try because I like to make stuff.  After doing some very limited research I found a few videos on YouTube showing DIY vertical grow towers and I am going to be using Chris Loh’s Videos as a starting point to make one.  I do have my doubts that I’ll be able to grow anything as a lot of the videos showing this stuff really don’t have any follow up showing whether they work well or not but either way it should be fun project to try anyway.

This is my crude drawing for the double tower design I want to try.  It will probably use metal frame to keep if off the grass which gives me an excuse to use my welder that I don’t get to play with enough. I should be able to make this out of one single piece of 10′ pipe (to keep the cost down) and a bunch of fittings.  Although I’m not sure if the water reservoir will be big enough.

To begin I measured and marked a line 4 feet from the end of the non flanged edge of a 4″ piece of 10 foot Scheduled 10 PVC pipe.  I used a piece of paper wrapped around the pipe as a straight edge and drew a line around the pipe.

Using a hacksaw I cut off the 4 foot section of pipe.

Next I deburred the ends with a deburred tool.

I then cleaned up the inner edge with some 80 grit sand paper.

Using a pencil on a box I drew a center line along the length of the pipe.

Starting from one end up to 3 feet I drew a line every 4 inches along the pipe.

I made up my own template using Chris’s measurements and then cut out little windows at the end of all of the patterns.

The template is then laid on the center line on the pipe with the first window on one cross mark and the side windows are used to mark lines on the pipe.

I do mark number ones and twos along the center marks to make sure I put the template in the right place. The T-marks show me which way the slot lines will go.

I then use a flexible ruler to mark the slot lines.

Here is what the staggered slot lines look like when fully marked up.

Next using the hacksaw again I start to cut the slots making sure to stop short of the end lines.

I then use just a blade to square up the cut to the line to finish up the slot.

Next a 45° cut is made on a piece of 2″ schedule 40  PVC pipe.

For the next step I moved outside and using a heat gun I heated up the area around the slots. (use wore a respirator for this step for safety.)

Once the slot starts to droop from the heat a bit I insert the 2″ PVC with the 45° to form the pocket for the Net Cups.  (see Chris’s video for a better explanation.)

This is how the first tube came out. I did tear a few of the edges but this was my first time doing something like this.  Overall it came out pretty well.

Next I cut out a bunch of 5/8″ rings from the 2″ Pipe using a chop saw (to save time) I stuck a piece of wood to the saw with some double sided taped to act as a stop.

Using the heat gun again I heat up the openings and put the rings in place.  Once the tube cools down the rings should stay in place… if not I’ll add glue later.

Here is how they fits so far.

Next it was time to test fit the Net Pots.

Everything is looking good so far. Now I just need to repeat everything for the second tube.

Now that I have both tubes done and everything worked out I have to go buy all of the other pipe fittings for the base.

A quick trip to the store and I have the rest of the piece for the tower. This is the general layout of all the parts but I’ll get in to the specifics as I go.

I only have about 24″ of 4 inch pipe left to join all of these parts.

The next thing I did was cut off a short 2.5 inch section of the remaining 4″ pipe.  This section gets inserted into the top of the 45° Y intersection piece (which will be the filler port) and will hold the top cap in place. (this does not get glued on.)

I then cut the flanged section off the rest of the pipe.

That flanged section was then cut down the side…

.. and I then stuck that inside the T fitting and marked were the two edges overlap at the bottom.

That mark is how much I have to cut of this section so it fits in the pipe with the edges still butting up to each other.

Using a straight edge and a razor knife I trim of the excess.

A quick test fit and it looks good.  With this being what might be a underwater seem I probably should have used this piece for the cap which will not need to be sealed.  I’ll just have to see if it leaks I guess.

I will be using PVC cement to glue all of these pieces together

Here they are after gluing.

I trimmed off the rest of the flanged end which was the only waste of the entire 10′ section of pipe. The remaining piece was cut in half leaving two 8 3/4″ sections.

These pieces were then aligned and marked to the 4″ 90° elbows.

Here is the base of the tower after gluing all of the parts together.

Next the tower pieces were also glued in place.

I guess its a good idea to put grates in the top of the tower to help disperse the water and let it drip onto the cups so I found these floor PVC drains to try.

The only problem is I want to put them in the tower pipes upside down to leave room for the water output spray nozzles. (that is if I use nozzles)

So what I did was turn down the lip on my mini lathe.

They sort of fit but won’t sit low enough at this point…

… so I heated up the pipe until I could press them in flush. This work out well because they do not have to be glued in place if they don’t work out.

This also allowed the top caps to fit over the tower pipes.

This is the pump I’m going to try.  It’s a 12v 185GPH submersible pump that is suppose to have a 21ft lift capability (which seems crazy).  I went with a 12v pump because I envisioned using this with my Solar Tracker project maybe.

I found a 1/2″ PVC fitting that screwed right onto the pump which was nice and easy.

The first thing I did was test the lift capacity of the pump and it feed water up straight up the entire length of 10′ 1/2″ pipe so that was pretty impressive.

The next thing I did was to  bore a hole in each of the three caps to accept the 1/2″ PVC pipe.

The motor and pipe (which was trimmed to 53 inches) are dropped into the base and the cap is slid down over the top to hold in everything in place.

I forgot to take pictures of the making the top T assembly but it’s just a T-Fitting, two 12″ long 1/2″ pipes, two 90° elbows, and then two more 3.5″ long pipes feeding back down through the caps.

I thought about using a 1/2″ cap on the inside of the cap and then drilling a bunch of holes to make a nozzle that sprays the water more evenly over the grates.

… or even just placing the cap on the grill to act as a diverter to spray the water around.  I need to test the actual water flow first to see if any of that is even necessary.

I will be using this rubber cap to cover the fill port.

I removed the hose clamp and cut a small slit in the cap to feed the power cable for the pump through.

With the exception of a little clean up the basic tower is complete at this point and ready to test… I’m just waiting on the proper power supply for the pump before I can test the flow.

While I was waiting on the power supply I figured it would be a good time to start the seeds.  I didn’t like how tight the holes and slots were in the cups so I modified them to allow the roots more room to grow through.

I don’t have a starter tray so I just used a cardboard box for now.  It’s hard to see but I marked the cups with paint in different colors to show whats planted in them.

These are the Pure Coconut Coir Netted Seed Starting Pellets I will be using.

They fit perfect in the bottom of the 2″ cups.

I then soaked them in water to get hem to expand.

Next I opened up the mesh a bit at the top and made a small hole with a wooden skewer.

These are the five different seeds that I will be trying in this tower.  I doubt they will all be successful as they all have different PH and PPM requirements but I’ll be happy if at least one of them gets to harvest. I know for sure the tomato’s from seeds are a crap shoot.

I always wonder what lettuce seeds look like as I’ve never actually seen a flower head before.

5/14/23 – 28 cups sowed and ready to grow.  (in hindsight I probably should have done more than the exact amount needed encase some didn’t germinate.)

I couldn’t find a starter grow tray locally so I just used a aluminum tray/cover from the grocery store. The cups were transferred to this and placed on top of my refrigerator as the heat is suppose to help with growth. Now its just a waiting game to see if anything germinates… This should give me enough time to make the stand for the base.

Three days later the lettuce is starting to sprout.

After initial testing I decided try try the caps as diverters first… I drill and tapped a 8-32 hole in the cap…

That allowed me to secure the cap to the grate with a  single stainless steel screw and washer.

This seemed to work good to distribute the flow better and it looks like it should get to every cup.   I did run into a problem though where the water would sometimes only feed to one side after the T-fitting in the feed pipe.  I may try to use nozzles which will hopefully cause a little bit of back pressure so both side should feed.  I just need to get two more caps to test this theory out.

This is the nozzle design that I am going to try next. I designed it to only spray toward the front of the tower because…

… as you can see here with the grate removed all of the cups are only aligned toward the front of the tower so water is not really necessary in the rear. More testing is needed at this point.

This is what I am envisioning for the stand for the tower.  I keep it relatively simple so the tower can just drop into it from the top.  While the square PVC type base that Chris showed in his video seems pretty simple all of those fittings add up and I’m not sure how you would go about cleaning everything out once algae started growing in it…

… plus the thin walled 3/4″ square tubing that this will be made from is free and readily available to me.  This is all dependent on whether I can cut and weld the round parts and make everything square.

5/20/23 – Unfortunately I left the seedlings on the refrigerator to long and didn’t expose them to light so they grew leggy so instead of trying to save them I’m just going to restart them over and try better this time.

This is the scrap metal I will be making the stand from. It’s just about 1″ and .75″ square tubing.

Here I measured and cut all of the piece I will need.

My welding skills are horrible especially with this thin wall tubing… but I managed to weld all of the piece for the Top Brace together (I ended up going with a square design to save time) and then welded on the Legs to that.

Next I welded bottom braces together.

Then it was just matter of welding the Bottom Brace assembly to the Legs.  Nothing about this is straight or square but it should still work well enough.

After a quick paint job to keep it from rusting to quick I test fit the tower into the stand. So far everything looks like it should work.

It’s super sturdy and shouldn’t have any problem supporting the weight of the plants… (If they grow that is). The new nozzles worked great too and I am getting good flow to both sides now.

This is the Plug Timer I will be using to power the pump.  It’s suppose to have 15 minute incremental setting but it’s not very acurate and is closer to 9-10 minutes on 17-20 off… but what do you want for under $10.

I will be using this AeroGarden Liquid Nutrients to feed the plants.  From what I read you don’t need to worry about PPM with this stuff but well see how well it works out in the long run.  I will be using 4ml for every Gallon and my system holds about 3 gallons.  I have read some bad reviews for this stuff where it can get moldy in the bottle and is hard to pour. (especially in such small quantities)

What I did to try to alleviate those problems is to machine up a fitting which attaches through the cap…

… and has a small pick up weight on the bottom…

… and using a small syringe I can get the proper ratio to add to my tower.  (12ml in my case)

I won’t have to open the bottom ever again so hopefully this will keep it from going moldy (if it really does) and will allow me to easily extract what I need from the bottom of the bottle.

5/29/23 – I don’t know if the new plants are “started” enough but I went ahead and put them in the tower and started the pump running.  (The tomato pants on the bottom are from the original start.)

Now we sit back and see what happens….

6/11/23 – 2 week growth update.  Everything but the spinach (not shown) is doing well.

6/19/23 – Week 3 = Had a minor setback… something decided to snack on my lower level tomato plants.  Which is not surprising seeing as there is a family of 6 Groundhogs living under my shed, plus a raccoon, a rabbit, and a opossum running around the yard  at any giving time.  A few survived so I had to take some other measures…

I fenced in the Tower with some chicken wire to try to close off the snack bar… we’ll have to see if it helps. Overall the plants look like they are doing well though.

6-/26/23 – 4 week Growth Update = There is only one good spinach plant but two more sprouting (which I replanted), The lettuce is getting crazy, the Kale is doing really well too, and the Pepper and whats left of the Tomato plants are getting pretty big too.

7/5/23 –  Another weekly growth update.  Had a storm roll through with crazy rain so there were a few more casualties.

The size of these kale leafs are crazy.

7/18/23 – Between the animals, bugs, and the crazy rain storms I’ve been getting the tower has been taking a beating.  I’m not sure how the lettuce is going to hold out but the Kale is still getting huge and one tomato plant is still going strong.

7/24/23 – With continued crazy weather… things were starting to take a turn and some of the lettuce was starting to yellow and a bunch of stems where broken on the other plants. I don’t know how but something is still munching on the lower tier stuff too. Bugs have also completey ate the lone spinach plant.  (I hate spinach anyway)

I’m also not sure what this thing is that was growing at the very top but it’s definitely not something I planted.

7/26/23 – Things were not looking good overall so at this point I just decided to harvest what I could.

I was able to harvest a good bunch of the Lettuce and a few Kale leafs.

After a good cleaning I at least can enjoy a salad after all of that work.  This was more about the journey than the destination (so to speak).

The roots on the Tomato plant were super long. I think at this point they where more Hydroponic than Aeroponic because they were definitely in the water at the bottom.

This is the end of the tower…. for this year anyway.  I still need to clean it out but all of the roots are intermingled together so it might be easier to remove the cups after they dry out?

---

Overall I’d consider this a success for my first time with Aeroponics even though I basically only got a salad out of it.  After all this was more of a learning experience then trying to get actual food out of it.  I probably didn’t feed everything correctly (I basically tried to keep everything around 800-1000 PPM) and I never really checked the pH levels so maybe things would have gone better if I did or if the plants types weren’t all different.  If I do this again I’d probably change the tower design too as the plants did seem to crowd each other when they grew larger. I’m not sure the lower plants got enough sun.  Maybe if the weather wasn’t crazy and the animals didn’t snack on the lower tier stuff it would have gone better but I’m glad I gave this a try and I honestly think these towers could work quite well if done correctly.  Maybe next year I’ll try a horizontal Hydroponic setup and keep it away from the critters.

The End.

---

All Information, Pictures, and Material is copyright © 2023 by Stephen Thone and may not be used for any personal or commercial purposes without the consent of the author. All rights reserved. The Author makes no guarantees or warranties as to the accuracy or completeness of, or results to be obtained from accessing and using the Information herein.