Hydroponics Tuesday

Outdoor Aeroponics, Generation #1
4/15/2008 7:41:12 AM

First and foremost, we have some unfinished business to attend to this week...

We need to announce the winner of the Fix My Stuff, Win A Prize contest. This contest was inspired by the Do-It-Yourself aeroponics plans that I published a few months back.  I wanted to encourage participation by the group to improve the plans for all of us.  The contest's winner is Red Icculus.  Red made several very practical suggestions for subtle improvements to the desigh:

  • Red recommended that the sprayers be replaced with 180° units, rather than the 360° sprayers that I used in the original.
  • Red also recommended that the system be sealed with weatherstripping.  After some experimentation, I settled on 1/4" wide self-adhesive rubber weatherstripping.  It works wonderfully.

As the proud winner of the contest, Red will receive a random assortment of Hydroponics Tuesday swag.

 

Ok.  On to the regularly scheduled blog post.

Firstly, we start with a retraction this week... Last week, I mentioned that we would be receiving some new LED-based lights to test.  After speaking with the manufacturer, they expressed that they need more time for research, development, and refinement.  We will probably get to test them at some point, but for the moment, we are delayed. 

The arrival of the Fort Laramie strawberries has caused me to get my act together regarding outdoor aeroponics.  I've been thinking and planning for a long time, but this last weekend, I made the all-important transition to actually making it happen.

Fair Warning:  This is entirely experimental. I haven't published plans yet, and for good reason.  This is completely untested and unproven.  Here's what we've put together, and the basics of how it all works:

We purchased PVC fence post material from our local Lowes.  Fair warning:  Home Depot doesn't carry the right stuff.  We used the larger size PVC, rather than the smaller stuff (that fits overtop a 4x4).  This stuff is commonly called the 6" PVC, even though the measurement isn't really more than about 5 1/2".  Before I bore you with more details, here's the first photo:

Hydro-2008-04-14a.jpg

We drilled the PVC section several times for all the plant sites.  Important tip... When you're making your own "small plant" aeroponic units, you should use the Botanicare net pots, not the General Hydroponics ones.  There is a huge difference.  For more details, look here.  We used a drill press, but you could do it with a regular drill just as well.  When using the Botanicare pots, a 2 3/4" hole saw does a really nice job.  Take my word for it on this one... Buy the right tool.  Don't try to muddle your way through without one.  It's totally worth it, as the pots form a very tight seal in the holes.

The photo below gives a better view of the feed and return system.

Hydro-2008-04-14b.jpg

The first site in the system is used for the feed.  I took a 1/2" "bulkhead" fitting, mounted it inside a Botanicare "filler" plug, and made a really nice modular hookup.  Although I cannot find a good photo of one at the moment, Botanicare makes wonderful plastic "plugs" that fit the 2 3/4" holes perfectly.  The bulkhead fitting is mounted into the plug, and you have a watertight 1/2" passthrough.  I bought the bulkhead fitting through Grainger, but you can easily get them at a decent aquarium shop.  The bulkhead fitting pictured isn't exact, but it's close enough.

Here's why the larger PVC is important... It's just large enough to mount a plastic sink drain (purchased at Home Depot) as your water return.  All that white PVC that you see is just standard plumbing, bought at the local Home Depot.  It leads back to the reservoir.

A closer look at the hookup:

Hydro-2008-04-14c.jpg

The black vinyl tubing that you see on the left is the pressurized feed line.  The white PVC fitting is just an elbow with a hose-barb on it.  The feed line is connected to a long piece of 1/2" hard PVC pipe which runs underneath all the pots in the large tube.  Sprayers are positioned every 7" (the holes are drilled 7" on-center), so that a sprayer is directly between each pair of pots.  This design makes disassembly fairly easy (as the plug / bulkhead can be popped up and unscrewed).  The feed is positioned directly above the drain, so that all our "water" is run to one end of the unit.

The reservoir is mostly buried in the ground.  We buried it in an attempt to stabilize the water temperature, and hopefully to get some free cooling in the coming summer months.  To save space, the whole unit is supported by ladder-brackets on the side of our smaller shed.  This keeps it off the ground, and at a convenient height for berry-eating.  Although the entire unit looks level, it's actually offset by about 1/2" from end-to-end.  This causes the water to fall towards the return drain naturally.

The whole system is powered by an ActiveAqua PU550 pump.  As I've stated many times before, I love ActiveAqua pumps.  They are strong, reliable, and inexpensive.  At full retail price, this pump is $32.  The pump is immersed in the reservoir.  I use a 1/2" ID hose for the feed.  It's more than enough.

In theory, this should be our last cold week of the year.  If this holds true, I'll migrate the strawberries into the new outdoor aeroponic unit sometime next weekend.  I hope it works, as this design would be pretty easy to duplicate.  Although I haven't done a writeup yet, I estimate the cost to build this unit at about $100.  If I remember correctly, I spend about $25 on the big PVC, $30 for the pump, $10 for the reservoir, and about $30 on plumbing.

That's it for this week's DIY installment.  I'll post updates as I make new discoveries.

If you haven't been watching the CO2Boost Study, it's an interesting read.  The CO2 supplemented plant is really starting to get a lead on the control plant. 

Last item of business for this week, a quick photo of our rapidly-expanding Black Beauty Eggplant (in it's own private aeroponic unit):

Hydro-2008-04-14d.jpg

Posted By Red Icculus, Tuesday, April 15, 2008 7:58:29 PM
Why thank you, sir. It is a pleasure to win your contest, but the real credit goes to my soon-to-be fiance, Amanda.

I see you have 14 sites. The Fort Laramie strawberries ship in 25 plants. Are you going to double up in each site?

Also, the burying of the reservoir is ingenious. It is a trick I first heard about with aquaponics to keep fish alive between extreme heat and hard freezes.

Also, I wish more people knew about your tips about the net cups. The Gen Hydro ones are ok, but Botanicare are where it's at. Thanks for the writeup.
Posted By Ben (Hydroponics Tuesday), Tuesday, April 15, 2008 8:10:45 PM
I was waiting for you to find it... Make sure to contact me privately, and we'll see about getting your swag in the mail to you.

Indeed, the new aero has 14 sites, but one is used by the feed. It's only got 13 available for plants. I'll be filling it out with the Fort Laramies. Some will stay inside (I'll probably make a DIY aero with five small sites), and some will go to friends. Out of the 25, 23 are still alive. All said, it wasn't a bad batch.

Do you think I should convert the net cups post into a full article?
Posted By Red Icculus, Thursday, April 17, 2008 7:55:48 AM
I think you have a potential article about the net cups right there. It is great info and I don't think I have ever come across a comparison. It is usually something people don't usually consider, so go for it!
Posted By Motheragent, Sunday, April 20, 2008 7:08:00 PM
I like the way you think! It's fun to see your designs and projects.

I really like the use of the vinyl fence post. I have vinyl fencing around my yard and balcony. This design will integrate very nicely into my homes existing architecture without looking too ultra hi-tec. I'm excited to build one of these.

The above website is one that I enjoy reading. It is a fun site with free recipes using organic fruits and veggies. With all the produce you'll be growing, you may appreciate a few new ways to serve them up.
Posted By Ben (Hydroponics Tuesday), Sunday, April 20, 2008 9:58:03 PM
That's a pretty good site you recommended. Here's my favorite item:

http://www.rawfoodporn.com/wp-content/uploads/2008/04/funny-pictures-rabbit-opens-mouth-for-carrot1.jpg

The PVC fence material has worked out pretty well. I transplanted the new strawberries into it today, and I'll be adding the nutrient mix in the next few days. Let me know if you need any help building yours. The most important part is the 2 3/4" hole-saw.