Aeroponic System Spray Hole and Pipe Length

by Walberto Ralon
(Mt. Prospect, IL, USA)

For the design listed on your site, using the 4"-6" PVC pipes, about how big of a PVC section are we talking about? Typically at the hardware stores around me, PVC pipes are sold in 10' sections. What total length pipe did you spec out the 60 PSI pump for? Is there a formula to use in case I wanted to scale beyond something just for home use? Also, you stated that its just better to drill holes instead of attaching spray nozzles. Would the coverage of drilled hole apply the nutrients to the root system sufficiently? Your site is awesome and I appreciate the advice! Thanks, Walberto Ralon

Answer: Walberto, for the convenience of our other visitors, I believe the hydroponic system you are referring to is the innovative aeroponics design here. This aeroponic system was designed around 8 foot lengths of 4" PVC. I don't think there would be any problem with using 10 foot lengths of PVC, but at some point there is not going to be enough pressure in the 1/2 inch line to make the spray hole at the end of the pipe work properly.

This problem is much better described in this section here on when to use a manifold. The problem of maintaining the proper pressure in the lines by limiting the volume in any one section of the aeroponic system not only applies to the construction of a slightly longer (10 foot) system, but ultimately is the key to scaling up the hydroponic system for something more than home use. The use of a manifold solves a fundamental problem of fluid mechanics, and once you understand the basic idea it will be easy for you to use a pump with a much higher volume to distribute pressurized nutrient solution effectively to a much larger system.

Whether you are talking about a manifold in a four pipe system or the manifold in a 200 pipe system is really irrelevant. For my four pipe system, you need a 1 1/2 inch line of pressurized fluid. It is capable of feeding four 1/2 inch lines up to 8 feet (and possibly 10 feet) long. This manifold configuration works well, given the fluid volumes involved. Just as the larger 1 1/2 inch line feeds the smaller 1/2 inch lines, so too must a larger-volume line be feeding each 1 1/2 inch line, should you decide to scale the operation up. Each line has a limit to how many smaller lines it can feed and still be effective.

If you were going to construct 4 of my aeroponic systems, for example, you might require a 3 inch (or possibly even a 4 inch) pressurized line to feed the four 1 1/2 inch lines that go to each of the four systems....which in turn would be feeding four 1/2 inch lines in each system. And, if you decide to power up 6 of the homemade systems instead of just four, you may want a 6 inch pressurized line feeding two 3 inch lines, which in turn would each feed 3 - 1 1/2 inch pressurized lines (one for each system).

As far as the spray holes go, as long as they are made properly (small and clean) and you maintain the proper psi in the aeroponic system, the nutrient solution forced through the tiny holes fans out quite nicely. In addition to this fanning, the water tends to splatter quite a bit as it slams into the insides of the PVC pipe in between the planting sites. The end result is very thorough coverage in the root zone.

One thing you want to make sure of is that your long pipes are properly supported underneath every two feet. Otherwise, long lengths of PVC pipe tend to sag over time. I hope this sheds a little light on this very technical subject Walberto, and Happy Growing!