I built this little system because I like to make trees grow where they don't want to grow...in a pot!
I may find a seedling or take a cutting and start it in the hydro. Frequently, one will root and become viable, then can be re-potted.
Step 1: Container
The potting cups can be any style that fits into the container. The ones I chose are very brittle, and must be drilled with a soldering iron. The holes allow the solution to drain so that the roots can breathe between feedings.
The hard part is cutting the hole in the container lid. Consider the cup size and position, then decide on a hole diameter. Use a very sharp utility knife and work s.l.o.w.l.y. Don't cut your own you-know-what off. A hot knife would be easier and safer.
The bumper is made from 1/8in airline hose. Slit the length with a sharp knife. Once installed around the container lid hole, it will hold the cup snugly.
Step 2: Manifold
I had to throttle down the flow into the containers by reducing the tubing size. If not, one or more of the containers would overflow before the others could catch up. Blame that dude Daniel Bernoulli if it happens. Some creative fine tuning of the flow may be needed if it is a problem.
To make the feed hole use a step drill. A standard drill bit would dig and climb and tear and just make a mess. This 5/16in hole is so smooth that the tubing fits snugly and does not leak. No sealant required.
Step 3: The Workings
For this type of ebb and flow system, you must use an impeller pump. The pump will hold the proper solution level in the containers, then siphon back through the (idle) impeller after the power is cut. This one will push a 12 inch head with plenty of flow.
The timer came from...Goodwill. Two bucks. Most timers have presets that turn on for 30 minutes. This one I found has 15 minute increments. Set the timer to feed the plants three or four times a day. Start at sunup, and finish before sundown. Plants don't eat after the sun goes down, so you may be harming the roots by continuous feeding.
An aquarium air pump is desirable to keep the solution active and oxygenated. It runs 24/7. Any air stone will work fine.
Step 4: Reservoir
Arrange the air stone, pump, and feed lines.
Plastic wrap is a must to keep the air bubbles from going all over the place.
This is a closed system. What I mean is that the reservoir will completely empty into the containers, then siphon back. On the first run add water to the reservoir as the containers fill to bring the level up. As the solution evaporates, water must be added to maintain that level.
Step 5: Happy Plants
I pot the plants with 50-50 vermiculite and potting soil. Black Magic is my first choice.
I use standard clay pots. It is much easier to control the soil moisture content.
Beyond that, it's all about growing things.