Here's one I did some years ago. It is no longer in service, but I may revive it one day.
A Large Scale Wick Irrigation Experiment
Here's something I played with for a hoop house (before it blew away.) Watering is a potential issue, especially in a Texas summer when containers often dry out between even twice-a-day waterings.
After "turning it on," by day four, all thirteen young plants went through a 104-degree cloudless day with no sign of suffering and no supplemental watering. On the afternoon of day four, I checked them and was dismayed to see that there were signs of moisture, areas of darker soil on the surfaces. Dismayed, because I thought my wife must have watered them and had spoiled the experiment for the day, even though she had told me they were doing fine. I checked them with an uncalibrated soil moisture meter and found that at root depth, the meter showed "5" on a scale of 1 to 10, just where it should be for nearly all plants that don't require especially dry or wet soil. But I found she had not watered them at all. They were being maintained in good condition on the wick system. Every third day the sewer pipe reservoir is visually down enough to take more water, but it clearly could go a long weekend without filling. Obviously, this will not be the case with 80 or even 40 containers on a row and probably not even with a dozen fully mature plants.
The calculated volume of 40 feet of 4-inch pipe is about 26 gallons (208 pints). Estimates of how much water a mature tomato plant needs vary wildly, probably due to differences in climate container size, fruiting or not fruiting, and soil. A mature tomato plant under 30% shade on an otherwise clear, sunny day is said to require anything from two pints to a gallon of water a day. But clearly, if the system is supporting 40 mature tomato plants in fruit, at least two refills per day will be required. I suspect it would always be a matter of keeping an eye on it and adjusting any automatic filling mechanism according to how quickly the water level drops.
Note that in one photo the pots are properly raised so that no part of the internal wick is below water level. Otherwise, it will siphon downward and run out of the pot.
