Need help from the fluid dynamicists out there

Not a brewing project, but I'm drawing on some of my equipment building experience for this one, and could use some of the expertise I know is on this site.

I am in a rental with a carport for a backyard and a very small front yard. I want to do a small garden in containers in my front yard. Couple tomato plants, couple peppers, tomatillos, an eggplant. I bought two tallish -- 2-3 ft planters for the tomatoes and a "mexican strawberry pot" (with the multiple openings coming out of the side for the peppers and the rest). Bought most of the plants with my mom today and was talking about this plan. She's a knowledgable gardener and said that one of the big problems with this kind of setup is that the pots will dry out quickly and so it's hard to keep them watered. She said -- specifically regarding the strawberry pot -- that she has seen setups where people ran a perforated pipe up through the bottom and used this to facilitate watering.

I am working on setting this up for all three planters and bought a bunch of PVC and fittings. I am headed down a route to where a single hookup to a hose would water all three pots at the same time (through a 1-in 3-out cross connection). I am also envisioning an arrangement where the tall tomato pots are side by side and the strawberry top sits on top and between them (kind of resting on the lips). This will minimize the footprint (not a lot of space to work with) while maximizing sun exposure.

I know enough to recognize that if I don't do this properly, all of the water will go to the lower pots and none will make it to the "upper level". I also know that if it were only the two lower pots, I would want to make sure that the holes in the pipe were similar in number and height so that the flow to each would be similar. It seems to me that by putting fewer holes in the lower pipes and more in the upper, I should be able to ensure that water goes to each. Is there an easy "back of the napkin" calculation I can do to figure out how many holes I want on the top pipe relative to the bottom ones? I'm not looking to ensure absolutely equal flow or anything -- my watering regimen will be as simple as turning the hose on for 5-10 minutes per day. But I want to make sure that everything gets water.

Or is this much too complicated and I should just set it up so that I can water each "level" separately?

Ever hear of a sprinkler?

if there's enough pressure, you will get equal watering to all the pots. so either crank up the pressure and hope it's enough, or drill smaller holes

Sir Humpsalot said:

Ever hear of a sprinkler?

Click to expand...

Touche. Well played, sir.

Yes, I am over-complicating this a bit, I suppose.

your overcomplicating this...but simply by restricting flow to the lowers the water will still make it to the top...now if the holes on the bottom are 1/2 the size of the ones on the top this doesnt mean that they will get 1/2 the water. They are under more pressure and probably get just as much water as the one with the larger holes on the top. If this helps, the average home gets about 40-80 psi water pressure. So use that to help with the dynamics of it. You want to get technical? hows this. A 2" line gets 200gpm at 25psi. Also, 2" loses apx. 10psi per 10' of vertical incline and 10psi loss over 50ft horizontal lay. That should help you work it all out. after that its basic math.

Math? I love math. I do math -- ok, basic math -- for a living. But sir humpsalot comments did get me thinking in another direction . . . not sprinklers exactly (there's not much else in the yard that needs the water and i'm somewhat conservation minded). BUT I'm now considering a setup that would have only one distribution line to the top pot. A hole at the top of this pot would water those plants (burble burble) and at the bottom would be two lateral outlets that would run to the two lower planters, ideally through some sort of sluice type affair. Part of my reasoning here is that the allowable complexity increases if the creation can be classified as a "water feature" :cross:

Thanks for the input, guys. I will throw up some pics when I'm done.

Now to figure out a way to turn the carport in the back into a hopyard!