John,

What flow rate and spacing of the T-tape; IE, GPM per foot at 18" spacing or GPH per foot @ a2 foot spacing? If you don't have this, let me know the brand and number of tape? What is the spacing of your pots? Aloha

Emitter spacing is 8" for 15 Mil t-tape that flows 40 GPH per 100 feet @8 psi.

I expect to have about 6 psi pressure and possibly 2 rows off the header with plants spaced about every 12 to 16 inches for about 20-30 feet rows.

Thanks for the help, I have heard about container vegetables burning up in hot weather and I wanted to use the auto timed irrigation to help them be productive as well as survive. I will probably set up some kind of heat shield for the container (boards wrapped with foil) to divert heat from the pots.

John

John,

With 8 " spacing you will have some water falling between the pots. Also each emitter is giving about 0.27 gph. This equates running your system about 2 hours to get your 1/2 gal every three days or 3/4 of an hour every day. Is this set up from a rain barrel or low water tank or a pressure reduced water supply? Aloha

Pressure reduced water supply - It will be 8 feet above the water supply, so I'll probably rig a separate water supply from my ground level drip tape.

I guess I should try something like 30 min/day for 75 degree weather, 45 min/day for 85F, 1 hour/day for 95f?

What do you think? The roof is fairly reflective. I suppose if there is water dripping under the pots, that is a sign of excess watering.

Thanks,

John

John,

Your description is somewhat confusing. You will be performing trial and error anyway but try to calculate to get a system that gives you what you need at the highest demand. You can always reduce time or flow for less demand needs. My suggestion is a 1/2" pvc pipe with 1/16" hole drilled in it to the spacing you need. Measure the depth (inches)of the water out of the holes with a cup for a specified length of time. You want to time to the system to get 1" of water a week. If needed, drill the holes slightly larger if needed to decrease the irrigation time. Trial and error until you have a system that works for you and the plants are thriving throughout their growth cycle. This system works well with low pressure. If you have normal pressure then reduce your pressure to 25 psi using a pressure regulator but then use 25 psi drip tape with the right spacing for your pots and a known flow rate per orifice or 100 feet length. JMHO aloha

OK, thanks, I think we are speaking different languages here. T-Tape, made by John Deere is an agricultural drip tape that runs at 8 psi. I've got a bunch that I'm playing with this spring.

http://www.deere.com/en_US/water/productsequipment/products_ttape.html

John

I would like to make the point that with 12 inch pots, I can fit 2 drip openings per pot with 16 inch spacing between pots and no wasted water drip points with my setup.

John