opt,

Let's make an assumption to start. You have 12" spacing so that you have one emitter per plant. Each emitter is 1/2 gph. You need 1/2 gallon put on your plants every week. That would be 1/4 gallons 2 irrigation cycles a week. 1/4 gallon takes 30 minutes each cycle with the 1/2 gph emitter and 15 minutes with 1 gallon. If you go with 6" spacing you have two emitters per plant or half the times stated previously the same hold true for using a 2 gph emitter at 12" spacing. The closer the spacing or the bigger the emitter increasing the flow rate for your particular system pressure. You need to have knowledge of your system flow rate and pressure to make your decision unless you want to do it by trial and error. JMHO Aloha

Well, I kind of lucked out. I found a very good price on adjustable bubble emitters ($0.25 each). They adjust from 0 GPH - 10 GPH. So I took all the guesswork out of it and will play around with different flow rates until I figure it out....trial and error as you stated!

I'll report back bc I saw that this question has been asked, but never answered several times.

My emitters will be installed 12" apart and are in clay soil that is annually being amended.

If you can get adjustable emitters, I'd say go for it (got mine from irrigationdirect.com). This will allow you to have different flow rates for different veggies (like celery or squash that need more water than potatoes).

So, I'll update this post as I learn how long I have to water at the different flow rates to get adequate coverage...will include other conditions like soil, air temp, veggies, etc...as I go.

opt,

I guess trial and error it is. keep us informed of your experiment. Mahalo Aloha

@optimistique did you figure out your drip irrigation? I am also trying to set up this system and asking the same questions