1/2 gph for how long? How big are the plants? What kind?

Tomatoes to do well it is best that they be kept at a relatively even moisture. With your mix most of the water will be removed by the plant, the bigger the plant the more transpiration, also the more heat the more moisture needed to be replaced. From your post I can not tell whether you are in Texas or Alaska. Generally speaking drip works well for container grown tomatoes. Al

You should test it out.

Just drip into a tote of your mix, starting with the mix dry.

See how long it takes to start dripping out the drainage holes. That's how long you probably should set your timer for.

Also check to make sure the water diffuses to the entire mix. Peat usually diffuses water well, but with just one emitter it might not be enough.

I had 5 emitters in a 18 gallon tub and a fast draining mix. The water did not diffuse enough and about half of the mix remained dry, not matter how long I watered for.

I dump prior season's mix and throw some additional materials in it but always make sure that it is moist before going back in tubs.

I agree with calistoga once roots start to fill up the container they will suck up the water.

I am going to use (2) 1/2 gph emitters for large tom a 1 emitter for 12 inch containers of chile peppers. I will also g3t some cheap ball valves in case I want to reduce the flow.

Also remember that you can buy different types of emitters that have greater spreads. Even micro sprinklers that will give you a fine mist.

If you are absolutely trying to minimize wasted water then maybe some mix of button emitters will work but were I setting up a drip system for convenience I think I would go with some type of micro bubbler or maybe even a micro sprinkler in each pot just to make sure I had good coverage. But I'm a complete amateur so take that with a grain of salt, heh.

For my larger containers I use what is called "spitters" plastic spikes that stick into the soil about six inches long. A 1/8 inch tubing attaches to the top which has a calibrated slot that caused the water to spit out. They are from 4 to 8 gallons a hour. The plastic color indicates the gallons per hour. Nurseries use them for their container stock, and when a container is sold, simply connecting to the reverse end of the stake stops the water until another container takes the spot and is reversed again. I buy mine from www.harmonyfarm.com Al

Oh! Al, I have a question about those. I'm trying to rig a drip system for my container garden in case I have to be away for a few days over the summer. I have quite a few plants in the gritty mix and I don't think the usual drip heads will cut it with that mix.

The only ones I've been considering are the C 45 degree down sprayers and the spitters. I've seen the C sprayers in action and I'm sure they will work - the only problem is that they all have very high GPH which means I will either need 2 zones one for the gritty pots and one without - or I just have to deal with a ton of overwatering into the gritty. Obviously that isn't the end of the world since it's the gritty mix but I'd like to avoid it if possible.

I have NOT seen the spitters in action. I can't find a video anywhere. Do they spit in a straight line? Is it a radius? Will they cover most of the pot and work for a gritty mix with essentially 0 wicking properties?

Thanks!

redshirt the spray is horizontal with a path of between 90 and 180 degrees. The spray at normal drip line pressure is about one foot or so if you do not push the stake too far into the soil. I can take a photo of one in action(no not an action photo!)if you email me so we don't bore others here who are not interested. Al