Underground watering

I live in Denver. It is always dry, and now we are in the middle of another drought. More water restrictions and so on.

Watering under the ground, or at least, under the mulch, seems to make sense to me. Less water would evaporate into the hot dry air.  But is there a way to do this without it being an expensive engineering project?

I have tried using bottles with holes poked in the lid. In my experience, they either get clogged up, or empty out right away.

I have also seen expensive kits that regulate pressure and all that. For me, that kind of stuff is too big a deal.

Any ideas how to do this?

Try some diy ollas:
https://youtu.be/e7xckIcdBDA?is=XJWN4VsWClNQ7e-z

Have you ever tried that? I have heard of this, but I have to wonder: will it really keep plants watered?

I have a greenhouse raised bed/ container garden on legs at my mother's house where I use them.
The small volume of soil, plus the greenhouse covering conspire to make frequent watering needed, but the slow release of the ollas help a lot.

If you prefer,I believe  regular drip tape can be buried.

It occures to me that you might need  mulch, to lower soil temperatures and fight evaporation.
I am using ceramic floor tiles as mulch in one of my raised beds.
It seems to do great for alliums and greens.

Walter Byrd wrote: .....It is always dry, and now we are in the middle of another drought. More water restrictions and so on.

Watering under the ground, or at least, under the mulch, seems to make sense to me. ...

Just from some old experiences from central Utah through to Oregon and others in those climes will certainly add their own.  The canal system would deliver water locally and then be distributed into yards in many cases via flood irrigation.  Big operations clearly are still using pivot irrigation while others are using 'in-infurrow' where canal water is channeled between crop rows and allowed to fill the trough between rows.  For homestead type of watering where you are looking to conserve water, have you been watering more at dusk or at night?  That for sure can reduce rapid evaporation.  If I were living in that region again, I probably would set up the garden for in-furrow irrigation.  Plant your annuals in two adjacent rows and then make sure there is a trough between them that will hold water temporarily......usually adding soil to both ends to aid in the integrity of the trough.  To the extent that your situation allows, when watering, try to make the trough quite saturated with water and this trough can be covered with mulch to retain moisture.  Personally, even though I don't have proof for benefit, I like to give all foliage a quick spray of water as well, just to let them know that it just "rained".  This approach has its greatest effect when plants' foliage is large enough to begin shading the row--if you are just starting seeds, probably better to keep the seeds themselves moist and watered.  By day, the mulch and plant foliage will assist in reducing evaporation and with mid-season plants, their roots will easily be reaching into the furrow below ground.  Good luck!

I like to use soaker hoses.  

Soaker hoses probably would work well under mulch.

Maybe something like this:

https://permies.com/t/179957/good-idea-bad-idea-irrigated

Some good ideas here.

I already mulch. Although, I am not sure I do it right. I got a bunch of free mulch from the city. They put trees through a chipper and give away the mulch. Possible problems: 1. the wood is fairly fresh not aged. 2. the wood is in big chunks, some about the size of the palm of your hand. 3. there may be unwanted stuff in this mulch. For example, some of the mulch has these blue crystals, I am guessing something somebody used to try and dissolve a stump.

As to trench watering: I have small gardens, usually 4' x 8' or 3' by 6'. Would it still make sense? Also, I wonder how the roots of new sprouts will reach the water?

A drip hose might not be a bad idea.