I might try posting this in one of the other forums where people know more about lasagna method.

You'll notice that the utah forum is not the most frequented.

I grow in the native soil. I try to mix compost into my soil and plant into that. I also try to add organic material on top of the soil as a mulch to keep it moist in the summer.

I know that some people have been successful in straight compost (or close to). The thing that worries me most about your description above is the layer of cardboard. I think (guess) the cardboard will take several months to decompose to the point that roots will easily penetrate it. I would be more worried that your plants will never be able put roots down as deeply as they would like than I would be about your compost. Also, your irrigation/watering will not sink through the cardboard very well. but will pool on the cardboard or stay in the compost and the roots of your plants good get a bit swampy (why the ext. probably recommended backing off the water).

I realize that I am too late to offer useful advice but if it were me i would do (would have done?) one of two things:

Either plant your plants into the soil as you have created it but cut through the cardboard underneath them underneath the plants and in several other places (just cut tears or slices so the roots can easily get through and the water can drain) and see how they do. They'll probably be fine. And your soil will be awesome next year.

OR remove the cardboard and mix all of your amendments into the top 6-12 inches of the soil.

Anyhow. Sorry I don't check this forum very often. I Hope your garden is fun and fruitful anyway.

I live in PG and am a new gardener but have a big garden and the benefit of very experienced gardeners giving me pointers and advice.

JP