Just like sheets on your bed - a well made bed tucked in lasts -- at least for me in my part shade areas. In my full sun vegetable beds it doesn't seem to last as long & I need to reapply compost, manures in fall, mulch to keep my soil in good condition. Amounts vary, but probably 6-12" sheet mulched in fall after harvesting & 2-4" mulch applied after planting in spring sounds about right. If I heap on too much in fall I will remove some to other beds in spring that had crops growing in fall & missed the application. I haven't as much success with no till if I just layered on top of unimproved soil & didn't dig it in at some point down the road. SOunds like you've already double dug the area & added amendments for past 6 years. Your soil might be ready for no till. Different methods for perennials or annuals - vegetables or shrubs/perennial ornamental flowering beds. Earthworms do dig things in, but only so far. Seems like the moles also follow the worms & do their share of tilling in. In my raised veg beds where I don't walk on I don't till anymore - just dig in a bit of compost & some complete organic fertilizer with hand trowel when replanting (amount depends on the crop grown), add mulch when plants established. Some have been in use for just 3 years & others up to 20 years. The older beds are easy to dig with my hands. That's the difference over time & I don't dig there anymore other than how described above. Never used a tiller. Mostly the kids & I with just garden fork & shovel layering amendments in fall & turning in spring. Cost depends on what you have available cheap or free. Some ideas: -Raise chickens, ducks, or rabbits for nearly free soil amendments (have to buy feed & bedding for animals) -gather sweepings from feed store hay & straw mixture -try Craigslist for straw after Halloween, -wood chips from tree trimmers & let compost well before using -bag or contain pile of shredded leaves in fall to use in compost piles in spring with green grass clippings -call ahead to get a good amount of coffee grounds from St*rbucks -make friends with a horse rider. Horses can't eat hay that's spoiled, but it works fine in the garden. You can try it & always go back if you don't like it.

I sent the link to some fellow Arizona gardeners and one replied that it isn't as important here to have mature compost... supposedly the desert makes things different? Here is what he said exactly: eh, i disagree, if you are putting the right things into your compost, ie, not cistrus in this climate, you can use non mature compost no problem in az, if you burry it under your soil, it will decompose quickly and helps growth! this is supposing of course you are not box gardening, which is less than ideal here anyway, ive also heard this can be good way to revitalize "bad soil" in less than a year.

It hasn't yet. I've made three piles spaced about a month apart starting in Novemeber. None of them has turned to compost. THe first one was used horse bedding (with lots of wood shavings, a little rabbit manure, some plant waste and sawdust. It got to 130 and built back up to that after two turnings, then stopped getting hot. I left out the sawdust in the second pile, and it heated up ok, but lost it's heat pretty quickly too.I just mixed some chicken manure in it in hopes to get it hot again. The third pile was more random, with chicken offal, leaves, sawdust, and whatever I could find to mask the smell of the offal. Maybe they are getting too wet. Would being too wet affet the heat too much? Cuz these piles are COLD. How wet is too wet? Should I cover them from the rain?

Unless there is a strong urine or ammonia odor, the bedding should make a great mulch. Any strong odor would be high nitrogen and may burn some roots. Horse manure is rated 27:1 and can be composted straight or lightly mixed (25 - 30:1 is optimal) Here a mix calculator: Here is a link that might be useful: Compost Calculator