To see what Greenfield Citrus Nursery has to say about fertilizing citrus in Arizona just follow the link. http://www.greenfieldcitrus.com/grow.htm As far as foliar feeding goes it can be helpful in keeping the leaves green. The seaweed and fish emulsion also helps prevent damage from some pests. The vinegar in a foliar feed I don't think is advisable. Vinegar is used to lower ph in soil by adding it to the water you water your trees with. Vinegar is also used as a herbicide and can kill plants and leaves if sprayed on the foliage in high doses. Our water company is SRP and spraying the leaves often with water where I'm at is not advisable because our water is hard. The hard water deposits can build up on the leaves and damage the foliage. A few drops of vinegar per gallon may prevent the deposits from accumulating. Is that why you are using it?

Nitrogen draw down is a significant problem for your vege patch that contains 'hungry' shallow rooted annual, biannual and short lived perrenial plants. But even here you can compensate by liberally sprinkling blood and bone over the soil surface before laying the green mulch.

I am a firm believer in mulch, especially in our state that is plagued with drought. I put about a 3" thick layer of mulch to within 2" of my tree trunks. I haven't seen any root rot issues and I water daily in the summers due to my temps that can climb to 120 degrees in July/ august. It will also help keep your roots warm during cold spells in the winter, my in ground trees usually see a couple weeks in December -January with lows in the upper 20's and they don't show any signs of damage. Here are a couple pics of my mulched trees earlier this year. Rio red grapefruit Oro blanco grapefruit Cara cara navel orange Key lime tree Evan

Here is the UF page on Citrus Growing in the Home Landscape. It's a good reference overall for growing citrus. If you don't like weeding and don't like chemicals, maybe you should not grow citrus. No tree should have mulch up against the trunk. In FL, if there is grass up against the trunk, yard crews tend to damage the trunk with weed whackers. Just something to think about. I've used vinegar to kill weeds before, and it works well, and doesn't harm the trees. Chemical weed killers are not absorbed by the roots of the trees if used properly. They are burnback products that kill the above-ground portion of the weeds so that the roots die. Unless you pour a whole bottle of it around a citrus, you won't get chemicals in your fruit. This is what UF says about mulching: Weed Management Often, citrus trees are planted in the midst of an expansive green lawn. Complete weed control is not essential, but weeds and sod grass should be removed from the area under the tree canopy. Above all, make sure all weeds are removed from the area adjacent to the trunk of the tree. Such weeds could promote injury due to a soil-borne fungus known as foot rot, which can seriously debilitate or even kill the tree. Mulches are not recommended around citrus trees, but if trees are located in a cultivated plant bed where mulch is used, it should be kept at least a foot away from tree trunks.