Whatever is cheapest in your region.

Most regions the cheapest is arborist wood chips which are usually available for free. Here's a little info on the subject.

http://www.puyallup.wsu.edu/~Linda%20Chalker-Scott/Horticultural%20Myths_files/Myths/magazine%20pdfs/Woodchips.pdf

Wood chips ...wood chips...wood chips... free and they suppress weeds, add nutrients over time, conserve water, etc etc... I've used them for over 6 years now. Only problem I see is you have to reapply about once a year, at least in my climate.

Actually, I think over time there may be the problem of over enriching your soil and that it may not be a sustainable system for weed control in home orchards in the humid regions. Where it rains during the growing season you can't simply reduce irrigation to reduce vegetative vigor.

I actually have a Red Haven peach that has produced low sugar peaches for the last 3 years running. This weekend I'm putting down temporary plastic sheeting in hopes of deflecting enough rain water to get the brix up. It produces the biggest, most beautiful peaches you are likely to see. I suspect other of my peaches have lost some of their sugar as well but they're all still quite good.

This isn't to say that mulch isn't great for establishing trees but once they become bearing age there may be a price to pay for continuing to mulch generously.

My climate tends to be very dry from about mid June - Sept. and is anywhere from 100 - 80 during that time. Most of the rain falls in the Spring time. My strategy is to avoid irrigating if possible so the wood chips make for a good water retention mulch. Wood chips don't eliminate my need for weed control but they certainly reduce it and retain soil moisture.

My guess is you are in a much wetter climate than mine and closer to Harvestman's, beware retaining too much moisture. Keep in mind that some tree root systems don't like "wet feet".

Learned the hard way that mulching with too many grass clippings can cause a dry, rain impervious layer of mulch to form that causes virtually all overhead water to be shed off of it.

Arborist wood chips don't stop rain, that can happen when they're double hammered (look shredded). They don't generally cause wet feet either and instead allow roots to function in more aerated soil right at the surface that would otherwise be to hot and dry or occupied by competitive weeds. The worm action also creates a well aerated honeycomb affect.

Apparently wood chips will stop most weeds when spread at a 4" depth but that can require an awful lot of hauling in even an average sized orchard if you do 6' rings. I think about 4 large wheel barrows per tree.

Does anyone know of a source of wood chips in the St. Paul, MN, to Eau Claire, WI, area? Northwoodswis

Look up tree care. Tree care co's are always looking for places to dump the stuff. The only problem is that only well maintained machines produce the nice chips without a lot of strips. Strips look ugly, but more importantly, make forking the stuff a forking pain in the butt.

michael357
it is hot and dry here for the summer so water retention is important here too