On the other hand, wood chips (along with leaves) are the #1 ingredient of great compost. (That's what makes up the forest floor.) True, they break down slowly using fungus in a process that can take a couple of years. Mixing some of the wood chips with coffee grounds sounds like a great idea. You will end up with a great soil amendment and more worms than you can imagine. Just don't add it to the garden until you have a crumbly earthy humus.

It's not really a question of which is most nutritious as which has nutrients that are more readily available and those are in leaves. If one looks at what Ma Nature does we would find that she uses a combination of leaves and wood to maintain nutrient leaves where she is in charge. The slugs appeared because you created an environment, cool and moist, that they like with that leaf mulch so yes the leaf mulch could be why the slugs appeared. However, they would have appeared if you used straw or anything else that would have created a cool, moist environment. kimmq is kimmsr

It is not the dye in dyed mulch that is of concern. Most of that is plant based and perfectly safe to use in the garden. What IS of concern is the wood used in dyed mulch. It is recycled scrap lumber - shipping crates and pallets, construction debris and similar "junk" wood, often contaminated with petroleum and other potentially toxic chemicals. And the fact that dyed mulch just looks so very unnatural. Mulch should be completely unobtrusive, not the most obvious feature in the landscape! Matching it to house color is never a consideration. There is also completely natural black or nearly black mulches available, usually compost based. This is what I use myself and also in clients' gardens - very dark, finely textured and richly organic.

@gardengal48 (PNW Z8/9), this is the chipper I have: https://www.amazon.com/gp/product/B077YDZ725/ It has a slowly spinning wheel with blades every so often. Older dry limbs get cut in to somewhat uniform chips, but softer or fresh wood is often mashed in to whatever it can push through. Worse, it constantly gets clogged up underneath, and then it just sits and grinds whatever is around the wheel until I notice and unclog it. That's where the smaller chips and dust comes from. My logic for mixing it with manure was to add nitrogen and organic matter to the red clay soil. Most of what I'll be planting are trees, shrubs, and tough flowers, but I'm also hoping to weave in some edibles (like habaneros) so I want to make sure the soil is fertile. Do you think that I'm just wasting time and energy by mixing in the manure?