So I've been searching for some information related to using wood chips in/around/under/on top of my garden beds. I've ended up here : ) . Lots of good information. I've read in another post that black walnut is toxic to most plants... which is pretty devastating news to me sense i have close to 10 cubic yards of chipped wood coming from various species native to Southern Kentucky. I know that Black Walnut and Red Cedar have been chipped in this mixture for sure. As far as the rest i do not know. i obtained the chippings from the utility company as they trimmed up the utility easement on the back end of my property. The pile has been sitting for 1.5 years. About 5 months after they dumped the chips i spread out about a 5" layer on my soon to be greenhouse floor (which at the moment was thick green grass). So about 1 year later the 16'x30' greenhouse is built (nothing growing yet) and a good amount of grass/random veg has growing through the chips. So I put down another 5" layer down. I intended on building some raised beds on the greenhouse floor (on top of the chips). Sense these chips contain Black walnut i'm kinda stuck wondering if I should rake out all the chips or just go ahead and built over top of the chips. Any advice related to what I have going on here would be greatly appreciated.

I found a resource that seems credible and promising.
http://ohioline.osu.edu/hyg-fact/1000/1148.html

Excerpt for the TLDR crowd.

Walnut leaves can be composted because the toxin breaks down when exposed to air, water and bacteria. The toxic effect can be degraded in two to four weeks. In soil, breakdown may take up to two months. Black walnut leaves may be composted separately, and the finished compost tested for toxicity by planting tomato seedlings in it. Sawdust mulch, fresh sawdust or chips from street tree prunings from black walnut are not suggested for plants sensitive to juglone, such as blueberry or other plants that are sensitive to juglone. However, composting of bark for a minimum of six months provides a safe mulch even for plants sensitive to juglon

Plant a few tomato seeds in it and see if they grow. If so, it is probably fine.

Welcome to permies matt ! Looks like Sabin found some good advise for you. Be sure to let us know how it turns out.

Thank you so much !! There have been so many "what ifs" during the slow process of this project. With this i can move forward! I'll make sure to submit updates for anyone in my situation or simply interested in what i'm building.
Greenhouse details: So far almost the entire project has been built from salvaged materials. I did have to purchase some 3/4" galvanized EMT. All the trees used in the build were dropped by the utility company. I came home one day to them going to town in my back yard and decided to snatch up the trees they cut down when they went home for the day.. All the wood used to tie everything together was salvaged from pallets. I've only had short periods of time to work on the project so the whole process has been taking some time. But i hope to have at least half the footprint of the greenhouse full of goodness this season!!! I'm always looking to incorporate new ideas! So please let me know if you have any or would like to suggest something!!

here's some pictures.

https://imageshack.com/user/Growyourown

I wish I had black walnut chips. I am going to plant a bunch of black raspberries. They are juglone tolerant and like mulch. I know black cherry is tolerant and I think onions corn and beans are. Juglone is the chemical that walnuts leach out. You may have a natural herbicide to build your mound out of. Check if the plants you want are tolerant.