On free wood chips: I have been using wood chips as mulch for a couple decades, and I have not gotten any insects that weren't already around or diseases. The tree companies are working in your immediate area, so anything that's in the chips is probably already in your yard (or your neighbor's yard). The worst thing that happened was getting some wintercreeper in a load and not realizing how awful it was soon enough.

Best way to amend clay is to work in compost. Those chips will take forever to decompose and make any difference.

What problem do you see with the clay soil? There are some particular types of clay soil that cause problems (very hard and dry or poor draining or turns into thick mud) but there's nothing inherently wrong with soils with clay. If what you really want is super-loose and fluffy soil, that's fine, but it's not that clay in soil is inherently problematic. As shown by stuff you have growing there.

And since you have two or three years, pretty much any approach is going to work. It's up to you which works in terms of work/cost/what you have available and what you can put up with in terms of how it looks. Tilling in or digging trenches and burying will obviously provide more of an obvious bed area and get you down (a bit) deeper; advantage in burying is you can add stuff in almost any condition. So mainly, add as much organic matter as you can. You may want to put thick mulch and/or some cover crops as otherwise weeds will grow in.

If you have some specific concern, you could get a soil test, but whatever it tells you may not apply after adding mixed organic matter (especially for eg nitrogen in soil that leaves soil relatively quickly). Will also depend on local conditions - esp how hot and dry it is in your location. I have no problem with wood chips breaking down over time, but may want to mix in 'greener' compost materials or manure, depending on the wood chip materials' condition too. But mainly, adding lots of organic materials will enhance the soil life/soil food web and that'll be good down the road.

I would suggest you add manure because you can use the garden immediately instead of waiting for years. Google "horse boarding your town and state" to get a list of these facilities in your area. They usually will be thrilled to let you haul off as much as you need. Rent a pickup if you don't have a truck or trailer.

You would usually want to haul off the oldest manure as that's already well composted. However if you want to use wood chips you already have you may want to take the newer manure as the extra nitrogen will balance out the wood chips tendancy to suck up nitrogen while decomposing.

I know a couple of master gardeners who did just what you proposed with wood chips - spread them around, but don't dig them in. I have done some of it myself. It does not take forever for them to make a difference... The fines decompose in a year and all but the largest pieces are mostly decomposed after 2 years.

Any amount of compost or manure you dig in will have dissipated after 2 years and will need replacing.

Thanks everyone. Good suggestions, and i learnt some more (though i scoured internet for hours on this topic). To answer some questions......

• The soil is 90% semi soft clay for about 8 to 10 inches. After that it is hard clay, and i have to use a heavy digger, to make a dig of that. So, i have been only working with top 12 inches or so (while creating my raised bed area last year, which got compost put into the hole along with hugelculture). The raised bed is giving phenomenal tomatoes this year, compared to my 30 gallon pots last year.
• The weeds spring up year after year in the exposed soil, and my gardner used to take care of that in spring time only. Now, i have stopped him, and i am taking care of the whole backyard, since he wasn't doing much anyways. The weed/ soil area that i want to control and make usable is about 25' x 14'. I want to leave the edges for walking, and the remaining 23 ft x 13 ft is what i can use for vegetable gardening. Surrounding this area are some fruit trees, a rose and some shrubs.
• I have my raised bed for this season, and can not do more (since i am newbie who is learning at this stage). But, i want to prep this soil for use in few years more. So, after watching some worm tower ideas on youtube. i am thinking of installing a few of them spread around this area, since i get lot of kitchen waste every week and i need to dump it somewhere. It sounds like i can control the weeds with either free horse manure or free woodchips (which seem to carry a bit of risk).
• The other idea (instead of worm towers) is my prior success with trench compost burial. I can dig few trenches (spaced out in the 23 x 13) and dump my kitchen waste over next 1 year into this trenches for composting. Within couple of years, the earthworms will prep the trenches for me to plant in.

The other problem i am having is ants throughout the soil. Not really seeing big anthills or seeing them in numbers, but just enough in my raised bed to get me wondering about controlling them. At the same time, i am also seeing many insects in the soil, so i am inclined to leave everything as nature, without putting any chemicals into the soil for controlling insects / ants. Would like to hear your comments on this too. Thanks.

I agree it’s not an either or situation. Mulch all over with wood chips. Pull some mulch back. Dig your trench. Fill with compostables. Cover it over with soil and pull the mulch back over. Proceed thus down the plot.

I have dug a few inches of horse manure or mushroom compost into my clay the depth of the spade. I usually dig the area twice. I cover the soil and the sod with a couple inches and turn it over. When I finish the area I spread another inch and turn the soil over again.

On the same day I have transplanted my heirloom beefsteak tomato seedlings into that plot. I get huge delicious tomatoes, lots of them. The plants grow 7 feet tall and very lush. Last year I covered the whole tomato area, 22 plants, with 2 year old wood chips. It's my opinion that while you can garden immediately that my clay soil still needs improvement by adding organic matter. My original garden after 15 years is almost a loam soil.

My main point here is that when you want to garden it's nice to see immediate results, a least in the first year. Improve that soil while your also reap some rewards.

John, the above sounds like the "double digging" method that i recently saw on youtube. Great suggestions, everyone, thank you. I am looking forward to burying that compost somewhere in garden this weekend, since maggots have started, and i do not like to lose all nutrients of compost to maggots. last year, it was a nightmare, because almost a 30% of my compost turned into maggots that i had to bury. dont want to suffocate them this year :-)

Maggots in compost are usually soldier fly larvae and they are good thing. They are just one of the myriad of OM decomposers. They help to create nutrients, not to consume them.

Sam - Some refer to "double digging" when you dig double deep.

Yes. Double digging isn’t just digging twice. It refers to a specific technique.

The electric utility where I live gives away chips, and they have told me their crews avoid chipping anything that was already dead or diseased when they are trimming. Note their primary purpose is to keep the electric lines clear, not simply to trim and remove trees as a tree service would, so they don't see as may dead and diseased ones. Call your electric utility and ask what they do with the chips and how they keep diseases and invasive plants out. Wherever you get them, if you can get wood chips in summer, they have more leaves and green twigs which have more nutrients than dormant woody branches.

To passively build up a bed, I like to put compost or nearly compost material on the bottom, and less composted stuff on top. If I was you I'd get that manure if you can find some, layer that down a couple inches deep (or more), then add wood chips several inches deep. When you have kitchen scraps, dig a hole or trench into the soil, add and cover back up.

The worms and microbes will have a field day with this delicious layer cake.

This may be helpful: The Myth of Pathogenic Wood Chips. Pay particular attention to one of the key "bottom line" statements - • Do not amend soil with wood chips; use them only as a topdressing