Many people don't till at all. They put amendments on top of the soil and let the soil microbes and worms work them into the soil.

For an area of that size, if you wanted to till, you could probably do it with a garden fork. If you decide to till, it probably makes more sense to add the amendments first, so they get mixed in as you turn the soil.

It's probably not a good idea to till too close to the lilac, and moving it and putting it back wouldn't be doing it any favors, either. I would avoid the area in the immediate vicinity (at least within the drip line, an imaginary line around the plant that is defined by the outer reach of its branches). I wouldn't think you'd be planting in that area, anyway, though.

Good advice on everything, but if you're adding amendments, they should be mixed in with the soil, where the roots can use the nutrients. Laying them on the surface is fine IF you're going to put mulch on top, and IF you don't need those nutrients for a year or so.

Sue

Actually, if you put them on top and depending on your soil, a year may be minimum, even with your sand.

I put good manure compost and mulch on top of a blackberry garden I planted and a year later when a few of the plants had died I dug them up and was astonished to find under my compost and mulch, the same soil. It had not even changed color.

Ever since mixing amendments into the soil I have not lost a plant. Most of the time now I'm not even mixing in compost. It's just vegitative waste live shredded leaves and grass, and a make the beds much larger than needed mixed in with a tiller.

Just my .02, good luck!

My experience with Lake Michigan beach sand is that tilling organic matter into the soil will never get any level of humus into the soil. The only way I could get reserves of organic matter, humus, to build up in this sand here is to put the OM on the soil as a mulch, not till it in, and maintain that mulch. Tilling, expecially in sand, introduces large volumes of air that apparently stimulate the soil bacteria to rapidly digest any organic matter in the soil.

I have a question. Do you currently have grass growing on this area? If so, how are you planning to remove the grass? Also, BEFORE you start adding all of the soil amendments (which is a great idea, don't get me wrong) maybe it would also be a great idea to have your soil tested in order to find out just what kind of soil you are dealing with. Is it acidic, neutral or alkaline? That question alone could change the kinds of amendments you use, depending on what you want to grow there. Also, what are the current values for nitrogen, phosphorous and potash? That will tell you a lot about how much you need to add, and if you should also add a bit of fertilizer. If you have a local home extension agent, that would be a great place to start in terms of getting your soil tested. I have also used those home tests you can purchase, and have found them to be reasonably accurate. And I would do more than one test, if I were doing it myself, just to duplicate my findings and make sure they were correct. (Testing soil isn't my area of expertise! The first time I did it, I got it all wrong!) One point they make in the Master Gardener course is to check more than one area, since the composition of the soil can change over a relatively short distance.

I grew up in Michigan, and we had a HUGE garden (actually it was more like a small farm). We raised chickens and used to till in their used bedding every spring AND fall. Eventually, we had pretty decent soil. Good luck!
MacThayer

Kimmsr: "Tilling, expecially in sand, introduces large volumes of air that apparently stimulate the soil bacteria to rapidly digest any organic matter in the soil."

You're right, that fact has been scientifically substantiated. But they say if you do need to till, only go over it once, don't keep doing it. Some people think they need to turn the soil into a talcum powder consistency, when the reality is that if you till OM into it and leave bits sticking up, it helps draw the rain into the soil, instead of having the soil's natural surface tension (if it's dry) repel the water.

Sue