Hello, I am wondering if any of you have amended your dirt before landscaping a new construction lot? I'm talking about adding phosphorus, maybe chelated iron, microhizal fungi, ammonium sulphate, etc. I had a soil test done and I'm high in nitrogen and potassium but very low on phosphorus and my pH is 7.7. Our lot right now is just plain fill dirt brought in by the builder for grading. We are going to be finishing our landscaping this summer. I'm planning on doing about 50% kentucky bluegrass (lawn), and the rest a small fruit orchard, raspberries, vegetable garden, various trees and perennials. I'm definity adding several tons of compost, so I know that will help but I'm more wondering about the other stuff. I've heard contradicting answers and wondering if any of you have an opinion or experience of this?

If it were me, I would amend, but go easy on the ammonium sulfate. Then add the compost, wait a bit and then retest. I think it would be best to be conservative, retest and then amend more rather than add too much of something and have to try to correct it.

If the soil test was done by the university, they will normally include info as to what you can add and how, for the nutrients which are deficient.

especially about the sulphate. Keep in mind that just because its planted doesn't mean your cut off from doing anything else, its not a one and done. Topdressing and aerating will amend the soil in an established lawn and mulching and or topdressing will do the same for an orchard or berry patch as well, but there a broadfork would be the tool of choice.
Elemental sulfur in your garden area would also be a good idea just to bring down the ph level and can ( should ) be mixed with your compost, this can also be added in an as needed basis...anywho...

Congratulations on your new house and best wishes.
J.R.

Ditto what JR said. The soil at my condo was not that great when I moved there, but I just keep top dressing it. My first clue that things had improved was when I started seeing an increase in earthworms - just like a forest floor, it is a continuous work in progress.