ken:

They don't need fertilizer if they are growing at least 12 inches a year and have enough foliage to shade the ground. Excessively vigorous trees reduce eating quality of the fruit. I think your gut response is right here. But I go by how the tree looks. Don't need a soil test unless it's an initial baseline or if there is a problem.

well .... the two i planted last year.. 3 foot sticks ... put out about 2 feet of growth ...

so there you go ... leave well enough alone.. go figure .. lol ...

ken

Fruitnuts always advising against too much N because his focus is on getting high brix on bearing age trees. Funny thing is I was in agreement with him but someone questioned the veracity of my claim that too much N reduces brix and all the research I could find didn't really back up my or Fruitnuts claim.

Maybe Fruitnut can help me here but research I saw showed no affect on brix by varying rates of N. It's about water which Fruitnut also cuts back on to get highest quality fruit.

Anyhow, forget fruitnuts advice if what you're trying to do is size up the trees quickly. In most soils some supplementary N will help do this.

In your soil I'd recommend a split application- one now (the frost won't hurt at all) and one about 6 weeks later.
Maybe 2.5 ounces actual N per 100ft square each application. If you want to keep cost down the stuff you already have will be fine, but you don't want to continuously be adding P without knowing whats already in the soil. It can build up over time and create problems of imbalance.