Those dead brown patches and leaf edeges look like sunburn. The irregular discoloured blotches look like overwatering. Try to maintain constant temperatures and keep the soil moist but not wet. They will need to be moved into the sun gradually if they are not used to it. Avoid temperatures below 40F and certainly protect from any frost.

It sounds like you really went to town on the phosphorus, although I couldn't calculate exactly how much you put in. That may not be helping. Impatiens, even New Guineas, don't need a lot of fertiliser.

My understanding is that impatiens don't especially like alot of fertilizer. The NGI are supposed to be sensitive to high salt levels. If you have adobe, check out the attachment, especially the section on fertilizer. Chris

Here is a link that might be useful: NGI growing tips

I think it is most likely sunburn--this is exactly what my palnts look like when I've ben "uncautious" with putting houseplants out or not hardened seedlings off gradually to light conditions. I live in Seattle, which is a somewhat higher latitude and not too bad for sun damage usually, but if your plants have been accustomed to growing in the relatively low light of an indoor situation, putting them outside under shade will work best initially. The other thing is that they may not be able to grow in sun at your location. What you have looks like the New Guinea variety, which I have found to be very delicate in terms of sun exposure and water needs, despite the pronouncements to contrary I've read.

The former comments are correct. This person has the New Guinea variety which is SO very picky, I will not mess with it. They are TEMPTING as they offer such a bright array. But I would spend my SAME dollar on the normal Impatiens, never too much sun, planting in shady area's mainly, and I REALLY prefer the Double Blooms that appear like roses. I bought ten of both last month and the Double Blooms, same price, had very little mite issues. I did find mites LOVE the single bloom, and I am on thsi site today to find out why in another forum. I love Impatiens as they bloom year round and you can eat the petal in gourmet salads as long as you have not used pesticides. I swear it is double bloomers from here on out. Then you can propagate what went very well.