Question
8 days ago I planted many impatiens in a partly shady area.  They don't seem to be doing to well, and I'm hoping you can help! I live in Michigan.  The soil seems pretty good - more on the sandy side.  When I planted each plant, I added a little "garden soil" containing nitrogen 0.1%, phosphate0.1%, sol. potash 0.1%.  I watered throughly when planting. I planted them about 10" apart.  I watered them the first 2 days in a row, and then every other day.  We have also had a good bit of rain, and it has been fairly cool - not above 70.  I also put the cocoa shell mulch on top.  I have not given them any fertilizer yet - should I?  I am wondering if I am overwatering?    The leaves are turing yellow/white, and they just don't look well. The flowers are diminishing.  The stems seem weak and translucent; and some seem to break easily near the base.  I had some leftover plants still in the flats, and they look much better than the ones I have planted.  Any suggestions would be appreciated - thank you.  

Answer
My guess would be overwatering. It could also be transplant chock from being planted in too cool soil. My recommendation would be to hold off water, only watering if the top 1" of soil is dry. Next time you water, water deeply (not just a small bit) but then hold off watering again until the soil shows sign of drying again.

I would recommend that you keep the rest of impatiens in the flat until soil temperatures warm a bit more (a few weeks). Normally, soil temperatures are slower to warm in spring compared to air temperatures. While we may get fooled into thinking it is summer, the impatiens planted in cool soil knows better.

Do not fertilize at this time. It would only make matters worse.