Question
Kenneth,
HELP! I bought a beautiful impatent plant that was thriving  quite
well. Two days ago I fertilized all my vegetables and flowers with
Miracle Grow and today all its leaves are falling off. I am assuming
that I must have overfertilized. Is there anything I can do to keep it
alive?
Thanks, Joann  

Answer
Impatiens need very little fertilizer (light feeder) and applying too much fertilizer can be troublesome for them.

Water heavily to flush the root zone for a few days and then cut the impatiens back to a few inches of the crown. The plants should recover. Do not fertilize again for a few months.

If you use miracle grow (15-30-15) then use at half strength compared to vegetables. I like to use 1/2 tsp per gallon of water max and then fertilizer every 14 days with this mixture i/o heavily less often.

E.g. light feeding more often is preferred for impatiens.

Sorry to hear about your experience.

-- Kenneth