If your plants are suffering from temperature changes, neglect, or mineral salt build up, try FoxFarm Bush Doctor Boomerang Comeback Formula! This immediately available supplement helps support the root zone with soil microbes. Can also be used as a vegetative supplement. 2 - 0.2 - 0.3 (2 nitrogen - 0.2 phosphorus - 0.3 potassium). 1 liquid pint. Always read and follow label directions. 

What is the coverage area?
In-ground and container plants: 2-4 tsp. per gallon water. 
Hydroponic recirculating systems: 1 tbs. per gall fresh reservoir water.