ok dude key thing.....TO MUCH FERTILIZER! you can over water a plant but for first timers thats pretty easy to do and over time you will find the perfect times to water your plant(its kinda like a rutine you will get into)...but remember that plants do obsorb most of their water through their leaves, so if they are not out side you need to keep them misted. every morning and night. now temperature you need to watch...anything above 85 is usually to hot unless they have been started and grown OUT SIDE the WHOLE time then your plants will adapt to the high heat of the summer. now back to the fertilizer...if you are using a potting soil that has fertilizer in it then you dont need to fertilize just yet. most potting soils will feed your plant up to three months. after about three months then you should start to use a fertilizer...now i have worked with maricle grow before and it has a tendency to "Burn" your plants which is what seems like is going on with yours. so BACK OFF with the fertilizer for a while. just give them straight water about every 7 to 10 days and see how they do...after they make a full recovery then you can fertilize...but induce the fertilizer very slowly...just giving them small doses every other watering and gradually work your way up to a higher dose of fertilizer.