Fertilizer???help!!

[MrUPS]

Hey guys just a quick question, I am a new guy to the buisness, and I have seen the difference between not fertilizing and fertilizing, I know it is late in the season but is there a fertilizer I can put on the lawns to thicken and green them up???
Thanks
Rob

[lawnstudent]

Read the "Potassium qty & timing" tread and please do a search. Thank you.

jim