Plant Food Spikes

N/E body here ever used plant food spikes (ie. Jobe's, Miracle Gro, etc.)as their source of nutes? If so, what kind of results did you get? The reason I ask is b/c I'm experimenting with using those. Also should I pull the spikes out when just about ready to harvest, should my plant be a female, or can I just leave them in the dirt? Thanx in advance.

seems like they would be hard to control. not sure of the nutes either.

I don't like fert spikes for the same reason I don't care for any soil with added time release nutes...
I like to be in control of my plants diet!