Question
there is a seed ball on the top of the plant, what is it used for?  planting? if so, do i just put it back into the soil?  thanks for your answer.

Answer
Hi Frank,
Thanx for your question.  The "seed ball" you describe is actually a capsule of bulbils.  The capsule will eventually mature and the bulbils can be planted to produce new garlic plants.  It will take 2 years to produce a decent-sized garlic bulb.  Here's a website I think you will find informative about this.  I hope this helps.
Tom

http://www.garlicfarm.ca/garlic-bulbils.htm