No.
Based on the craft rules you pay a certain price in silver and craft the poison.
As a GM, at best I would let you make a knowledge nature check in place of a craft check to "produce" the components required to make poison. Mechanically it would work exactly like craft to produce a good except there would be no price to pay. This would represent finding reagents as you explore. When you had sufficient value accrued you could then craft a poison without paying the silver cost which theoretically represents the cost of raw materials. However, that is completely house rules.