A Weak naturalist's potion is a one dose potion made in the Dungeoneering skill. It is made by adding Sagewort and a Misshapen claw to a Vial of water. This requires level 30 Herblore and grants 72 experience in Herblore.
Using the potion boosts a player's Cooking, Farming, Herblore and Runecrafting by 3 + 2% of levels. The boost is just 3 for skills under level 50, and from 50 upwards the boost is 4.