A nearby gardener will not watch over your growing fellstalk. Fellstalk seeds can be obtained as a reward from Evil trees, by pickpocketing Master Farmers, or from Managing Miscellania. They are also part of the Rare drop table. When planting the Fellstalk seed, it is recommended to use Supercompost (or Fertile Soil spell) in order to maximise the potential yield and to reduce the chances of a disease. The following table shows the profit yield, assuming all the herbs and seeds are purchased/sold at the Grand Exchange, for the guide price. If the herb dies, you will lose coins.