Buy OSRS Tarromin seed
The Tarromin seed is a members-only Farming seed in Old School RuneScape. You can plant it in a herb patch at level 19 Farming. When the herb is fully grown, you can harvest grimy tarromin. Cleaned tarromin is used in Herblore to make potions.
Each patch needs one seed. The herb takes 80 minutes to grow, in four stages of 20 minutes each. Planting gives 16 Farming XP, and each herb you pick gives 18 XP. The plant does not regrow, so you plant a new seed after each harvest.
Each patch gives at least 3 herbs, and often more. Compost adds one extra harvest life per tier, up to 6 with ultracompost. A higher Farming level also raises your chance to keep harvest lives, so you get more herbs per seed. Magic secateurs, the Farming cape, or a growing Attas plant can boost yield too.
Herb patches are not watched by gardeners, so the crop can get sick while it grows. Plant cure will fix a diseased herb. Tarromin seeds are tradeable and stackable, and they weigh nothing.