Buy OSRS Elkhorn coral
Elkhorn coral is a Farming item in Old School RuneScape. Players grow it by planting an elkhorn frag in a coral nursery. The nursery is an underwater spot near the eastern coast of The Great Conch. You need level 28 Farming to grow it. The coral takes 160 minutes to grow and gives at least 4 coral per harvest. A nearby gardener will protect the growing coral if you pay 5 giant seaweed.
Elkhorn coral has some handy uses. With 49 Herblore, you can use 5 crab paste on one coral to make 15 anti-odour salt. This salt is used up on its own when you set hunter traps to smoke them. The coral is also the first step in making haemostatic dressings. Add it to a vial of water to make an elkhorn potion (unf), then add squid paste and cotton yarn.
You can also use 5 elkhorn coral as payment to protect pillar coral. Planting gives 20.5 Farming XP, and each harvest gives 24 XP. The coral does not regrow, so you must replant after each harvest. It is a light item and weighs only 0.028 kg.