Buy RS3 Carambola seed
The carambola seed is a fruit tree seed in RuneScape 3. You need level 113 Farming to grow it. Plant the seed in a plant pot filled with soil, then water it to make a carambola sapling. You need a gardening trowel to do this. The sapling goes in a fruit tree patch and grows into a carambola tree.
Planting the sapling gives 810 Farming experience. The tree takes 13 hours and 20 minutes to fully grow. Checking the healthy tree gives 35,057.9 Farming experience, which makes it one of the best trees for high level Farming training.
The tree grows carambola fruit in pairs. You pick two fruits at a time, and each pair gives 1,795 Farming experience. New fruits grow back every 40 minutes. The tree can give up to three harvests, for six fruits in total. Each harvest also has a 1 in 20 chance to drop harmony moss.
A farmer will protect the growing tree from disease if you pay 9 dragonfruit. The cost drops to 8 with the tree farmer outfit or 7 with the master farmer outfit. The seed is tradeable and stackable, so it is easy to keep in your bank.