Buy RS3 Acorn
The acorn is a Farming seed in RuneScape 3 that grows into an oak tree. You need level 15 Farming to plant it. First, plant the acorn in a plant pot of soil with a gardening trowel to make an oak seedling. Once it grows into a sapling, plant it in a tree patch.
The oak tree takes 160 minutes to fully grow. You can pay a farmer one basket of tomatoes to watch the tree and stop disease. Planting the seed gives 14 Farming experience, and checking the grown tree gives 467.5 experience.
Once the tree is grown, cut it down with a hatchet to get oak logs and Woodcutting experience. If you leave the stump, the tree will grow back. If you dig up the stump with a spade, you get oak roots and the patch is cleared for a new tree. Oak roots can be used in brewing, so they can be worth good money.
The acorn is a great pick for players training Farming at low levels. It also works in a trough to make seedy mush or variety mush. It is a members item, but it can be obtained on free worlds.