Buy RS3 Magic seed
The magic seed is the highest level tree patch seed in RuneScape 3. It needs level 75 Farming to use. Plant the seed in a plant pot with a trowel and water it to make a magic sapling. Then plant the sapling in a tree patch and it can grow into a magic tree.
This seed gives a lot of Farming experience. Planting gives 145.5 experience and checking the tree's health gives 13,768.3 experience. That is 13,913.8 experience from one seed. The tree takes 8 hours to grow through 12 stages.
A grown magic tree can be cut for magic logs at level 80 Woodcutting, and each log gives 365 Woodcutting experience. The tree regrows after it is cut. You can also dig up the stump with a spade to get magic roots. The farmer next to the patch will protect the tree from disease for 25 coconuts.
Magic seeds are rare. They come from bird's nests, dragon implings, the rare drop table, and the Evil Tree Distraction and Diversion. Buying magic seeds is a fast way to train Farming without hunting for these drops.