How to train your farming skills in runescape

In runescape, seeds are usually easy to obtain. They can be bought from players and stalls, stolen via Thieving, obtained as drops from an enormous variety of monsters, and are rewards from the Vinesweeper minigame. Any lower or intermediate level seed is usually extremely cheap, ranging from 1-20 coins each, while the higher level seeds, such as tree, fruit tree, and especially upper end herb seeds, are usually thousands of coins each, if not more. You can sell the items in game, then get some runescape gold as return.
Although this would seem to imply that players can simply plant their seeds and go back to their lives, there is a problem with this tactic. At lower levels, unattended crops are extremely unlikely to live long enough to reach maturity unattended. Even at relatively high levels there will always be a significant chance that crops will sicken and die. Therefore, all levels are recommended to pay nearby gardeners to watch crops. Doing so prevents the selected crops from dying, thus guaranteeing their reaching maturity for harvest.
After growing for a pre-set period of time crops will mature and can then be harvested, provided that the crops have not become diseased and died while growing. Once planted, crops grow even if the player is not online, so one can plant a seed and come back at any time. Once the crops are fully grown they will remain in the patch indefinitely until harvested; that is, they will not die once fully matured.
Gardeners all charge for their services, but not in coins. The price that they ask depends on the crop that the player asks them to watch. For example, the price for protecting a patch of potatoes is 2 buckets of compost while the price for protecting a patch of onions is 1 sack of potatoes. Unfortunately, Gardeners will not watch herbs or flowers. Players can, however, unlock a single herb patch which is perpetually protected from disease, for free, by completing My Arm's Big Adventure.