I can't be bothered actually checking what you can do at level 25, but anyway. If you want a cheap way, and I think the best way to do it, do allotment. All allotment besides strawberry can be done with a 0% chance of dying, if you put the right stuff in the flower patch. For example, if you're going to grow watermelons, put in nasturtiums. Once they're grown, your watermelons have a 0% chance of dying, As long as you keep that flowers in there. If you're doing sweetcorn, put in a scarecrow, etc. Always use supercompost. Always use magic secateurs when harvesting. With the combination of both, you get tonnes more items from allotment + herb. Anyway, my suggestion = Grow the highest level allotments you can, along with the flower that goes with it, in each patch. [Ardougne, Catherby, Falador, and Port Phas.] You can do herbs as well if you want. They're pathetic exp, but good enough if you want to do herblore.