Only doing palm trees, because they're cheap and fast. Like 30m max for 90.
Teleport to camelot.
Run EAST to CATHERBY PATCH.
Run NORTH, take glider to grand tree.
Run downstairs, and SOUTH, to the GRAND TREE PATCH.
Spirit tree to GNOME VILLAGE PATCH.
Teleport to ardougne, run SOUTH EAST to take boat to BRIM PATCH.
2 water runes, 3 law runes, 5 air runes.
4 palm tree saplings.
60 papaya fruits.
5 patches per day = 10509*5 = 52,545xp per day.
2,007,823xp to get = 2007823/52545 = 38.2 = 39 days.
Seed = 105.6k
Payment = 1318*15 = 19770
Total = 125,370 per seed.
Gp/xp = 125370/10509 = 11.9gp
This does not include the fact that I will get 6 coconuts from each tree, which can be sold to reduce my costs.
2007823/10509 = 191 seeds = 20.1m
191 * 15 = 2865 * 1318 =
Total cost = 20.3m