in the cooking guide, there is a chart that shows an apple, cabbage, cheese, garlic, pineapple, red berry, and tomato, and it shows where they spawn.

 

 

 

for pineapples, it only says they are obtainable in brimhaven, but they are also obtainable from ape atoll

Also, on Catherby the General shop owner sells you 40 pineapples a day for 2gp each, his name is Arhein. This is noticed in the Farming Guide though!, and you can Farm Pineapples yourself!

Thanks both, added.

 

 

 

The Farming note (step 2 of Garden Produce) says that players can grow their own fruit trees and includes a link to the farming guide.