OK, so today i logged on to garden but when i finished getting rid of there pest and needs it would't let me harvest them but when i logged on through my sister's laptop it allowed me to harvest them how can i fix it for my laptop?
Sometimes if you don't see the window that prompts you to harvest a plant you just need to move away from the plant and walk back up to it again and the window will appear. You might try that next time.
I've experienced this as well. However I didn't change computers. For me all it takes is exiting the game (not logging out completely, just returning to the character selection screen) and then going back again. It doesn't happen frequently, and I have not really noticed a pattern as to what's causing it.
I've also experienced another glitch that seems to only relate to the newest gardening spells, the ones you get in Khrysalis with 48 hour effects. What happens with those is after I've cast those spells, I harvest the plants, but the green ring indicating the plants can be harvested doesn't disappear. Sometimes it only affects a small number of plants, sometimes a lot, but it has never affected every plant. Same fix works though, exit and come back in, the rings are gone.