Pet Society: Meerkat the Auto Harvester is now at your service
For 4 Playfish Cash, Meerkat will take care of your garden (unfortunately, it's fruits and veggies only, no flowers) for 7 days, collecting all your produce, and keeping 'em fresh. An announcement for this service can be found in the game in the Garden store and the "Amazing Items" section of the Boutique store, where some extra ad copy informs you that "vegetables [are] harvested at gigantic stage ONLY!" This is good, because gigantic produce sell for higher profit.
To hire Meerkat, head outside to one of your gardens and you should see an icon on the left side of your game window. Clicking on it brings up the purchase window (as seen at the top of this post).