Huh, haven't found any difficulty in growing oversized crops. 4 Oversized ones plus 8 other crops, plus two trees it takes over two sims hours to 3 (without any gardening help from animals or using sprinklers)? With my sim having a high gardening skill is definitely takes less time.
I find the livestock to take much longer taking care of than gardening. Usually tend to the animals first then gardening.
Can always just hire a gardener now and again. Or just invite a neighbor, as high chance they're gonna tend your garden for you. Had a Sim's friend that lived in the city visit and after some chatting and leaving her to herself for awhile she decided to go out back to weed some of plants and water them.
Profit get. $$$
