You have to buy some fruit or veggies at the grocery or market first. Then go home and look at your sims' inventory, you should have the fruit/vegies inside. Click on it and you would see a action as <plant>. Click on plant and choose a spot in your garden. Water it daily and tend your plant when it has weeds. You should soon have the icon <harvest>. Enjoy your results and try to cook with them! They can upgrade the food's quality!
Chat with our AI personalities
You can buy them at the supermarket, or, if you have a watermellon or watermellon seeds, you can plant your own.
You have to plant seeds. at first they can only plant a few, like lettuce seeds. as they gain skill looking after them they can plant different types of seeds. the seeds can be found on the ground or there should be some in your inventory. You will have to make sure you keep tending the plants or they will die.
the cow plant is only in the sims 2, you can not get one in the sims 3
Supermarket.
you dont have to find the bamboo seeds, just chop some bamboo down and then plant it in a soil patch hope it helps! :)