Much of the produce in grocery stores has been sitting in the store's back room, on trucks, or in wholesale warehouses for weeks to months! Grocery Store tomatoes(even so called vine ripened) are picked green so they are firm and pack well and then dosed with ethylene gas to mimic ripe fruit flavors. The only way to know what a tomato(or cucumber, potato, strawberry, or watermelon) really tastes like, is to grow it!
Cucumbers, onions, radishes, tomatoes, chilie peppers, and herbs can add up quickly in a store, but all produce heavily and and easily with a small initial investment. Reuse pots from last years annuals, add a layer of compost and some fertilizer, and plant on plant per pot. Each year, add a pot, or make a "raised" bed.
[An] example of a vegetable that could yield big savings is tomatoes, says Greenberg. “Tomatoes can cost $2 to $5 per pound,” he says.
“A seed packet costs about $3 and can easily produce a harvest of 25 to 50 pounds.” - The Allstate Blog
Okra is just a hibiscus. Ornamental peppers are just chili peppers. Thyme makes the best ground cover. Blueberries have amazing fall color. Parsley adds great texture to mixed pots. I'm not even going to mention swiss chard! The list goes on! Adding fruits and vegetables to your existing gardens saves labor and looks great!
Gardening is an easy way to get anybody outside! Having children help plant edible plants can help improve self confidence, it's great exercise, and children are more likely to eat something they grew themselves! It also helps solidify math and science skills being taught in school.
Butterfield, Bruce. ''Impact of Home and Community Gardening In America.'' The National Gardening Association (2009): 1-17. Accessed April 2009. http://www.gardenresearch.com.