It's a good question. The alternative is to put the garden in the ground which people have done for centuries with success. Why change a good thing? For the small home garden raised beds are a much better option. Below you will find several advantages for using raised beds.
Here are 8 reasons why you should consider gardening in raised beds:
1. You control the soil. You get to start off with a great soil mix from the beginning. Often the ground in our yards and gardens is less than ideal for planting vegetables. Building a raised bed lets you control that factor.
2. Added height can be important to many gardeners for several reasons. The plants are closer to you which means they are easier to plant, maintain, and most importantly harvest! Older gardeners who may not be able to bend very well and handicapped gardeners can still garden with raised beds because of the extra height.
3. You avoid soil compaction. The more you walk on the dirt the more compacted it becomes. Gardens in raised beds are not usually walked on and they do not become compacted. This allows the roots to get the oxygen and moisture they need.
4. You can plant more plants in a smaller space! Because your soil is better than the average soil you have a higher nutrient content in the soil. You can put more plants closer together and the plants will have all the nutrients they need to thrive. This results in more veggies for your dining enjoyment.
5. There are very few weeds in a raised bed garden. At least this is true initially, later the weeds may come but they are easier to remove since the soil is in such great shape!
6. Your growing season is longer because the raised beds warm up faster.
7. They have better drainage than most other soils. Better drainage could be a slight disadvantage since you will have to water more frequently during dry spells.
8. Probably the best reason for a raised bed is if you have a troublesome site where you can't dig. Many areas of Tennessee are almost solid rock so you can see where a raised bed might come in handy. If you can't dig down build up! Raised beds are your best bet for a plentiful crop of vegetables.
If you are looking for some things to think about when you're designing your raised bed garden look here!