When it comes to the soil in your garden, the important factors are texture and pH level.
The ideal garden soil has a slightly crumbly texture that sticks together when pressed into a ball, but falls apart again if poked. There is a wide variety of natural textures with different characteristics.
Clay is heavy, retains a lot of water and is loaded with nutrients. That is good for greedy plants, but the downside is that it turns rock-hard when dry and is easily compacted when too wet. Sandy soil drains well, but does not retain a lot of nutrients either. To improve the texture of any soil type, mulch with plenty of organic compost and work it in after the season.
The pH level is the other important property. Most fruits and vegetables prefer a neutral to slightly acidic soil, at around pH 6 – 7. To test your soil at home, you can buy a pH Test kit and do a pretty accurate test yourself.
To improve acidic soil, work in lime to raise the pH level. However, it is very hard to lower the pH of soil that is too alkaline – a solution to this could be raised beds filled with compost instead of growing your vegetables straight in the ground.
You can get testing kits in any garden store or from online retailers.