Answer: The very best thing to add is compost. Composted organic matter helps the soil hold water and nutrients better while maintaining good drainage. It also provides a natural source of nutrients as it continues to break down over time.
You can make your own compost from leaves, grass clipping and other yard wastes. However, for a quick start, you may need to purchase some. Check with local nurseries and soil yards to see what types of compost are available in your area. You can usually find it by the bag, which is more expensive but easier to handle for small raised bed area, or by the cubic yard, which is less expensive and may be delivered to your home.
If you can mix compost 30 to 50% with your native soil, that should be a good mix for the garden. So, adding 3 inches of compost to the surface and mixing it into the top 3 to 6 inches of soil would be great.
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