Raised bed soil mix is sold at most big box stores and it should be ready to use straight out of the bag to fill your beds. The most important consideration for a raised bed soil is drainage which is most often solved through the addition of perlite, this allows water to not stagnate around the roots and ensures the bed can drain if overwatered.
- Avoid products labeled garden soil as those are often designed for in-ground gardening and contain little to no drainage aiding ingredients which could lead to plants drowning.
- Keep in mind that even though bagged mixes may have some small amount of fertility adding additional fertilizer, compost, manure, or some mineral-based add-ins will ensure your garden thrives.
For a more complete in-depth guide to soil mixes and amendments check out the following article: Organic Raised Bed Soil
Here's a list of all of the Birdies beds we sell, their configurations, and the required amount of soil you'll need for each: Filling beds by size
Here is a quick video https://www.youtube.com/watch?v=JiJFORpbYgE
Make sure to check out the video on that page for some tips on saving $ filling your beds up!
Hope this helps! Please let me know if you have any questions or if I can be of further assistance,
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