This looks like a good idea!!
Raised beds eliminate root rot
Raspberry plants hate wet feet, and they are gross feeders. We addressed these two critical points by building a 20-inch-high raised bed and filling it with a mixture of four-fifths good garden topsoil blended with about one-fifth sand, peat, and well-rotted manure. If, like us, you have acidic soil, you will also need to add some lime, because raspberries prefer a soil pH of around 6.0. We left one end of the box open to allow easy access with our wheelbarrows, then closed it in when the box was full. This job can be done in the fall, so you are ready to plant, come spring.
If you have rich, deep soil that drains well year-round, you can simply plant your raspberries in a permanent garden site. Not us. The Pacific Northwest gets rain all winter, and many gardeners lose raspberries to root rot because they make the mistake of planting their raspberries' fussy little toes directly in the ground, which is often soggy clay covered with a skim of topsoil. We also experience a two-month drought most summers. Raised beds allow us to have deep soil that holds moisture evenly yet drains well.
It is important that you do not establish your raspberry patch in an area where you have recently grown tomatoes, peppers, or potatoes, to avoid verticillium wilt, which these vegetables can carry, and raspberries can catch.
