The native soils that we have in the Puget Sound area are good for growing palms.  There are however, a few things to keep in mind.

Palms do not like to sit in water.  Keeping this in mind when planting a palm tree, put 4 to 6 inches of coarse sand or pea gravel in the planting hole first and keep the base of the palm 4 to 6 inches above the grade.

If you run into clay or hardpan, stop digging and plant on top of this surface.  Add the drainage material and the palm.  You can mound the palm as high as needed and it will do well.  We have a couple of 20 foot palms at the farm that are planted on top of the soil surface and are mounded to a 6 foot diameter.  They have been doing well for ten years.

If you are building a new planting area and need to bring in soil, use a 3 or 4 way soil with 25% to 40% sand. You are looking for soil that drains well.  

Do not use Miracle Grow or Miracle Grow soil with palms!

SOIL CONDITIONS