Think in functions
A raised bed needs water-holding capacity, air space and stable organic matter. Local materials vary, so judge texture and drainage rather than copying a rigid recipe.
Test before adding more
When possible, use a soil test before applying concentrated fertilizer, lime or micronutrients. Excesses can be harder to correct than deficiencies.
SEEDSUN guides are general educational information. Climate, cultivar, soil, label directions and local regulations can change the right answer for a specific garden.