Fall is the best time to get that organic matter, added into your raised bed soil so that it will break down over the winter and be available for your plants in the spring. We don’t add fertilizer because the fertilizer will get leaked out of the soil by rain and snow all winter. We had our fertilizer in the spring. In my 2’ x 8’ x 2’ beds I add every year 1.5 ft.³ of organic raised bed, soil and one cubic foot of organic compost. I manually turned the soil over and mix those amendments in with