As a colored mulch producer, TLB Wood Products LLC, has been educating landscape contractors on the harm rain can initially do to colored dyed mulch. When mulch is dyed, a color based dye is used and until the colorant dries on the wood it is at risk to lose its color properties. When the colored material is in a pile the inside can't fully dry and lock into place. Even if the material sits for a week the dye may not have officially locked. We recommend 6+ hours of sun and wind to allow the colorant to dry and lock into the wood mulch. It will take longer for mulch to dry on an overcast day that is muggy and not windy. So, if you are laying color dyed mulch be ware of rain that is in the forecast.
If you happen to have mulch in a pile that has been rained on before it has had a chance to lock you may not be in too much trouble. The inside of your pile will still be wet with colorant and once there is no rain in the forecast you can turn the pile into itself as only the outside of the pile should be the only place where the wood has lost color. We do not recommend turning the pile until you are ready to use the mulch AND there is no rain in the forecast.
If you have already laid the mulch than you may have lost some or all color properties. If there is still some color left, you can try to rake up the mulch and turn it however most likely the colorant has washed into the soil.
Spread the word to minimize loss!
