April is a good time to add mulch to any beds that are bare to the elements. The beneficial microbes underneath the soil will thank you for it by giving your plants a boost in appearance through robust, greener leaves and more flowers. Earthworm activity increases as mulch helps to keep the soil cool for them. Applying mulch in April helps prevent water from evaporating quickly from the soil in hot weather. The last thing anyone wants to see is a plant wilting in the sun after just watering it. We use only one kind of mulch; Mini Mulch Fir Bark. We buy ours from two places, depending on what city we are gardening in.
To find mulch in the San Jose Bay Area, see:
Lyngso Garden Materials
Read more about the attributes of mulch on the U.S.D.A.