Any organic (biodegradable) mulch material should be fine...straw, leaf litter, pine needles, shredded or chunky bark, or arborist wood chips. As it composts in-place, soil life will move that organic matter into the soil layers, supporting soil health and maintaining good conditions for root growth.

Our web page Soil Testing and Soil Testing Labs has information on the testing process and provides a short list of area labs to consider using. It can't screen for pathogens, pests, or similarly direct causes of damage, but will reveal any key nutrient deficiencies or if the soil acidity (pH) is outside of the ideal range for certain plants. Vegetable health and yield issues typically stem from other problems, like vulnerability to disease (some varieties can be more resistant than others), soil moisture irregularities, heat stress, a shortage of pollinators, and other environmental factors. You can also explore our vegetable resource pages for care and troubleshooting information in case they address the particular symptoms you noticed in certain crops.

Miri