The benefits of mulch aren’t limited to blocking weeds and retaining heat and moisture.
A 2011 report (1) from Texas A&M University report mulching a vegetable garden can allow one to grow 50% more vegetables. The rows can be spaced closer together and there is little need to cultivate the soil.
Potatoes can grow in the mulch as well as under it. They will also be easier to harvest and have less of a chance of bruising when uprooted.
The same report said that mulching will also increase fruit yields by discouraging fruit rot. Tomato plants are more likely to rot when they touch the soil and the mulch prevents soil from splashing onto fruits, keeping them cleaner.
One of the most important properties of wood and bark mulch is it takes several years to decompose, which is a double-edged sword. It’s a blessing because mulch can be placed between garden beds and on walking paths and will not need to be replaced for years, but when used in a garden bed it will not break down at the end of the season and tie up some of the nitrogen that plants need.
For that reason, gardeners have phenomenal success when they incorporate nitrogen-rich products like blood meal with their bark mulch inside a garden bed.