Benefits of Mulching
Long before modern day use as a purely decorative element, mulch had an established history of benefitting plants, soil and gardeners. This is still its highest calling. A good layer of beneficial mulch can reduce stress on plants by regulating soil temperatures and reducing moisture loss and competition from weeds. In the veggie garden it also helps keep leafy veggies from getting splashed with dirt each time it rains. Beneficial mulches do their final good deed when they break-down and enrich the soil as they age. All of these benefits mean the gardener gets healthy soil and plants with less time spent on watering, weeding, fertilizing…and washing grit out of salad greens! Not applying chemical fertilizers and reducing watering also means fewer chemicals in the environment and more green in the wallet.
Which Mulch Where
For Landscape Beds: cocoa hulls (not around dogs!); shredded leaves; dry grass clippings (fresh, green ones will get matted and stinky); pine needles; nut shells; rich, dark compost
In Vegetable Garden: straw; shredded leaves; dry grass clippings; more rich, dark compost. For walkways & weed suppression in unplanted sections - not around plants - newspaper or cardboard (which can be composted at season's end)
Around Trees: A layer of mulch may help very young trees retain moisture in their small root zone, but established trees really do not need to be mulched. If you desire a distance around them to keep the mower or trimmer away, living groundcover is better. If you do go with mulch, select from those listed above and keep it away from trunk!
Save it for Pathways: sawdust, bark chips and shredded wood are not among the “beneficial mulches" as they use too much Nitrogen and tie up soil microorganisms in their breakdown - depriving plants, and they can become solid mats that block water penetration. Wood products can also harbor molds, plant diseases and chemical contaminants.
When & How to Apply Mulch
Mulch can be added at any time, but autumn or spring are most typical. An autumn application in the veggie patch will help with soil enrichment for spring seedlings. Perennials that have borderline hardiness in your area can also benefit from the insulating effects of a heavier mulch layer atop their roots in late autumn. In all areas, spring applications will best help with moisture retention and weed control, while also enriching soil. An additional midsummer application, to still producing vegetable plants, is a good idea if earlier applications are well-deteriorated.
Beneficial mulches can be applied around existing plants or placed ahead of time and planted through. A two inch layer is sufficient around plants; thicker layers can be used in unplanted areas. Water the soil well before placing the mulch and do not mulch up against stems and trunks, to avoid rot issues. A wheelbarrow and a shovel, or garden fork, are often the most helpful tools for getting the mulch to where it is needed, especially for large areas. A bucket can also be very handy for sprinkling mulch around plants and a hand-size garden fork for spreading in tight quarters.