In the summer months, it's more important than ever to mulch your garden beds. Not only does mulch conserve moisture in the soil by slowing down evaporation, it also suppresses weeds and improves soil fertility and texture. This means you are saving water, cooling the earth, and keeping the soil healthy -- all while making your garden beds look nice and neat at the same time.
For an edible garden, organic mulch is the most common type used. It includes (formerly) living organic material such as compost, straw, grass clippings, dried leaves, pine needles, shredded bark, and wood chips. Organic mulch is spread several inches thick over the whole garden bed, around the base of your plants, at the beginning of the season. Over the course of a few months, it decomposes naturally and creates rich organic matter for your soil.
Generally, woodier mulch (like bark) takes a longer time to decompose and will last a whole season. Very fine mulch (like compost) breaks down quicker and may need to be reapplied mid-season. Though the woodier mulch may seem to make more sense, keep in mind that it won't add as many nutrients to the soil each season.
The easiest and cheapest mulch to come by is what you already have in your yard: grass clippings from the mower, or dried leaves or pine needles from your trees. Rather than filling up the city's green waste bin with your clippings and leaves, redirect that mulch to your garden. (And if you have neither, it wouldn't hurt to ask a neighbor if you can take their leaf piles off their hands!)
If you have a compost heap in your backyard, the resulting "black gold" that you'll get is the perfect organic mulch: full of worms and rich in beneficial microbes. Every time you water your garden, you're feeding the soil with all that composted goodness.
Another way to get organic mulch on the cheap is by calling a private tree trimming company or public utility company, and asking if they will deliver a truckload of wood chips to your house. Often times, these companies will bring you several cubic yards of chips from their last tree trimming job for free (or for a modest fee). For them, it's an environmentally friendly way to dispose of green waste and for you, it's an excellent way to obtain quality mulch in bulk.
If you live near a feed or livestock supply store, you can buy a bale of straw to use as mulch. Make sure you are getting straw, not hay; hay contains stalks with the seed heads intact, and you definitely don't want to spread anything in your garden that will sprout.
If you're particular about the aesthetics of your garden beds, you can purchase bagged shredded bark from most nurseries and garden centers. This type of mulch comes in a variety of tree barks (cedar, pine, spruce, redwood, and more) that is uniformly shredded and works well for people who only need a bag or two at a time.
Another type of bark mulch is not bark at all, but wood (usually recycled construction materials like pallets, 2x4s, etc.) that is shredded to look like bark. An advantage to this mulch is that it's often dyed black, brown, or red to blend in with various landscapes. While attractive, a disadvantage is that artificially colored mulch is not the most eco-friendly pick as the dye will leach into the soil over time.
If you have some shovels and buckets and are not afraid of a little sweat, the best source of mulch -- that also happens to be free --is the City of Los Angeles Bureau of Sanitation. This is where all your yard waste from the green bins go; the Bureau of Sanitation collects it, screens it, grinds it, and turns it into piles of aerated mulch in their "Closing The Loop" service.
The mulch giveaway program is a city-wide program open to all L.A. residents (and whoever is willing to make the trek to the program's 11 locations). The locations span across the county from West L.A. to East L.A., and from Lake View Terrace to San Pedro. Each location has separate operating hours and mulch drop-off schedules. Some locations clear out quickly, so it's best to arrive on the day of, or day after, the mulch is delivered to them. Click here for a map of all locations.