Organic mulch is an invaluable fertilizer for your garden. It enriches your soil and improves its texture and quality. Any kind of plant can benefit from a good mixing of mulch in its soil. Mulch provides protection from erosive elements and it helps to hold moisture in your soil; it can also reduce the amount of weeds you have growing in your garden.
Mulch materials can be found in your own yard. Bark and wood chip mulches make a neat finish to the garden bed and will eventually improve the condition of the soil. Leaves are another readily available material for mulch. Compost makes great mulch; it not only improves the soil structure but also provides an excellent source of plant nutrients. Depending on where you live, numerous other materials make excellent mulches. Straw, seaweed, ground corncobs, lawn clippings, newspaper and pine needles also make good mulch material. Avoid crabgrass and grass full of seed heads. Pine needles tend to increase the acidity of the soil, so they work best around acid-loving plants. Also, do not use clippings from lawns that have been treated with herbicides or a fertilizer/herbicide combination.
For best results, remove any existing weeds before applying mulch. For trees and shrubs, spread mulch evenly to a depth of 2 to 3 inches. For trees and shrubs in beds, mulch the entire bed. For those in a lawn, mulch a wide ring beginning 3 to 6 feet from the trunk and extending to the drip line. Never pile mulch against tree trunks. As organic mulches decompose, they may need to be replenished somewhat every year. However, don’t let mulch build up to depths greater than about 4 inches; the deep mulch can suffocate the roots by stopping free air exchange and in some cases causing soil compaction, which blocks the penetration of water and fertilizers into the soil.
Mulching Vegetables
Vegetables, which are grown from transplants, should be mulched sparingly (about one inch deep) when they are young, gradually increasing the depth of the mulch to three inches, as the plants grow taller. For low growing plants, such as lettuce and radishes, the mulch should be applied on either side of the row, but at a depth of only 1½ to 2 inches instead of the usual 3 inches. For vine plants, such as cucumbers and melons, the entire area over which the vine will grow can either be mulched with fine mulch that doesn’t provide cover for bugs or the area can be left weed and mulch-free.
When Should Mulch Be Applied?
When you apply mulch depends on what you hope to achieve by mulching. Mulches can moderate the soil temperature by providing an insulating barrier between the soil and the air. This means that a mulched soil in the summer will be cooler and may not freeze as deeply in the winter. However, since mulch acts as an insulating layer, mulched soil tends to warm up slowly in the spring and cool down slowly in the fall when compared to bare soil.
Summer mulches are normally applied in mid-spring. For best weed suppression, apply mulch in early spring. If you are using mulch in your vegetable or flower garden, it is best to apply it after the soil has warmed up in the spring. If you are adding additional layers of mulch to existing perennial beds, wait until the soil has warmed completely.
Mulches used to protect plants over winter should be loose material such as straw, hay, or pine boughs, which will help insulate the plants and still allow moisture and air to penetrate the soil.
What Kind of Mulch Should I Use?
Mulch Material
Depth
Notes
Bark Chips
2 - 4 in
Recommended for mulching around landscapes such as trees shurbs and perennial beds.
Wood Chips
2 - 4 in
Same uses as bark chips. If fresh wood chips are mixed with a lot of chopped leaves, composting is recommended.
Leaves
3 - 4 in
Best if chopped and composted. Decompose fairly quickly and improve the soil once decomposed.
Compost
2 - 4 in
Excellent enriching material for incorporating into the soil.
Lawn Clippings
2 - 3 in
Layer gradually, using dry grass. A thick layer of green grass gives off excessive heat and foul odors rather than decomposing.
Newspaper
3 - 4 sheets
Apply newspaper and cover with a thin layer of another mulching material, or cover edges with soil.
Straw
6 - 8 in
Recommended for vegetable and fruit plantings. Excellent insulation for winter mulching. Avoid hay with seeds.
Pine Needles
4 - 6 in
A good choice to use around acid-loving shrubs, trees. Long-lasting.
Decorative Bark
1 - 2 in
Attractive, functional and long-lasting. Best used over landscape fabric for weed control.
How Much to Apply
The amount of mulch to apply will be determined by the material you are using and the area to be mulched. Determine the area in square feet then use the table to help you figure out how much mulch you will need. Mulch is measured in cubic feet (ft3) or cubic yards (yd3). As an example, if you have an area 10 feet by 10 feet and you wish to apply 3 inches of mulch, you would need 25 cubic feet or about 1 cubic yard.
Or use these formulas:
ft2 to be covered X inches of mulch = Cubic Feet of Mulch 12
ft2 to be covered X inches of mulch = Cubic Yards of Mulch 324
Area to Mulch in Square Feet
Desired Thickness
of Mulch in Inches
Volume of Mulch
Needed
25 sq ft
2 in
4 cu ft
1/5 cu yd
3 in
6 cu ft
1/5 cu yd
4 in
8 cu ft
1/3 cu yd
100 sq ft
2 in
17 cu ft
2/3 cu yd
3 in
25 cu ft
1 cu yd
4 in
33 cu ft
1 cu yd
1,000 sq ft
2 in
170 cu ft
6 cu yd
3 in
250 cu ft
9 cu yd
4 in
330 cu ft
12 cu yd
How to Make A Compost Pile
The first step to making your own compost is to rope off an area in the back of the yard or off to the side where it will be out of the way but easily accessible. In order to start a compost pile, you will need to find a patch of ground that doesn’t have anything important growing on it, as the compost pile will quickly obliterate any grass or plants it sits on. A good time to get your compost pile started is in the fall when the leaves are falling. If you rake all of your leaves up and place them on the compost pile, you will have a great start to some rich, dark compost. Occasionally, you will want to turn over the contents of the pile with a shovel to encourage even decomposition of the compost products. You can also add grass clippings, weeds, twigs, pine needles, fruit and vegetable peelings, newspapers, and any other organic material that comes into your possession.
For additional information on mulch and composting visit: San Luis Obispo Integrated Waste Management Composting
