This article is a guide to using mulch in your garden. Mulch is a layer of material, either organic or inorganic, that sits on top of the soil as a layer of protection. There are many benefits to adding a layer of mulch:
1) It will hold moisture in the soil- even a thin layer will cut evaporation in half.
2) It will moderate root temperature, keeping the plant warmer in the winter and cooler in the summer.
3) If organic mulch is used, it will slowly decompose and improve the quality of the soil.
4) If your layer of mulch is thick enough, it will discourage the growth of weeds (they won’t receive the sunlight they need, and any seeds that land on your garden won’t be able to take hold).
5) It will give your garden a pleasant, uniform look, and give you some options in the brightness and color you wish to have.
The first four will improve the health and strength of the plants in your garden. The last will help with its aesthetics.
WHAT TO USE FOR YOUR MULCH?
You can use many different kinds of materials for your mulch. Inorganic material (stones, rocks, etc) will give you the benefits of retaining moisture, moderating temperature and discouraging weeds.
Using organic material will give you the extra benefit of improving the quality of your soil. Adding organic material to your soil is the single best way to improve it, by adding nutrients, improving the movement of air and water through the soil, and encouraging helpful organisms to stick around. (To learn about this in much greater detail, check out the benefits of composting).
Some common organic materials used for mulch:
Shredded or Chipped Bark: this will break down slower than other organic materials. It adds a nice, rustic feeling to your garden. Cyprus will generally last the longest.
Straw: Very functional, but doesn’t look too pretty. Straw is great for vegetable gardens.
Grass Clippings or Chopped Leaves: both of these will break down quickly, and add lots of nutrients to your soil. They work well in vegetable gardens or perennial beds, and can be placed under better looking mulch. Keep in mind that since they break down quickly, this can actually heat up the soil.
Compost: Looks natural, and will add tons of nutrients to your soil.
Pine Needles: Good if you’re looking to increase the acidity of the soil.
In functional gardens where you don’t care how things look, straw or grass/leaves plus some compost is ideal. For a natural look, go with compost or bark. For a brighter look, you can use bright gravel and a lighter bark color.
Fine textures will be more effective, so a thinner layer will be needed. Bigger chunks will leave things more airy.
Never use diseased plants in your mulch. Don’t use plants the spread easily, unless they’ve been completely dried out.
HOW MUCH MULCH TO USE?
To figure out how much mulch you’ll need for an area, here’s a quick guideline.
1) Measure the space of you’ll need to fill with mulch. If your garden is 10 feet by 5 feet, you will need to cover 50 square feet (10×5).
2) Divide by 12 to find how many cubic feet you’ll need.
50 / 12 = 4.2
3) Finally, multiply this number by how deep you want your mulch to be. If you want your mulch to be 3 inches deep, multiply by 3.
4) 4.2 x 3 = 12.6
So, you would need 12.6 cubic feet of mulch to fill your garden.
To figure out cubic yards, divide this number by 27 (0.47 cubic yards will be needed, in this example).
APPLYING YOUR MULCH
1) Before applying the mulch, add some fertilizer to your garden.
2) If your mulch is in a large bag, lay the bag beside your garden. Slice from top to bottom, and turn the bag over, spilling its contents out. This method is a lot more back-friendly than the sprinkle-like-cereal method.
3) Use a rake to even the mulch out over the full area, creating a balanced, unified layer.
4) Keep some space between the mulch and your plants, about an inch is usually good. Getting too close can smother the plants, and make them more susceptible to pests and rot. This will create a “donut effect” with your mulch around your plants.
5) Keep your mulch between 2 and 3 inches deep. Any more is unnecessary, and less than two inches will let light in an allow weeds to germinate.
6) Remember that organic matter decomposes, so you’ll need to add a new inch of material every year.
SOME FINAL TIPS
If weeds are a big issue, put down a layer of newspaper before adding your mulch. This will help to really eliminate the sunlight, starving the weeds.
After planting new plants, add a mulch of straw or chopped leaves/grass clippings to keep water in and encourage root growth.
Mulching in the fall is a great idea- the constant thawing/unthawing of the soil during the winter (frost heaving) can damage the roots. A layer of mulch will help stabilize the temperature, keeping your roots safe.
Good luck and stay prepared!