Mulch is a general term used for any material that allows air and water access to the soil while attractively covering the soil surface for a long time. Mulching garden beds is entirely worth the time and effort upfront because the benefits are more than just its attractive appearance. Mulching a garden pays off throughout the season and even in future years.
What is Mulch Used For?
Water Less Often
Mulch retains moisture in the soil; consequently the plant will require less frequent watering. Adding a top layer of mulch slows the evaporation of water from the soil, keeping moisture available for plants over a longer time period. Over time compost breaks down and contributes organic matter to the soil that also improves its overall ability to retain moisture.
Spend Less Time Weeding
Another time-saving benefit of mulch is its ability to slow weeds growth, so less time is spent weeding when a garden is mulched. The weed seeds below the mulch are inhibited by the lack of sunlight. Any weeds that do grow are more easily pulled from damp mulch than soil.
Pro Tip: Space plants slightly closer together than recommended to reduce time spent weeding.
Mulch Improves Soil Quality
Mulches of leaves, bark, grass, wood, and other plant-based materials have the added benefit of improving the soil fertility over time. The decomposing mulch turns into nutrient rich, loose soil with improved water holding and air flow. Improving water holding and air flow are key components to combat dense, compacted soil and grow healthy plants.
Mulching Minimizes Soil Temperature Fluctuation
Plants are affected by extreme temperatures of hot and cold. Providing a mulch layer insulates delicate surface roots from the harsh midday sun and damage from frost. Moderating soil temperature with mulch reduces damage to plant roots, which results in them being healthier and stronger.
When is the best time to mulch?
Mulch early! Spreading a layer of mulch is easier and takes less time if applied before the growth on perennials is in full swing and before annuals are planted. Aim to spread mulch as soon as the soil begins to warm in spring. For annuals, you can plant through the layer of mulch, rather than painstakingly spreading around each plant afterward. Add a 3″ layer of mulch around your plants.
Pro Tip: Leave a few inches of space around trunks and plants with woody stems. Mulch against the stem creates too wet of conditions and it may rot.
How Much Mulch Do You Need?
To determine how many cubic feet of mulch you will need to cover an area you’ll first need to calculate the square footage of the area using the following calculation:
Width in feet x length in feet = square footage
Next, using the square footage number, multiply it by the depth of mulch you will require, then divide that number by twelve to get the cubic feet of mulch needed to cover your space.
Square footage x depth of mulch (3 inches for example) / 12 inches = the total cubic feet of mulch needed
Using Ground Cover Instead of Mulch
Ground covers are a great alternative to mulching if your goal is to provide coverage around trees, shrubs, or open areas. The dense foliage of a ground cover helps reduce weeds, shade and cool the root zones of larger plants, and many ground cover plants produce small blooms to add a touch of seasonal color. Learn more about variety selection and planting ground covers in our article, How to Plant Ground Cover Plants.