How and Why You Should Lay Mulch: what you need to know

Most people would think I am crazy because I get so excited to apply mulch in my yard every year.  Have you ever noticed how a layer of dark mulch makes the landscape colors pop and look finished? There is more to this important landscaping element that meets the eye.

Mulching takes time and lots of hard work (it’s a great workout!) for large areas of cubic feet, but it is so worth it. I call mulch the top dressing or the frosting on the cake. It’s one of the last things you do to prepare your garden for summer. Mulch adds that protective layer your plants need to thrive.

What Is Mulch?

Mulch is any material that is spread or laid over the surface of the soil as a covering. It’s great for vegetable gardens, flower beds or any planting areas.

While all compost by definition consists of organic material, not all mulch is organic. The most popular form of mulch, sold in bulk or bags at garden centers, are wood chips or shavings, hardwood, and softwood bark. Other mulches are pine needles, pine cones, hay, straw, cocoa, rice, buckwheat hulls, other crop residues, tree leaves, and grass clippings.

Is mulch and compost the same thing?

Mulch and compost are not the same thing. Think of it this way, mulch is used on the top layer of the soil to control weeds, retain moisture and regulate temperature, whereas compost is used beneath the top layer of the soil where it provides essential nutrients.

Unlike mulching, which happens above the soil, composting happens below. So you can mix it into your topdressing or directly into the soil. It doesn’t matter just as long as the goods can get down to the roots of your plants.

The Benefits Of Mulching:

• Suppresses weeds – Mulch is the ideal natural weed controller! It helps prevents weed from sprouting and taking over the landscape by blocking their growth and access to sunlight.
• Improve water retention and soil moisture
• Improves the soil– Microbes and insects in the soil naturally consume the mulch over time, adding the by-products back to the soil in the form of organic matter..
•  Aesthetics- Adds curb appeal. Mulch instantly adds rich color and a manicured look to your landscape beds, along the foundation of your home, around trees and shrubs, and between garden beds
• Regulates the soil temperature– Mulch acts as an insulator, helping to regulate soil temperature to keep plant roots cool in the summer and warm in the winter.
• Prevents erosion

When to Use Compost vs. Mulch

Many people are confused when to use mulch and when to compost. The answer is, it depends on your goal. I apply compost in early spring to help the plant roots grow. Compost feeds the root systems and helps the soil structure. The right mulch offers moisture retention even if you only apply a thin layer to the top of the soil.

If you primarily want to enrich the soil to add nutrients and enhance its texture, you should work mature compost into the top few inches of your garden soil. If your primary concern is to keep the weeds at bay and use less water this summer, apply mulch, preferably one that decomposes over time so you get the added benefit of improving your soil.

Ideally, you do both—recycle as much of your yard waste and kitchen scraps as compost and mulch your garden beds.

Commercially available landscaping mulches include organic products like wood chips, shredded bark, and pecan shells, as well as non-organic products like gravel or landscaping fabric.

Types of Organic Mulch:

• Bark, Shredded or Chipped (wood mulch)
• Pine Needles
• Grass Clippings
• Newspaper
• Shredded Leaves
• Straw
• Oyster Shells (learn more about how to oyster shells in your garden)

Organic mulch will decompose and have to be replaced, but, it will also improve your soil’s structure and its organic content. The dryer and woodier the mulch, the slower it will decompose and the fewer nutrients it will give to the soil. I always recommend the very fine organic mulch that has been cooked so there is no weeds or weed seeds.

Mulching with oyster shells adds calcium to the soil and makes it more alkaline. Oyster shells in the garden eventually break down, but if you want to use them as ground cover under plants that need acidic soil.

Inorganic Mulch

Inorganic mulches comprise synthetic materials – plastics, landscape fabrics (geotextiles), stones, and rocks. They are used because the materials don’t decompose, or only break down after extended periods of time. Thus replacement costs are diminished.

There are two primary types of plastic mulching: black polyethylene film and clear polyethylene. The black plastic film ihelps for eradicating weeds, warming up the soil during the cold season, as well as retaining the soil’s moisture.

On the other hand, the clear plastic film works best for warming up the soil and promoting faster growth early in the growing season. Clear plastic film, however, isn’t as efficient when it comes to suppressing weed growth.

The dark rich mulch is what I use in my garden. The darker the better. I am not a fan of bark mulches because they don’t break down as fast and don’t contain the variety of organic matter that nourishes the soil. The dark mulch is not only good for your plants it looks so nice next to my flagstone pathway. It’s so clean!

Synthetic, man-made mulches are rubber, plastic sheeting, or geotextiles such as landscape fabric, cardboard, and newspaper. Only the last two decompose, whereas plastic breaks down into smaller pieces over a long period, and eventually end up contaminating the environment as microplastics. I always use the natural sustainable mulch to to as eco-friendly as possible. 

The third group of mulches are materials that are also not degradable, but they are natural: crushed seashells, gravel, pebbles, stone chips, and slate.

When to mulch?

Mid- to late spring is mulching season-that’s when the soil is warming up from the freezing temperatures it experienced all winter. Doing it too early will slow down the warming process, which the soil needs to do its job.

If the winter is extremely cold, add mulch in fall or winter to insulate the roots of the plants. This will prevent freezing that can damage your plants before the new season as the mulch creates a warm cozy blanket. It will also reduce the erosion of soil that happens because of the rain.

How to Mulch?

1. Clean out your beds — Remove dried up leaves, debris, sticks, and old mulch from previous years. You should also take the time to freshen up the edging along your beds.
2. Water your beds — If your area has experienced none recent rain, you should wet down dry beds. As mentioned above, the mulch helps to seal in the moisture.
3. Remove weeds — A major benefit of mulching is that it suppresses weed growth, so cleaning out weeds gives you a head start.
4. Spread mulch — Shovel mulch from your wheelbarrow or shake mulch from your bag into small piles. Then use your hands to spread the mulch, especially as you get close to the base of your plants. How much mulch should you apply? You should spread your mulch to be two to four inches thick. If your mulch is too thin, then weeds can push through. If your mulch is too thick, it prevents water from reaching the soil.
5. Water after mulching — This is an optional step, but a final watering can help settle the mulch into place.

DON’T volcano mulch around trunks of trees!

What is Volcano Mulching?

Volcano mulching—when mulch is piled high, tight, and thick around the base of trees. The mulch should not touch the tree trunks. Volcano refers to when the mulch is the shape of a volcano—is a common but unfortunately destructive practice that prevents water and oxygen from reaching the roots.

What’s more, as hardwood mulch begins to breakdown and decompose, the temperature in the mulch rises, subjecting the tree trunk to damaging temperatures. No mulch volcanoes.

How much mulch do I need?

First, determine the square footage of the area you want to mulch by measuring it. Multiply the length and width of the area to cover and record the answer.

Determine how deep mulch should be by going with gardening experts’ recommendation of a 2- to 4-inch layer.

Multiply the square footage of your area to be mulched by the number of inches of mulch you want to apply. Then divide that number by 12, as a cubic foot of mulch will cover 12-square feet with about 1-inch of mulch.

Read more about the best indoor plants that require little work.

Read more about garden design and my favorite garden plants. Like the teddy bear rhododendron,

Most Frequently Asked Questions about Mulch

Q: What types of materials can be used as mulch? A: Common types of mulch include organic materials like bark, wood chips, straw, and compost, as well as inorganic materials such as gravel or plastic sheeting.

Q: How thick should mulch be applied? A: Generally, mulch should be applied at a thickness of 2 to 4 inches. However, the ideal thickness may vary depending on the type of mulch and specific gardening needs.

Q: When is the best time to apply mulch? A: Mulch can be applied at any time of the year, but it is often best to apply it in the spring or early summer to help conserve moisture and suppress weeds during the growing season.

Q: How often should mulch be replenished? A: Mulch should be replenished as needed, typically once or twice a year. Factors such as weather, decomposition, and compaction can affect the longevity of mulch.

Q: Can mulch attract pests or diseases? A: Properly applied mulch is unlikely to attract pests or diseases. In fact, it can serve as a barrier that helps prevent certain pests from reaching plants.

Q: Is it necessary to remove old mulch before applying new layers? A: It’s generally recommended to break up and fluff old mulch before applying new layers. However, complete removal may not be necessary unless the mulch layer becomes too thick.

Q: Can any mulch be used for vegetable gardens? A: Yes, organic mulches like straw, compost, or shredded leaves are often recommended for vegetable gardens. They help retain moisture, suppress weeds, and contribute to soil health.

Q: Can mulch contribute to overwatering? A: While mulch helps retain soil moisture, it doesn’t directly cause overwatering. Proper watering practices should still be followed to maintain the right balance of moisture for plant health.