Mulch: A Gardener’s Best Friend

If I can convince you to try out one new gardening practice this growing season, let it be mulching.

Mulch is the unsung hero of the landscaping world. It helps conserve water, protects your plants, fights weeds, manages soil temperatures, and so much more!

What is mulch?

Mulch describes a variety of materials that are added to the soil’s surface, usually for the purpose of protecting plants or soil, reducing weeds, or adding some aesthetic flair to your landscaping.

Types of mulch

You can mulch your garden beds or landscaping with a variety of materials.

Organic (that is, biodegradable) mulches – like wood chips, straw, and grass clippings – have the benefit of adding nutrients to your landscape as the materials break down. Most are pretty inexpensive (even free, if you mulch with your own grass clippings or use arborist wood chips).

Inorganic mulches – like rock, pea gravel, or landscaping fabric – tend to stay in place better and don’t need to be refreshed as often. However, they're not right for all types of plants or yard spaces and lack many of the benefits of organic mulch.

Benefits of mulching

• Helps you water more efficiently by retaining moisture for your plants and reducing how much water is lost through surface evaporation (bonus: mulch often makes it so you can water less frequently!)
• Makes it harder for weeds to grow, decreasing your weeding time!
• Improves soil nutrition and tilth ("tilth" refers to the physical properties of the soil which make it easier for seeds to emerge and for plants' roots to grow deeper)
• Prevents soil compaction
• Stabilizes soil moisture and soil temperature extremes
• Can give your yard a clean, finished look
• Encourages soil microorganism activity (which is great for plant health!)

Using mulch in your yard

Where to use mulch

You can add mulch:

• To garden beds: organic mulches protect the soil and plants from surface evaporation, temperature extremes, and weeds; they also add nutrients to the soil as they break down
• To areas around trees and shrubs: organic mulches give a finished look to landscape features like trees and shrubs, all while preventing soil compaction and protecting the soil and plants from surface evaporation
• To areas with heat-loving plants (like cacti and succulents): inorganic mulches like rock and pea gravel can serve as a “heat sink”, as they hold in heat

How to apply mulch

How much mulch you should apply depends on what type of mulch you use and where.

If you’re purchasing your mulch materials, always reference the packaging for specific instructions.

If you’re adding organic materials like grass clippings, straw, or wood chips, a good general guideline is to not exceed 1-2 inches of mulch. Larger mulch chips can be applied at up to 4 inches deep. Anything thicker than 4 inches could smother the soil and reduce the amount of oxygen available to your plants (something you want to avoid at all costs).

Things to avoid with mulch

• DON'T use lightweight organic mulches (like straw and small wood chips) in extremely windy areas, as it will not stay put
• DON'T apply mulch of any kind on top of a lawn you want to keep! This will smother and kill the grass
• DON'T use hay in place of straw, as hay usually contains seeds that will germinate and cause weeding issues in your garden. Instead, buy seed-free straw (or make sure your weeding tools are handy!)
• DON'T apply mulch to any areas where you’re trying to grow new plants from seed