March 9, 2016 by Jeff Lowen
Don’t put mulch down too early in the spring. Give the soil a chance to warm. Mulching too early will actually slow down the warming process. Normally, mid- to late spring is the best time to put down mulch.
When to Mulch
When the weather gets warm, we’re always in a hurry to get our landscape looking its best, so we pile on the mulch. Don’t put mulch down too early in the spring. Give the soil a chance to warm. Mulching too early will actually slow down the warming process. Normally, mid- to late spring is the best time to put down mulch.
Seedlings can work their way through a thin layer of mulch, but too deep a layer could be impenetrable. Let your plants get off to a good start first. You can always add more mulch after the plants are established.
You may need to apply additional mulch in the summer to retain moisture and in the winter to insulate from cold.
If your garden has a layer of winter mulch, pull it away gradually as the temperatures warm. If you remove it all at once, the tender, new growth underneath could be affected by a late-season cold snap.
How Much Mulch
One reason we apply mulch is to control and kill weeds. It can do the same to your desired plants, so don’t pile too much on them. Knowing how much mulch to use can be tricky. A 1- to 2-inch layer of fine mulch should be sufficient, while a coarser material should be 3 to 4 inches deep. Too much of either type can suffocate your plants. In areas where you simply want to keep anything from growing, you can lay it on as thick as you like.
Coverage will vary greatly based on what type of mulch you use and how deeply you layer it.
To prevent stems and bark from rotting, pull mulch away from woody stems and tree trunks 1 to 2 inches. Also, if mulch is touching the plants, pests — such as mice and slugs — can find a great hiding place and a free lunch. A pre-shaped mulch tree ring is an option to place around trunks.
Mulch that’s too deep will stimulate root growth in the mulch layer rather than in the ground. The resulting shallow root system is susceptible to cold and drought damage.
Where and How to Mulch
From an appearance perspective, consider the size and style of the area you’re putting the mulch in. For example, pine bark nuggets may be too large for a bed of annuals but perfect for an area around trees or shrubs.
Pathways, slopes and areas prone to flooding or high wind need special consideration. Consider using a heavier or larger material here. There are mulch products manufactured specifically not to float away.
The area needs to be weed-free before mulching. In general, the bigger the pieces or chunks, the deeper the layer needs to be. Smaller-sized mulches will work their way into the soil more quickly.
If you wish, you can work most organic mulches into the soil at season’s end to improve the soil.
There are several products to consider when mulching: Work gloves prevent wear on your hands. Since mulch is light compared to other materials — like soil — a larger-capacity wheelbarrow (8 to 10 cubic feet) saves time when transporting mulch to your garden or flower beds. A bow rake is great for spreading mulch evenly.
Insects and Mulch
During wet seasons, you may notice that there are more bugs than normal in your mulch, but these insects don’t tend to cause problems.
Termites might be attracted to the wood in compost, but they like larger pieces of wood. They don’t like finely shredded mulch or bark nuggets, and mulches made from cypress, cedar or eucalyptus are not as popular with the termite set.
Shredded rubber mulch or other inorganic mulches like stone or crushed rock are excellent alternatives if you find your mulch is popular with insects.