How to Mulch Effectively
Written by: Dottie Baltz
Mulching may seem like a no-brainer for many of us, but I am still surprised at how many bad mulching jobs I see around town, especially ones done by so-called professional landscapers, so I thought it was my duty to write an article about it.
Why Mulch?
Mulching improves the appearance of gardens and landscapes, but more importantly, organic mulches will add nutrients to the soil and will also help condition the soil over time. Mulches also perform a huge service to us gardeners by preventing weed growth. The less time I spend weeding, the more time I can spending planting or just enjoying the garden.
Mulching also is important because it keeps the soil temperature at a more constant temperature. In summer, the soil is cooler, even during hot weather, which is better for plant growth. In winter the soil stays cold during warm spells and helps prevent heaving of some plants.
What to use as Mulch
I prefer organic mulches that break down over time. Yes, you have to reapply them every year or two, but they will improve the soil and attract beneficial insects and organisms to the soil.
I understand that there may be instances where an inorganic mulch will work better, such as in a cactus garden, or up against the house or in a pathway. But generally, if you can stick to an organic mulch, the plants will be happier for it and it will be easier to maintain.
Types of Organic Mulch
- Shredded Bark Mulch
- Shredded Wood Mulch - should be composted or aged for at least 6 months before using
- Grass Clippings
- Compost - Yes, well aged compost can act as a mulch
- Coconut Bark
- Cocoa Bean Hulls
- Pine Needles
Types of Inorganic Mulches
- Rocks
- Pea Gravel
- Recycled Tires
- Weed Block Fabric - I tend to avoid unless it is for use under rocks or decks
- Plastic Sheeting - I use this temporarily to kill weeds in an area, then I remove it.
Mulch's Secret Weapon
If you want your organic mulches to last a long time, lay down several layers of black/white newspaper or cardboard first before applying the mulch on top. The paper will block light and attract earthworms to the area, which is excellent for the soil. You can also use a little less mulch. Depending on how much rain you get in a year, the newspaper can last for a full year or so.
Simply lay 6-8 layers of the black/white sections of the newspaper on top of the soil and around each plant. Wet it down so that it doesn't blow away before you can apply the mulch. Make sure you overlap the sheets a couple of inches so that light doesn't get in between the sheets.
To use cardboard, remove any tape or staples that might be in the cardboard and cut to fit between plants, overlapping the sheets of cardboard as well. Water well.
Now that the paper is down, add several inches of mulch on top.
How to Mulch
This is where I see the most problems when it comes to mulching plants, especially for trees. Do NOT put mulch right up against the stem of a plant or the trunk of a tree. The mulch will remain moist for days and could cause the stem or trunk to rot.
In the case of mulching trees, do not mulch the roots with more than 2"-3" of mulch at a time. Too much mulch can actually suffocate the roots. That's where newspaper or cardboard can really come in handy. You can lay down the paper and use less than 2" of mulch on top and still stop weeds from taking over.
Mulching around trees is also beneficial to young trees as studies have shown that they grow better the first few years without competition from other plant roots, such as grass.