Mulching is one of the easiest ways to greatly reduce water use in an existing garden.
It consists of spreading a layer of organic matter over the soil surface.
This doesn’t get worked in but acts as a blanket, holding in moisture and reducing weed growth. It prevents a hard crust from forming on the soil surface.
As the mulch breaks down, nutrients are released to build up the soil.
Plants thrive by being slowly and naturally fertilized by the organic mulch. They tend to be sturdier, pest free and bloom abundantly.
Mulch may be spread at any time. To reap the most benefit do it before summer heat sets in.
Before mulching remove all weeds and soak the ground.
For annuals, perennials and ornamental grasses, mulch to a depth of one to two inches.
These plants tend to do better with mulches that contain some nitrogen.
OgoGrow and Nature’s Gold, made from biosolids composted with wood waste, have a fairly high nitrogen content to encourage plant growth.
Before use, animal manures need to be well-rotted to ensure weed seeds are killed off.
Chicken manure is very high in nitrogen so it can burn plants.
It’s best used to layer into the home compost pile to make it rot faster and enrich the compost.
GlenGrow, the city-composted yard waste, is lower in nitrogen than the above options.
We have used it successfully at the unH2O Xeriscape Garden for six years.
Arborist mulch, created when deciduous tree leaves are shredded in with wood, will supply a small amount of nitrogen.
For vegetable gardens, you can use a fairly thick layer of straw or spoiled hay.
Other options are one to two inches of compost. If you make your own compost you will know exactly what you are putting into your food garden.
For trees and shrubs, use four inches. To prevent damage from rodents and diseases, leave space around the trunks/stems so mulch is not touching.
In addition to the flower garden options, wood chips or bark mulch, may be used here if you don’t live in a fire prone area.
These woody mulches can also be used for flower gardens. They only contain carbon but nitrogen can be added by spreading some alfalfa pellets (rabbit food) under the mulch, around each plant.
Do not use cedar or walnut mulch around plants as they contain compounds that inhibit growth of some plants.
Newspaper can be used, usually under another material. The inks are vegetable-based so are safe.
Lawns may also be mulched with one half to one inch of material (e.g. Nature’s Gold) in early spring or fall. This builds up the soil and slowly feeds the grass all season,
The need for chemical fertilizers, which tend to cause a spike in growth, creating higher water needs and more mowing, is eliminated.