Before you can answer that question there are a few more to ask:
What is mulch?
Mulch is any material applied to the surface of soil to cover it. There are many materials that can be used, plastic sheeting, landscape cloth, or an organic material like wood or bark chips. We use wood and bark chips, but not from pine trees because they can be too acidic.
Check out these reasons why Garden City suggests you should mulch:
- holds moisture in the soil, protecting drying out too quickly
- reduce weeds from taking over
- moderates soil-temperature fluctuations
- organic mulches improve the soil’s health, as they decompose.
- make the garden bed look more attractive
When should I mulch?
NOW – at the beginning of the growing season mulches help warm the soil and retain heat that can be lost in the cool nights. This encourages growth of early seeding and transplanted plants.
Through the growing season mulch helps to maintain soil moisture and temperature. It also prevents the growing of weeds from seeds.
Mulch applied In fall and winter helps to delay too early growth of perennial plants in the spring and prevents growth in winter during warm spells, which limits freeze thaw damage that can can literally push plants out of the ground.
How is mulch applied?
It is applied to bare soil and around plants.
If you apply too much (over 3”) or apply a deep layer up against tree and shrub trunks, little critters may decide this is a great hiding spot for rodents, especially during winter.
What about my lawn?
If your grass is less than 3” tall then let the clippings fall where they may. The clippings decompose quickly, returning nutrients to the soil within two weeks after mowing. Trace minerals including phosphorus, potassium and nitrogen (which is the most expensive part of lawn fertilizers) are then bioavailable. So, it pays to leave clippings when they are short. Grass clippings don’t cost anything, are easy to apply and decays quickly.