Mulch is the ultimate time-saver for gardening, whether you tend to plant beds or vegetable gardens. And while mulching itself can be a pain, it brings many rewards: When done properly, mulch reduces the time it takes to water, weed, and fight pests. Overall, this results in healthier fruits, vegetables, and flowers.
For a more successful garden, be sure to choose the best mulch for the job. Although most types of mulch keep pests and weeds away, some meet the needs of specific plants, trees, or other crops. Before laying down an old mulch, read on to find the perfect type for your garden, as well as tips and advice on how to distribute it properly.
Different types of mulch for your garden
There are two basic types of mulch: organic and inorganic. Organic mulch includes formerly living materials such as chopped leaves, straw, grass clippings, compost, wood shavings, shredded bark, sawdust, pine needles and even paper. Inorganic mulch includes black plastic and geotextiles (landscaping fabrics).
Both types of mulch discourage weeds, but organic mulches also improve the soil by decomposing. Inorganic mulches don’t decompose and enrich the soil, but that doesn’t necessarily mean they aren’t a smart option for your garden. Example: black plastic, a popular type of inorganic mulch, warms the soil and gives off heat overnight, keeping vegetables warm like eggplant and cherry tomatoes comfortable and vigorous.
Here are the six most common types of mulch:
Wood chips or shredded leaves
You can buy bags of decorative wood chips or shredded bark at a local garden center to mulch your flower garden and shrub borders. For a cheaper option, call your local tree care or utility company to see if they have additional wood chips on hand. Or if you are really planning ahead, shred your Christmas tree instead of throwing it at the curb.
If you have trees on your property, shredding the fallen leaves creates a nutrient-rich mulch at no additional cost. You don’t need a special machine either: a lawnmower with a bagger will pick up the leaves and cut them to the perfect size for mulching.
Spread wood chips or mulch of shredded leaves anywhere on your property, but it looks best in flower beds, shrub borders and garden paths. Of course, it is at home in a wood or a shady garden. Keep in mind that wood chips are not a good choice for annual vegetable and flower beds, as they will bother you when you dig the beds each year.
Grass clippings are another readily available mulch, although it is a good idea to keep some of the clippings for use as natural lawn fertilizer. When you have leftover grass, use it as a nitrogen-rich mulch in vegetable gardens.
Give your compost another goal: if you have more, use it as mulch. It will enrich the soil and make the plants happy, but keep in mind that when any type of mulch is dry, it is not a welcoming place for plant roots. This means that you may want to reserve your compost to spread it in a thin layer around the plants and cover it with another mulch, like chopped leaves. This allows the compost to stay moist and biologically active, providing maximum benefit for your vegetables, fruits, or flowers.
Straw or hay
Mulching a vegetable garden with black plastic film can do wonders. When spread tightly over a smooth soil surface, black plastic transmits heat from the sun to the soil below, creating a microclimate about three degrees warmer than an unmulched garden. Because the plastic film remains hot and dry, it protects the fruits of climbing plants such as strawberries, melons and cucumbers from rot. And, of course, mulch prevents weed growth and retains soil moisture.
Infrared transmission plastics (IRT) cost more than standard black plastic, but they can lead to even higher yields. These plastics warm the soil as well as the transparent plastic, but also control weeds as effectively as black plastic. In raised gardens, place a sheet of plastic over the entire bed. Bury it around the edges or weigh down the plastic with stones. Then, drill holes with a bulb planter and fill with plants or seeds. Since water cannot penetrate the plastic, you cannot rely on rainwater to properly hydrate your plants. Instead, lay soaking pipes or drip pipes on the floor surface before depositing the plastic.
Be careful not to use mulch under the shrubs, especially since plastic destroys the long-term health of the shrubs. Because water and air cannot get into the plastic, the roots grow very close to the surface of the soil – sometimes just below the plastic – in search of moisture and oxygen. Shallow roots suffer from a lack of oxygen and moisture and extreme temperature changes. Over time, plants decline and die.
Geotextiles, also called landscaping fabrics, allow air and water to penetrate the soil below while preventing weeds from moving up. But there are still some drawbacks: when exposed to light, geotextiles degrade over time. To make them last longer, cover them with a second mulch (they are ugly, so you will want anyway).
Similar to plastic mulch, keep geotextiles away from shrubs. Roots and shrub weeds grow in the landscape fabric, which means you will need to tear the landscape fabric when removing it.
How to mulch properly
There are two cardinal rules for using mulch to control weeds. First, put the mulch on already weeded soil, and second, put a layer thick enough to discourage new weeds from crossing.
A four-inch layer of mulch will discourage weeds, although a two-inch layer is usually sufficient in shaded areas. If you know a garden bed is full of weed seeds or perennial roots, try a double mulching technique to avoid a weed explosion. To do this, put the plants in place, water them well, spread the newspaper and cover it with mulch.
Mulch that also retains moisture (such as wood chips) can slow the warming of the soil. In the spring, remove mulch from perennials and bulbs for faster growth. A damp mulch stacked against the stems of flowers and vegetables can cause them to rot; keep the mulch about an inch from the crowns and stems.
Mulch stacked against woody stems of shrubs and trees can also cause rot and induce rodents (such as voles and mice) to nest there. Keep the deep mulch pulled about six to 12 inches from the trunks.