- Always edge before laying mulch. This will give the beds a clean, defined appearance and keep the mulch from running off into the grass and onto pavement when it rains.
- Applying a pre-emergent before laying the mulch will greatly reduce the number of weeds that will pop up throughout the year.
- This chart will help you determine how much mulch you will need to buy. Add the square footage (length X width) of all the areas you will be mulching together, then divide that number by the corresponding number on the chart. The number you get is the number of bags or yards (a scoop is usually about a yard) you will need to mulch your beds.
|Desired Depth||One – 3 cu. Ft. bag||One – 2 cu. Ft. bag||1 cubic yard|
|1″||36 sq. ft.||24 sq. ft.||324 sq. ft.|
|2″||18 sq. ft.||12 sq. ft.||162 sq. ft.|
|3″||12 sq. ft.||8 sq. ft.||108 sq. ft.|
|4″||9 sq. ft.||6 sq. ft.||81 sq. ft.|
In Your Backyard
Mulching is one of the simplest and most beneficial practices you can use in the garden. Mulch is simply a protective layer of a material that is spread on top of the soil. Mulches can either be organic — such as grass clippings, straw, bark chips, and similar materials — or inorganic — such as stones, brick chips, and plastic. Both organic and inorganic mulches have numerous benefits.
- Protects the soil from erosion
- Reduces compaction from the impact of heavy rains
- Conserves moisture, reducing the need for frequent watering
- Maintains a more even soil temperature
- Prevents weed growth
- Keeps fruits and vegetables clean
- Keeps feet clean, allowing access to garden even when damp
- Provides a “finished” look to the garden
Organic mulches also improve the condition of the soil. As these mulches slowly decompose, they provide organic matter which helps keep the soil loose. This improves root growth, increases the infiltration of water, and also improves the water-holding capacity of the soil. Organic matter is a source of plant nutrients and provides an ideal environment for earthworms and other beneficial soil organisms.
While inorganic mulches have their place in certain landscapes, they lack the soil improving properties of organic mulches. Inorganic mulches, because of their permanence, may be difficult to remove if you decide to change your garden plans at a later date. Therefore, this tip sheet is limited to the use of organic mulches.
You can find mulch materials in your own yard! Lawn clippings make excellent mulch. While not particularly attractive for a flower bed, they work wonderfully in the vegetable garden. The fine texture allows them to be spread easily even around small plants. However, grass clippings are becoming scarce because of the increased popularity of mulching lawn mowers that provide many of the same benefits of mulching to lawns. Newspaper, as a mulch, works especially well to control weeds. Leaves are another readily available material to use as mulch. Leaf mold, or the decomposed remains of leaves, gives the forest floor its absorbent spongy structure. Compost makes a wonderful mulch if you have a large supply. Compost not only improves the soil structure but provides an excellent source of plant nutrients.
Bark chips and composted bark mulch are available at garden centers. These make a neat finish to the garden bed and will eventually improve the condition of the soil. These may last for one to three years or more depending on the size of the chips or how well composed the bark mulch is. Smaller chips tend to be easier to spread, especially around small plants. Depending on where you live, numerous other materials make excellent mulches. Hay and straw work well in the vegetable garden, although they may harbor weed seeds. Seaweed mulch, ground corn cobs, and pine needles can also be used. Pine needles tend to increase the acidity of the soil so they work best around acid-loving plants such as rhododendrons and blueberries.
When to Apply Mulch
Time of application depends on what you hope to achieve by mulching. Mulches, by providing an insulating barrier between the soil and the air, moderate the soil temperature. This means that a mulched soil in the summer will be cooler than an adjacent un-mulched soil; while in the winter, the mulched soil may not freeze as deeply. However, since mulch acts as an insulating layer, mulched soils tend to warm up more slowly in the spring and cool down more slowly in the fall than un-mulched soils.
If you are using mulches in your vegetable garden or flower garden, it is best to apply them after the soil has warmed up in the spring. Cool, wet soils tend to slow seed germination and increase the decay of seeds and seedlings.
If adding additional layers of mulch to existing perennial beds, wait until the soil has warmed completely.
Mulches used to help moderate winter temperatures can be applied late in the fall after the ground has frozen but before the coldest temperatures arrive. Applying mulches before the ground has frozen may attract rodents looking for a warm over-wintering site. Delayed applications of mulch should prevent this problem as, hopefully, the creatures would already have found some other place to nest!
Mulches used to protect plants over winter should be loose material such as straw, hay, or pine boughs that will help insulate the plants without compacting under the weight of snow and ice. One of the benefits from winter applications of mulch is the reduction in the freezing and thawing of the soil in the late winter and early spring. These repeated cycles of freezing at night and then thawing in the warmth of the sun cause many small or shallow rooted plants to be heaved out of the soil. This leaves their root systems exposed and results in injury or death. Mulching helps prevent the rapid fluctuations in soil temperature and reduces the chances of heaving.