Choosing organic mulch for your raised garden bed?

Organic mulch plays an important role in the planting of raised garden beds and other plant beds. Some plant roots are not heat- or cold-tolerant, and mulch can provide a comfortable temperature for plant roots. There are also some plant roots that need to be kept cool, branches and leaves need sufficient light, and it is particularly important to add mulch at this time.

Coverage advantage

reduce water evaporation

There are many benefits to using mulch. In summer, mulching keeps the soil moist and reduces evaporation, so gardeners don't need to water as often. Use mulch so the soil doesn't dry and hard after baking in the sun all day.


The covering is moisturizing. In some places with high temperature and strong sunlight, soil moisture dissipates quickly after watering. In these dry, hot places, it's best to use a mulch to keep moisture in. However, if the garden is hot and humid, mulching is not necessary as it can lead to mold growth.

root protection

Wood veneer, sawdust and fallen leaves are common mulches in our lives. Over time, this mulch will slowly break down into more humus-rich decaying soil. These decomposed substances contain nutrients that benefit the plant's root system.

reduce weeds

Mulch also keeps weeds away. If mulch is added to raised garden beds, light does not reach the soil and weed germination is inhibited. This prevents weeds from absorbing nutrients from the plant, which is a great help for garden bed plants.

keep warm

A thick layer of mulch can be applied to the soil surface before winter frosts arrive to help prevent frostbite on plant roots. The thickness of mulch on raised garden beds is usually about 1 inch.

If you use mulch to protect the base of the rhizomes from frostbite in winter, you need more than 2 inches to be effective. If the mulch is spread too thick, it can cause the roots to suffocate.

Improve soil nutrients

In addition, organic mulch will slowly decompose over time, so the structure and fertility of the soil will increase. So adding mulch can help improve soil quality and reduce fertilizer use.

type of covering


Veneer is a common and environmentally friendly covering material, and its sources are also very wide. Wood veneer is one of the more effective mulches for garden planting and decomposes relatively slowly. Pine and fir bark decomposes more easily than regular chopped bark. To use the bark as mulch, it needs to be processed into finer wood chips for better decomposition.


fresh grass

Fresh grass is freely available from the garden, it decomposes quickly and can be converted into soil nutrients. If you use fresh grass as mulch, you can first lay a thin layer on the raised flower bed and wait for it to dry before laying a layer to prevent the fresh grass from rotting. And don't use Bermuda grass.

Here are a few things to keep in mind when using grass as mulch:

Avoid pulling weeds in wet weather and do not leave them in the planting area to prevent them from regrowing.

Remove the long roots from the planting area and dry them in the sun. After drying, it is burned into grass ash (grass ash is a rare organic nutrient because it contains almost all the mineral elements that plants contain).

Pull weeds a day or two after the rain, when the soil is looser and easier to pull out.


Like other natural mulches, hay adds nutrients to the soil as it decomposes. However, it should be noted that when using hay mulch, try to avoid using seeded hay to prevent the seeds from germinating and turning into weeds.


Straw is a clean and hygienic organic mulch because it keeps the soil from contacting the fruit. Especially in summer, laying a layer of straw mulch on the garden bed can have a particularly good cooling and sun protection effect.

Among the grass mulch options, straw is the preferred mulch. On the one hand, without the risk of weeding, it has all the advantages of a natural mulch.

fallen leaves

Fallen leaves are an extra gift from nature and a great choice for raised garden beds. It is advisable to shred and chop them before using fallen leaves for mulch. Not only will this decompose faster, but it will also keep the leaves from clumping during the decomposition process.


Compost looks like soil, but the compost mulch is a little darker in color than soil. Compost breaks down quickly, both fertilizing and moisturizing the soil. If you buy compost, it's relatively inexpensive. Of course, compost is easy to make, and you might consider making your own.

In raised flower beds, compost can be placed in the middle layer to allow the plant roots to fully absorb nutrients, but it can also be placed at the top for a certain moisturizing effect. There are also many gardeners who plant directly on the ground for composting.

pine needles

Pine needles are natural mulch that can be continuously collected under pine trees. Placing some pine needles around plants on the ground or on top of a garden bed will also keep soil moisture and pests away, such as common snails.


Sawdust is also suitable for use as mulch and can be used in garden beds or in the ground. If you're using sawdust for mulch, it's best to choose sawdust made from natural wood. Sawdust itself is acidic and can be used on soils that prefer acidic soil, such as blueberries. It can be placed around shrubs and trees. However, if sawdust is used, the soil can easily be deficient in nitrogen fertilizer, so the use of sawdust should not be too much, and some other mulch can be mixed in to improve the situation.

Inorganic Mulch: Pea Gravel and Rock

Pea gravel and rocks are inorganic materials, so they won't decompose in the garden, which also means they won't improve the soil over time, but they can be effective at preventing weed growth.

Covered rocks can get hot, so dry-loving garden plants, such as ornamental grass plants, on the ground are often covered with stones.

Use of coverings

How to add mulch

If you are seeding, add 2-3 inches of mulch on top. It's best to wait for the seeds to germinate and grow a few inches tall before placing mulch. If you cover with mulch immediately after planting, it blocks the sunlight needed to germinate, making it difficult for the seeds to germinate.

It is also important to place mulch around the crop without covering the seedlings. Leave an inch of space for the rhizomes of the plants. If you use straw, sawdust or leaves as mulch, they may absorb some nutrients from the soil. So adding some organic fertilizer to the soil before adding mulch works.


The mulch on the soil needs to be maintained every year. You can use garden tools to loosen it up and keep it fresh for longer. NOTE: If you are on a raised garden bed

With a garden grid or watering grid, you need to add watering time to your daily watering. Because the mesh will affect the water penetration time.


Mulch will gradually break down on the soil surface, so new mulch needs to be added every year for better performance. The best times to change mulch are in spring and fall after planting.