Organic Vegetable Garden Mulches

 What is Mulch?

Simply put, mulch is an additional layer of material placed on top of soil that is intended to protect or enrich the soil underneath. Mulch can be created from a wide range of materials and can be tailored for specific climates and plants. At its core, mulch serves as a mechanism for plant protection, weed prevention, and moisture retention. But, because organic mulch itself decomposes, it also serves to enrich the soil. Although mulch is not the most glamorous aspect of gardening, it should not be overlooked—it is an essential aspect of vegetable gardening and overall garden culture.

What is Organic Mulch?

Generally, there are two overarching types of mulch: organic and synthetic. Organic mulch is usually composed of organic plant and/or animal by-products, whereas synthetic mulch is usually made of plastic or rubber. Each type can serve unique purposes, but I will focus on the benefits and use of organic mulch.

What are the Benefits of Using Mulch?

Reduces Weed Growth

Weeds can be a menace to your vegetable garden. Beyond just being unsightly, mature weeds steal the moisture and nutrients from the soil that your vegetable plants need. While it is possible to remove weeds by hand, this arduous task can be reduced through the proper application of mulch. A thick layer of mulch helps keep weeds down by creating an almost impenetrable layer on the soil. This layer will suppress most weeds by creating an environment in which they find it hard to grow.

Conserves Soil Moisture

While weeds are a threat to your vegetable garden, hot dry weather or drought can be an even more deadly killer. One way to combat drought is to apply a plentiful layer of mulch. Mulch retains the moisture obtained from seasonal rains and irrigation and will help to create a more balanced and steady moisture level over time. In other words, it helps ensure there is never too much water or not enough and this consistent moisture level encourages steady plant growth. Finally, mulch can reduce costs and prevent the unnecessary waste of water by requiring less rainfall and/or irrigation. In other words, mulch helps you grow the same plant, with less water.


Keeps Soil Temperatures Stable

The ability of mulch to
stabilize soil temperature is a benefit that is often ignored to the detriment of the gardener. Preventing extreme fluctuations in soil temperatures is critical because certain plants are more sensitive to and/or react inappropriately because of changes in soil temperature. For example, strawberries will stop producing if they get too hot, whereas many cold weather plants will “go to seed” too soon (i.e., when a vegetable plant begins to flower and stops producing vegetables and goes dormant). Mulch acts as a buffer for temperature fluctuations and will provide a more stable soil temperature than would be the case with bare ground. As such, the proper application of mulch will help provide your plants with the most optimal growing temperatures, and extend the amount of time that they are producing delicious vegetables for you to eat!


Reduces Soil Erosion

Soil erosion can create more issues than just washing away all of your good soil, it can cause river pollution downstream and increase your gardening costs by forcing you to continuously buy more dirt. Mulch reduces the amount of water runoff, which helps to keep your garden soil in place. This is especially helpful immediately after cultivation when the soil is loosest and most vulnerable to erosion or on sloping ground. In addition, mulching reduces soil compaction caused by driving rain and overhead watering.


Reduces Disease and Disease Severity

The combination of improved growing conditions, the reduced need to compete with weeds, a reduction in pests, and improved soil quality tend to make garden plants less disease prone and more able to recover when treatment is necessary.


Keeps your Crops Clean

hard rains or forceful irrigation is used, soil inevitably splatters onto your garden plants. Mulches help keep your fruits, vegetables, and flowers in picturesque shape. Plant cleanliness also improves plant health by not moving fungi and bacteria onto your plants and depriving them of a habitation which to grow.


Reduces Fruit and Vegetable Spoilage

RBecause fruits and vegetables grown in organic mulch tend to be healthier, cleaner, and grow more evenly, you will find that less spoilage (e.g. fruit cracking) will occur in your garden and they store longer before spoiling.


Grows Plants Faster

As a result of improved conditions provided by mulching, plants tend to grow more rapidly and mature more quickly. This means you will be able to start eating your home-grown vegetables sooner! Even if you planted your seeds late or are on your second round of planting, you may find that seeds planted in organic mulch will tend to catch up with those seeds planted on time. This increased rate of growth can be enhanced when organic fertilizer (e.g., composted cow manure) is applied before mulching.

Raised Garden Bed With Mulched Paths
Raised Garden Bed With Mulched Paths


Tool for Attractive Landscaping

The selection and use of a good quality mulch can be a tool in creating an attractive background for plantings and tend to make the garden look well-tended. As a side effect, you will find yourself spending more time in your garden, even when the weather condition is less than optimal.


Reduces Manual Labor

Mulch reduces the need to weed, cultivate, irrigate, and treat plants for pests and/or disease significantly and, thus, reduces the level of work required to have a highly productive and healthy garden.

How Much Mulch Should I Use?

Depending on the type of mulch you are using, you may need to use thicker layers of mulch. Looser, less dense mulch needs to be more thickly applied than, heavier more dense mulches, to create the same effect. Normally, a layer between two to four inches is appropriate for most organic mulches. You can apply more mulch in travel paths or between rows for greater weed control.

Common Organic Vegetable Garden Mulch Materials

Organic garden mulches are mulches, which can be cultivated into the soil to improve ground quality during site preparation or at the end of the growing season. Organic mulches may also be moved to the compost pile to complete the decomposition process and then cultivate into the soil. Organic mulches average soil temperatures providing more ideal growing temperatures and soil culture longer. Cultivating in a small quantity of slow release fertilizer (e.g. compost, cured manure, blood meal, etc.) before an organic mulch is applied is highly recommended, as the decomposition process will leach some nitrogen from the soil.


Grass Clippings

Allow lawn clippings to dry before applying to gardens. Fresh, green material may settle and form a dense mat or produce an unpleasant odor. If the lawn has been treated with a broad-leaf herbicide, don’t use the clippings until the lawn has been mowed two or three times after the application. The best source of lawn clippings is a well maintained, non-chemically treated, lawn. Grass clippings from a weed-infested lawn will undoubtedly contain a large amount of weed seed.


Leaves

Leaves should be shredded or composted before applied as a mulch. Shredded or composted leaves do not mat down as readily as whole leaves are less likely to blow away in the wind and decompose more quickly. Shredded or composted leaves are an excellent mulch for vegetable gardens, raspberry plantings, annual flower beds, and around trees and shrubs. Even though the leaves of some trees (such as oak) are acidic, they can be safely used in the yard and garden. The small amounts used by home gardeners have little effect on soil ph. Leaves are a poor winter mulch for strawberries and herbaceous perennials.

Chili Peppers mulched with wood shavings
Chili Peppers mulched with wood shavings


Sawdust or Wood Shavings

Sawdust or wood shavings are easy to apply, weed free, and decompose slowly. Generally, sawdust should be composted or allowed to age/weather for a year before being applied. If fresh sawdust is used, apply only a 1-inch layer and make sure the sawdust doesn’t cake. Also, I have found the local farm supply store an excellent source of clean wood shavings used for animal bedding, usually at a reasonable cost, which makes very nice mulch.


Straw

A straw that is free from crops and weed seed is an excellent mulch for the vegetable garden. Suitable materials include wheat, barley, oat, and rye straw. Straw may provide winter habitat for mice, slugs, and other rodents, so, fall removal and inclusion in a compost bin away from the garden site is recommended. An alternative to removal is to ‘Sheet Compost” the mulch by cultivating the mulch into the soil at the end of the gardening season.


Spoiled HaY

Hay which has become damaged due to exposure to the elements, especially moisture, make excellent mulch provided they have decomposed enough to kill any seed that the hay may have contained. Hay as the same habitat characteristic as straw and should be likewise treated.

Shredded Office Paper Mulch
Shredded Office Paper Mulch


Newspaper and shredded office paper

Newspapers shredded or whole, as well as, shredded office paper may be used in the vegetable garden. When using newspaper sheets, place a layer of 6 to 8 layers sheets between plant rows in the garden. Water the sheets so they stick to one another and to the soil surface, then weigh them down to prevent them from blowing away. I have used shredded office paper from a local office to great effect, once you get used to the color White in the middle of your garden) and your neighbors’ questions. Use, in pathways and around established plants has worked very well; especially, as it was free and did not take up space in the local landfill.

Cleaning up

Mulches should be cleaned up as your garden year progresses to reduce habitat for disease and pests. In general, your vegetable garden mulch should be cleaned at the end of the gardening season, when preparing to succession plant, and upon crop rotation during the year. Mulch may provide a habitat for mice, slugs, and other rodents if left in place during the non-growing season. So, removal and inclusion of old mulch in a compost bin away from the garden site are strongly recommended. If removal and composting is not an option, then vegetable garden mulches may be “sheet Composted” by cultivating the mulch into your garden bed and permitted to compost. However, care should be taken to rotate your garden crops, so that, you do not grow the same in the same place two seasons and/or consecutive succession plantings.

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