Mulching the Vegetable Garden

There are many reasons to mulch your vegetable gardens, and many different organic materials you can use to add even more benefit to mulching

Mulching our vegetable gardens, just like our flower gardens, produces many important benefits.

• Mulching edible gardens reduces weeds, so we will spend very little time on the tedious chore of weeding. Those weeds consume important moisture and nutrients that our plants need.

• Mulching retains moisture in the soil, so we won’t have to water so much.

• Mulching keeps the soil cooler and therefore our plant roots.

• Mulching increases insect activity, which returns and mixes nutrients to your soil.

• Mulching reduces soil splash from rain and overhead sprinkling that can spread fungus and disease.

• Mulching the edible garden keeps it looking neat.

• Mulching the edible garden with the right organic materials will keep your soil, and therefore your vegetables, healthy and vigorous.

And what exactly is the “right” organic material that is best for mulching our vegetable gardens? Choosing the best mulch is important and may depend on the condition of your soil, climate conditions, availability, cost and personal preference. So let’s evaluate natural mulches and the benefit that they provide. Then you can select, or even combine, mulching material based on your needs and availability of materials.

Straw Mulch

Straw is a common mulch for vegetable gardens. It breaks down relatively quickly to add nutrients to your soil. The water retention of straw is relatively low and permeability is high, so it is an excellent texture additive for clay or silt soil. In one season the straw will begin to decompose so the depth will thin by end of season. Turn the straw into the soil either very late in the season or as soon as the soil thaws the following season. DO NOT USE AUTUMN DECORATIVE HAY BALES! They are full of weed seeds! Stick with good quality straw bales, which have become widely available for straw bale gardening.

Leaf Mulch

Shredded dry leaves are great for mulching. They quickly increase the organic matter in your soil once they have decomposed. Dry fall leaves ill decompose fairly quickly if they are ground fine in a mulching vac. Running over leaves with a mulching mower and collecting them in the mower bag will give you rougher material that will last longer. Whole dry leaves may not stay put well in windy areas and will compact in wet weather, preventing moisture from reaching your soil. Autumn leaves are certainly easily acquired and free! I store a few large paper lawn bags in the garage for spring.

Compost Mulch

If you are able to produce backyard compost, that is the best possible food for your plants. Loaded with nutrition packed kitchen and garden scraps with fall leaves and grass clippings, home made compost will feed your soil and plants with a broad spectrum of nutrients. Other than a minimal expense for a bin, producing compost is free and easy. It quickly begins to benefit your soil and feeds your plants over a long period of time. Avoid putting seeds into your compost. If the compost does not get hot enough you will have many volunteers sprouting in your garden. I also find that applying pretty rough compost as a top mulch will last longer as a weed barrier and your plants will love it as much, if not more, than a completely finished fine compost.

Grass Clipping Mulch

Fresh grass clippings will rot and smell rather than decompose when applied in a thick layer. If you want to use grass clippings collected by your mulching mower, add them to your garden in thin layers so they have a chance to dry out. You can build the layers slowly. Once properly applied, grass clippings can add nitrogen to the soil fairly quickly and retains moisture very well. Grass clippings are perfect garden mulch for sandy soils. They will decompose quite rapidly but adding layers though the growing season is easy enough, and free! Do not use grass clippings if your lawn has been treated with pesticides, herbicides or fertilizer.

Bark and Wood Chip Mulch

Wood mulch is quite commonly used in all types of gardens. Bark and wood chips can decompose quickly or be long lasting depending on whether it is hardwood or softwood, large chips or shredded pieces. As it decomposes it will generally add low to medium levels of water retention so that can be a good texture amendment for clay or silt soils. The nutritional value of decomposing wood is broad, but be aware that finer wood such as sawdust will deplete nitrogen from your soil as it decomposes. Most wood chip mulches actually decompose so slowly that nutritional benefit is somewhat minimal. Bark and wood chip mulch is readily available, but of course you will have to replenish it and pay for it.

Pine Needle Mulch

If you happen to have access to lots of pine needles, they really can provide a great mulch. They stay put well even with heavy rain and they decompose slowly. However, pine needles can add acidity to your soil and vegetables in general prefer alkaline soil. Test your soil pH and if it leans heavily alkaline pine needle mulch may not be a problem. If you mulch heavily and repeatedly with pine needles you may need to add lime to neutralize the acidity. Check your pH occasionally.

Selecting your Mulch

When choosing mulch, select a natural organic material that is easy for you to use and acquire and that will benefit your conditions as much as possible. Unless your conditions are extreme any of these natural mulches will benefit your soil and gardens. Avoid heavy materials of course, and inorganic materials. You want to be able to easily move for planting such as successive and seasonal planting as well as benefit the soil nutritionally.

Plastic and landscape fabric should be avoided at all cost in a vegetable garden. If you do want to lay down a barrier between soil and mulch, use thick layers of newspaper or cardboard. They will decompose and add texture, but no nutrition, to your soil. This method is not especially accommodating for planting through the season. You might prefer to save this method for your flower gardens.

When applying your mulch do not spread it right up to your plants as it can encourage disease, rot and fungus. Leave at least an inch of bare soil around each plant so them stem gets good air movement to stay dry. Mulch most heavily between the rows.

Remember that any mulching material will take some time to break down and add nutrients to the soil. A slow release granular fertilizer should be applied according to directions.

Dry mulching material that is incorporated into your soil will use some nitrogen to finish breaking down in the soil. If you dig the mulching material into the soil at the end of the growing season there is plenty of time for the decomposition to complete before the next planting season. If you wait to dig it in before the next season, be sure to do so as early as possible when the soil thaws.