Using Straw as Mulch
Straw is one of the most readily available and versatile materials for use as mulch. The benefits are numerous, the downsides are minimal, and it’s difficult to get wrong.
5 Benefits of Straw as Mulch
- Soil Temperature
- Moisture Retention
- Disease Prevention
- Price & Availability
- Enriches Soil Ecosystem
Straw Insulates Your Soil
One of the primary benefits of straw as mulch is it’s ability to regulate soil temperature. This is most important in times when temperatures fluctuate widely.
In the summer, straw will protect the soil from the sun, shading it while still allowing access to the light hungry leaves.
In the winter straw does the opposite. Straw will insulate the soil keeping it a more consistent temperature. In the early stages of winter, after the first real frost, you can apply mulch over perennial plants. The benefit here is that if you get an occasional warm day, your plants will remain dormant for the season.
Straw Ensures Moisture Retention in Plants
Complimentary to it’s insulating properties, straw will go a long way towards retaining moisture in your plants.
As the sun bakes your soil, moisture is drawn out. If your soil is covered, it stays cooler and also contains moisture that would be attempting to escape.
The straw mulch itself will hold some of it’s own moisture, ready to be made available to the plants and soil.
In the winter, if soil gets overly cold it can begin to form cracks. These cracks can expose plant roots to harsh cold and wind that may be damaging to them.
Straw again acts as a barrier between the elements and the developing root system of your plants.
In a featured study by the Soil Science Society of America Journal the effects of straw on the growth of corn and it’s moisture retention qualities are detailed. The results were stalks of corn that were 64cm taller and produced 42 more bushels per acre on average than corn that hadn’t been mulched.
How Does Straw Prevent Plant Disease?
A hidden benefit to straw mulch is the protection that it provides against soil borne diseases.
The way soil borne diseases reach your plants is typically when there is contact, either direct or indirect between your plants leaves and the soil.
Direct contact happens when leaves rest on the soil or are low enough to touch the soil.
Indirect contact is the contact that is usually not addressed. Indirect contact happens most often with the presence of water. During rain, or routine watering, water droplets that make contact with diseased soil can splash onto the leaves of your plants.
Using straw creates a physical barrier between the soil and plant leaves. Leaves can rest atop a bed of soil without making contact, and water travels through the straw before making contact with soil preventing the soil to leave splashing.
Is Straw Expensive & Where to Find It?
Straw is not incredibly cost prohibitive. Local to me in South Central PA, I can purchase a 50lb bale from Tractor Supply for around $18. This is more than enough for my gardening needs.
You can also purchase straw in smaller bale size, but the cost remains at around $16 as this product is much more convenient.
Depending on where you live, you can also buy direct from farm and your cost will be greatly reduced. One consideration here is that you’ll be able to determine if and what type of pesticides could be in your straw.
Is Straw Mulch Good For Your Soil?
Although primarily carbon based, straw can actually add a lot to your soil ecosystem especially as it breaks down.
Straw also provides an inviting source of food for worms as well as beneficial fungi.
The worms that are attracted to the cool, moist mulch will soon make their homes in the soil below, aerating and fertilizing your soil. These worm castings will do the job of adding rich nitrogen to the soil, further curbing the worry about the carbon content of straw.
When Should You Apply Straw as Mulch?
There isn’t a wrong time to mulch, however there are distinct advantages to mulching in particular seasons.
In both Spring and Summer you really gain the benefits of sun protection and water retention for your soil. If you get your straw down early enough, you’ll also get a head start at weed suppression.
Fall is sometimes considered to be the best time to apply straw as mulch. Applied in the fall straw has enough time to begin breaking down over the winter in order to jump start the soil enrichment process for planting in the spring.
Winter is an often forgotten time to apply mulch. Applying in the winter provides the consistent soil temperature to encourage healthy dormancy in pants.
If you live in a more arid climate, straw mulch is a wonderful aid in xeriscaping.
How Do You Use Straw as Mulch?
For weed suppression you can layer on 2-4 inches thick to occlude sunlight. It is a best practice to keep the straw about a 1/2 inch from the stem of a plant or base of a tree to reduce the risk of rot.
If you’d like your straw to be more effective instantly, mulching with a lawn mower to break it down more quickly is a great option. Straw is soft enough to not worry about your mower blades. There are available however, mulching blades that are incredibly helpful for several different uses around your property.
Straw as Mulch over Grass Seed
If you’re spreading new grass seed, straw is my number one pick for a protective top cover.
Straw will keep your grass seed in place. A windy day can do a number on new grass seed.
Straw will protect the fragile seeds from the sun, and lock in moisture that is essential to germination.
You can deviate from the 3-6 inch rule for most application and scale back to about a 1/4 inch. This keeps the cover loose enough to still allow some light and air through and not suppress the new growth.
Straw is available in several convenient forms such as straw matts, specific to covering grass seed.
I go into greater detail in my post titled Mulch Over Grass Seed as to why straw is my number one pick for this application, and definitively cover all other options available to ensure successful germination of grass seed.
Other Uses for Straw
Straw can be a great addition to your compost heap. It acts as a “brown” or carbon source. Straw is nice and light and will make it easy for your compost to remain aerobic.
Straw is also an excellent bedding material for a number of animals including chickens and quail. When using straw for these animals, they will add a natural fertilizer to the straw which will supercharge your compost, and can even be planted into directly.
If you’re ready to find out more ways to put mulch to work in your garden, Discover 11 Handy Uses For Mulch in The Garden next.
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