In many places around the country, autumn trees are extremely beautiful with brightly colored leaves consisting of reds, oranges, yellows and greens. The cooler weather of fall is so relaxing following the hot summers in the U.S., but what follows can be a chore. The autumn leaves will soon fall off the trees and we must decide what to do with them.

With that said, it is important to note that leaves hold a lot of nutrients that can be returned to the soil through decaying leaf organic matter. It releases Nitrogen, Magnesium, Potassium, and other nutrients back into the soil for plants to use. It also releases into the atmosphere carbon dioxide it absorbed earlier in the year and converted to carbon compounds. In fact, according to Massachusetts Institute of Technology, decaying organic carbon from natural sources contributes to more than 90 percent of the carbon dioxide released into the earth’s atmosphere and oceans. Fallen leaves contribute to this effect and are reabsorbed and used again by most all plant life, including newly sprouted leaves each spring. (check out why Organic Matter Matters here) 

However, if you are a sports field manager or homeowner and have worked hard to maintain a beautiful lawn, then leaving the leaves on the grass is not an option. The leaves can eventually smother the grass leaving even more problems to correct come spring.

So what are your options? Assuming you are going to do the work yourself, you are looking at two primary choices. If you have a lot of large shade trees, then removing the leaves from the grass is the best option. If you have a few scattered, smaller trees, then mulching them in place may be the best choice. But if you decide to remove them you are faced with other choices that depend on your abilities and cost factors. Not everyone can afford the expensive professional equipment used on prestigious country clubs. Even city golf courses and most homeowners can struggle to get the work done on a smaller budget. Here are a few helpful examples.

 Cardboard Method that Replaces Raking

If you have a small area to maintain and are in decent shape, you can rake them. A shortcut to raking is using a thick flattened cardboard box or a piece of lightweight paneling or something similar. With the cardboard at a 40 degree angle in front of you, walk and push the leaves to a primary location. On a flat surface you can remove 6 ft of leaves in one sweep. I have seen huge lawns cleaned up using this method in less than an hour. Once the leaves are piled up they can be bagged or burned in place if your laws allow it.

 Lawn Vacuums

Lawn Vacuums are the name given to the various, pull behind, leaf vacuum systems. These are large storage boxes that hold leaves that are sucked up through a large diameter vacuum tube attached to the mower discharge vent. There are smaller homeowner systems up to larger commercial systems. Each one has a motor attached to the storage box that pulls the leaves from the discharge vent on the mower into the box. One of the better lawn vacuums on the market is the Cyclone Rake. The storage box holds up to 415 gallons of shredded leaves and comes with motors as large as 10 hp.

The lawn vacuum draws the leaves though a 6″ – 10″ tube, depending on the model. At the end of the tube is a blade that creates the vacuum and shreds the leaves even more. So be sure to walk the property and remove all the limbs and sticks that could get stuck in the vacuum tube or you will spend valuable time cleaning out the tube. When the storage box is full it can be easily dumped onto a trailer or somewhere on your property used for disposal.

The better systems work great and can remove leaves from a shaded lot the size of two or three acres in just a few hours. It is a time saver and far less strain on your body.

 Mulching Leaves

Leaves can also be mulched and left on the grass. The keys are to mulch when the leaves are dry and to keep the leaves under the mower as long as possible. If your mower allows you to close the discharge vent, this doesn’t allow the side discharge of leaves. The result is that they are mulched repeatedly until they filter out under the mower.

Can you have too many leaves to mulch? I do believe so. While it is possible to mulch huge amounts of leaves, you can end up with several inches of shredded leaves sitting on the grass and the effect can be about the same as having left the leaves untouched.

Important Information that can affect your decision on mulching: Leaves are completely broken down by soil microorganisms. The bacteria responsible for most of the work are most active in summer. If you have enough soil moisture in summer, the microbes are going at it full speed. Early spring and fall they are slow or are slowing down considerably. In winter, in most of the U.S., they are either inactive or close to it. This is why leaves that fall in Autumn are still there in the spring. They decompose rapidly as the weather warms.

Therefore, in the fall and winter, an inch or so of shredded leaves is fine on the grass that is mowed higher than a couple inches. It can help insulate the soil as well. Having several inches of shredded leaves can suffocate the grass by keeping moisture and air from reaching the roots.

 Hand-Held Leaf Blowers

If you have just a few small trees or even a single shade tree, you can use your hand-held leaf blower to blow the leaves into a pile. You can put a tarp in the back of a pickup truck and load the leaves onto the tarp. If your city has a dump station, simply pull the tarp and all the leaves come with it.

 How to Make Compost in 14 – 18 Days

This method was developed by the University of California at Berkeley and has been modified over the years. Composting leaves is a great way to reuse your leaves on your lawn and garden. It adds valuable nutrients and organic matter needed for beneficial microbes and earthworms, etc. The 18 day method is a “Hot Compost” method as compared to the cold compost methods used by most people that can take up to 12 months. Using the hot compost method kills any damaging bacteria and weed seeds as well. The compost will be much finer with smaller particles and ready to use.

Here we go: The basic facts. You simply cannot make a pile of leaves and expect it to compost quickly. You need to have a good C:N (Carbon to Nitrogen) ratio. Don’t let this confuse you. It is really easy.

1. Determining the C:N Ratio of materials: Leaves have a moderately high carbon and low nitrogen ratio. The higher the carbon to lower nitrogen material breaks down slowly. Fallen trees, branches, etc have the highest C:N ratio and can take years to break down naturally with a 500:1 to 1200:1 C:N ratio. As for leaves, depending on the  leaf type, it can be as high as 80:1 C:N ratio and as low as 40:1. This means it can break down more slowly. You will need to add material with a low Carbon to Nitrogen (C:N) ratio to speed the process. Freshly cut grass, some garden plants, vegetables, fish, animal manure, etc will break down fast and speed the process. I put freshly cut grass in a large plastic bag during summer years ago and in a couple hours it was so hot that you couldn’t touch it. I have included a website below that shows the C:N ratio of many different materials. (learn more about Organic Nitrogen in Soil here)

2. How to Mix the Different C:N Ratio Materials: The ratio of high and low C:N should be a 1:2 ratio. This is shown as a 1 + 2 = 3. An example is one part manure added to two parts leaves. First lay down a layer of leaves less than a foot thick. Remove large sticks.

Next add 1 part mown grass, garden plants or vegetables, or manure. Blood meal fertilizer has an extremely low C:N ratio at 3:1 and can heat up quickly. Cover with another 2 parts of leaves. Repeat this until you have a 3 to 4 ft tall by 3 to 4 ft wide stack of leaves to grass/manure mixture. There needs to be sufficient amounts of Nitrogen for it to heat up and work.

It is possible to have too much nitrogen. If this happens add newspaper or sawdust internally within the pile to slow it down.

3. Next,  after building the pile as described, water down the entire stack until thoroughly wet and water is flowing from the bottom of the pile. You can put extra compost activator (Turf Formula® is an excellent choice) in the middle section to start the process more quickly. This can be crab waste if you live near the gulf, fish, or even store bought activator.

4. Leave the pile for 4 days. Then turn the compost pile using a pitch fork. If you are expecting storms to come through you may need to cover the pile with a tarp to keep it from getting flooded again.

5. Turn again after four days. If moisture is still good, leave it alone. If not spray a little more moisture. It shouldn’t be wet, just damp. You can squeeze some of the compost to see if any moisture is on your hands.

6. Check the internal temperature. It should reach 150 degrees. When this happens, start turning every two days until the 18 days are over. The compost should be cooled, no harmful bacteria or weeds seeds.

The compost should be dark, smell earthy, and be well broken down. It can be used on your gardens, lawn, or wherever you need compost. With a little experimentation you can have the perfect blend that composts rapidly.

There are numerous articles that can be found online. Here are two sources I used:

• https://norganics.com/index-2/technical-articles/carbon-nitrogen-ratio/
• https://vric.ucdavis.edu/pdf/compost_rapidcompost.pdf

One last thought to consider – AgriGro®’s products provide a big help in this area by boosting the native microbial life to improve breakdown of insoluble nutrients. Products like Turf Formula® work to provide an immediate shockwave to your compost allowing the natural microbiome to unlock higher nutrient availability to your spring turf. 

Russ James
AgriGro Turf Specialist

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Sources:
Lawn Care Academy, Russ James, Photosynthesis of Turf Grasses
Fundamentals of Turfgrass Maintenance, Photosynthetic Pathways Page 11, Dr. Nick Christians