I love the fall. The shorter and cooler days, the beauty of the leaves changing and the preparation for winter, all nourish my soul. During this time of year it is not uncommon to see non-biodegradable trash bags full of leaves at then of every drive way. I have never liked seeing that. The whole thought process just doesn’t make sense on any level.  And then there’s the flip side; those who do nothing and let piles of leaves sit on their lawns over the winter to suffocate the turf and breed molds and fungus in those anaerobic spaces… again, I don’t see the value there either.

This is one of those “manicuring conundrums” that plague our industry. The naturalist approach would be to just leave them there and let the biology do the heavy lifting. That’s fine, but only if these are completely non-manicured areas that can remain natural and untouched by human hands. The reason for that is quite simple really,  leaves provide both insulation and food for spring in the wild. The carbon and nutrients will get used up and create topsoil over the years and years that go by and any nut or seed that fell just prior to the leaf drop will be able to “settle in” to a growth zone for the spring. This would be the only way that leaving the leaves makes sense.

As it typically goes, we have raised beds, mulch and other medium that surround the bases of our trees in landscaping. That mulch buffer or pine straw or whatever is acting as that insulating blanket already even if the material isn’t “compostable” it is performing one natural function. In turf areas, whole leaves are a terrible option because you have created a “smothering” environment similar to putting out a fire with a blanket. If at anytime there is something covering turf that is larger that the blades, you are going to kill that crown. The fire goes out.

The agronomic value of leaf tissue is high and should be utilized, not removed, but made smaller to become viable food for anything it ends up on. For years I have taken a vacuum blower and kept the front open to allow the leaves to be ground up and then fired back into my bedding areas. The small bits of leaves become quickly digestible, and do not have the ability to form suffocating piles where they end up. There is very little leaf litter around when spring comes because of the grinding method.

The same goes for lawns, leaves make a wonderful food and carbon blanket for the winter or in areas where the grass doesn’t go fully dormant. Its decay will lead to a more robust lawn as the years go on. This is a free gift of carbon that should be utilized. While the nitrogen of the leaf content may be next to zero, the build up of plant available N for the spring will spike with this type of practice. The more often we take away the free gifts that are given, the more our soils give up carbon to the atmosphere without replenishment.

This is a good time to transition to compost teas as they pertain to turf specifically. The values of compost teas would be different in gardening because you are likely to save the original compost that was used to brew the tea and put it back into the beds. While this is a worthwhile practice in gardening (especially for people who have too much time on their hands and need an outlet), the total agronomic value of the addition of compost teas has not show to be a worthwhile endeavor for turf.

Now, I’m not saying that there isn’t a time and a place that this might “do something” (aside from giving you a sense of ecological superiority over your neighbor or competitor). We simply haven’t seen enough of an effect for it to truly make sense for a service company. Stay with me here. The reason that this is not a super effective tool for turf is that the carbon stays behind in the “tea bag” and doesn’t make it to the soil. That’s not cool at all. You see, the microbes that come from the brewing process are the same ones that would be feeding on the leaf litter (used for the tea) if it was mulched and left on the soil anyway. So… you create a big populous of these little bugs and then throw their food out (with the tea bag) and throw them onto an area that didn’t have enough carbon to support their life in the first place and you get a whole lot of nothing.

So what’s the best mode here? In the soil, more surfaces created through either fracturing or breaking tight soil bonds, increasing rooting, or increasing carbon content, will give you a much better response to any applied minerals or fertilizers. Surfaces (surface area) and carbon (roots, clipping, leaves, etc.) are the keys to efficient nutrient availability and cycling, aerobic activity, and plant available water.  Simply put; more surfaces + more carbon = better nutrient utilization and better lawns.

The same can be looked at from a macro view.  A lawn is an eco-system unto itself.  Everything on, above, and below the surface plays a vital role in that eco-system. Everything that we recycle within the eco-system reduces what we need to add to sustain it.  If we crush, crumble, shred, or otherwise dismantle leaf tissue into smaller pieces and redistribute them across the lawn, we will get a viable food source that doesn’t suffocate the plant or soil. Smaller pieces of anything are easier to digest, that’s why we have teeth after all…. So in this case, give the grass a good leaf-chipping this fall and see what happens. Where possible, let’s leave the leafs where they lay… your grass will thank you.