Question
Hi there! I have been noticing a lot of hoopla about people pouring sugar on their grass. Does this do something like give them carbohydrates or something? Why do we need beneficial organisms? Just wondering. You sometimes have a different take on things. It seems to me they would only get all the ants and roaches in the neighborhood to migrate closer to my house.

Answer
people who add sugar to their lawns completely misunderstand how plants feed and what exactly microbes are good for. The hype is no doubt due to a book by Jerry Baker who has taken sound principles of organic gardening but has ventured into a theory which has a great following but for which there is very little scientify support or proof. IMHO it is a little like an astronomer becoming an fortune teller using star signs.

How plants feed
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Plants make their own food stuffs, in fact, they are the first link the food chain and synthesize proteins and carbohydrates from some key basic biological elements (such as nitrogen, phosphorous, and potassium) and using the sun's rays as energy source, they create plant energy (carbohydrates).

Engery which is not consumed by the plants immediately for growth is stored as fructose or as starches. I.e. sugar is just one such example of carbohydrates (stored energy) which a plant (either sugar cane or sugar beets) have stored temporarily. Humans or animals have then harvested the sugar and can eat it as energy (we can not synthesize our own energy - we need to eat energy already produced by plants or animals for energy).

Plants can not take up already made energy (such as sugar). They must produce their own. To do this they need fertilizer which contain the building materials needed to produce their own energy. Therefore, putting sugar on the lawn does not give energy to the grass (although sugar, being a carbohydrate, is energy). Grass must produce its own energy from fertilizer nutrients.


How mircobes grow
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The microbes in soil break down dead matter, including "spoiled" energy such as sugar, and convert it. Some of the mircobes die or are eaten by other microbes and the waste product is a term we commonly refer to as "organic matter". Organic Matter (OM) is beneficial for soil because it creates small spaces between the soil particles where plant roots can grow and it helps regulate water and nutrient distribution within the soil.

Generally, a lawn with good organic matter content will have good conditions for grass plant growth.

However, microbes do not require sugar to grow. They feed on partially decomposed materials, such as grass clippings or shredded leaves. Therefore, if you recycle grass clippings (use a mulching mower) you can get a good biologically sound soil.

If your soil is very deficient of organic matter, then adding a layer of compost a few times per year can be beneficial to build up the soil over a period of years, but typically most home gardening soils are fine as grass can grow over a wide range of soils.

Adding sugars do really nothing for the soil that regular lawn care maintenance could not. Adding sugar may temporarily boost the amount of microbes in the soil (they will populate explosively when enough food is available to eat) but once the food supply becomes in short supply again, most will die out again. This rapid fluctuation in mircobe population in natural. Adding sugar does nothing more than boost the microbes for a few days until the sugar has been consumed and then they due back again. You might as well mow the lawn; it has same effect.

The most important you can do for your lawn, is to mow it frequently and at the correct height and then fertilize your lawn at the right times using the right amount of fertilizer. This will ensure a healthy, well growing lawn.

Just because a soil contain temporarily a high amount of mircobes, it does not make it a good soil. The microbes need complex materials with complex molecules to break down in order to "leave" something after they eat, and to create OM (which eventually becomes Humus in it's final stages). However, sugar is a very simple carbohydrate which leaves virtually nothing after being consumed.


I.e:
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Sugar is not lawn fertilizer. Fertilizer must contain nitrogen, phosphorous, potassium plus a range of other nutrients required in smaller doses. Sugar contain none of these.

Sugar can help boost the microbes in the soil, but for what ? The sugar does not leave any noticable OM left for the benefit of the soil. However, nitrogen mixed with carbonrich products do. Therefore, compost is beneficial as top dressing, and so is mulching the fallen leaves from trees into the grass (with moderation) aided by a layer of synthetic quick release fertilizer in the fall. Mowing the lawn is much more beneficial to the lanw than a layer of sugar.

Therfore, if you have the choice between a man-made synthetic fertilizer derrived from the oil and gas industry or a bag of sugar: go for the fertilizer.

It is that simple.

-- Kenneth