Molasses for Weed Plants: What Does Science Say?

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What Happens When Carbohydrates are Applied to Soil?

Yakov Kuzyakov investigated glucose uptake by maize roots and its transformations in the rhizosphere. When glucose is injected into a growing medium containing a live maize plant, 30 % of the sugar is respired and converted to carbon dioxide and water within 96 hours. An identical growing medium without any plant present only had 15 % of its Glucose respired within the same time frame, so about half of the respired sugar was processed directly by the rhizosphere. [1]

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Can Plants Use Their Roots to Absorb Carbohydrates?

The simple answer is yes, but it’s not that simple. Plants do have glucose transporters on their roots. In a sterile system, it’s relatively simple for a plant to take external sugars through its roots. Things change once the roots need to compete with the rhizosphere, a wall of hungry bacteria separating the roots from the Glucose added to the soil. The discussion segment of Yaakov’s report mentioned that the maize roots failed to compete against the rhizosphere to uptake glucose.

Use Carbohydrates to Supercharge Root Microbes.

Roots cells are leaky, continuously excreting carbon in the form of sugars 3.1%, sugar alcohols 3.8%, amino acids 10% and 18% phenolic compounds; I have not found the composition of the remaining 65% [2]. These root extrudates encourage the growth of a rhizosphere, a herd of microbes 100 times denser than the population of microbes in the bulk soil. Supplementing more sugars to the growing medium will no doubt boost the microbial population.

Reports of Carbohydrate Supplementation

I couldn’t find many studies focusing on how carbohydrate supplements can be used as biostimulants. However, I did find a few resources. First, let me start with the “CANNA BOOST ACCELERATOR” test report. The product was used on tomatoes and compared against a control and other commercial “boosters”. CANNA’s carbohydrate supplement performed the best, increasing yields by 20 per cent compared to controls.

How Do You Use Carbohydrate Supplements

Firstly, you need to know your options. The simplest come in the form of carbohydrates which are compatible with hydroponic systems. All you need to do is dilute as per the instructions and then top feed. I recommend using carbohydrates for each watering event throughout the entire grow water without nutrients in hydroponic systems.


  1. Glucose uptake by maize roots and its transformation in the soil rhizosphere. By Y. Kuzgakov and others. Published in Soil and Biochemistry in 2006.
  2. Sugars en route to the roots. Transport, metabolism and storage within plant roots and towards microorganisms in the rhizosphere. By N. Hennion and others. Published in physiologia planturum in 2018.
  3. Plant and soil relationships between fungi. Published in the international journal of research studies in bioscience in 2014.
  5. Soil injections of carbohydrates improve fine root growth of urban trees. By G. Percival. Published in the Arboricultural journal in 2004



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Jason Maverick

Jason Maverick

Autistic and Opinionated | Instagram: Jason_d_maverick