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Organic Answers Column - August 3, 2022

Nutgrass problems? Control it with Liquid Molasses


Nutsedge Cyperus esculentus or Cyperus rotundus


Nutsedge or nutgrass (not a grass and it has no nut) is a persistent weed that happily spreads through gardens and turf and is difficult to kill. Instead of chemicals, killing it with love seems to work. Pouring liquid molasses into your watering can instead of orange oil or vinegar does the trick. Here's how.


Use liquid horticultural molasses 


Drench problem spots with liquid horticultural molasses at ¼ to ½ cup per gallon of water. Start with about a gallon of drench per every 9-10 square feet. This simple technique fires up the microbes in the soil and the nutgrass simply fades away. It takes a while to work and requires at least 2 - 3 applications. As opposed to toxic chemicals, it makes the soil heathier with every application.


It may take 2 or 3 treatments



You can spot spray with the Avenger product to speed up the process if turf and other good plants can be avoided. (Avenger is a broad spectrum herbicide that will kill everything.) Physically removing the damaged weeds obviously also speeds up the process.


Read more about Nutgrass


And finally here’s an interesting report on using this technique.


You suggested that we use molasses to stop nutgrass. We tried it and it did not kill the nut grass. Thought I had made a mistake until I dug it up and low and behold — NO NUTS in the nutgrass. The molasses stopped the development of the nodes that stay in the ground when you pull up the plants. It worked! Just thought I would pass that discovery on! M.A., Rowlett


Thanks very much for the report. That explains why it takes more than one application of the molasses to kill the tops.


Beyond the use of molasses or chemicals, or in addition to, there are also some tools ideally suited to removing nutsedge if it has established itself in the good soil of a garden or if it is growing in sand or pea gravel. Try the stirrup hoe. Discussed in several Dirt Doctor topics here to do with hand tools, the stirrup hoe is ideally suited to pull the nutsedge free of the garden or gravel without digging. It is also called the "push pull" hoe.


Stirrup hoe






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