Knowledgebase
weeds and grass in garden #862727
Asked March 28, 2024, 1:10 PM EDT
My husband put horse manure in our garden. Unfortunately now it is infected with weeds and grass. I've been pulling it for the past 2 years, but I just can't seem to get a handle on it. What can I spray the weeds with and still plant a vegatable garden?
Denver County Colorado
Expert Response
Hi Mary,
Thanks for reaching out to us about the weed problem in your vegetable garden.
There are a myriad of free online gardening resources available to the public that are based upon research from US university horticulture departments. One such resource is Fact Sheet #2018 Vegetable Garden Weed Management
The author Dr. Koski states that gardeners can “Kill emerging weed seedlings with synthetic or “natural” herbicides or kill emerging weed seedlings by flaming”. Herbicides one can use can be either “Synthetic” (like Glyphosate or Trifluralin) or “Natural / Organic” (like Corn gluten meal). Please read the container’s instructions carefully before applying.
Another resource that might be useful is Garden Note #242 on using manure in gardens (in case someone is ever tempted to use manure in the future). https://cmg.extension.colostate.edu/Gardennotes/242.pdf
The article warns some “disadvantages of farm manure include: Potential burning of roots and foliage from high ammonia. Potential residual herbicide damage to crops. High potential for weed seeds… Horse manure is legendary in its potential to introduce a major weed seed problem into a garden. Composting the manure before application may kill the weed seeds if the pile heats to above 145ºF and the pile is turned to heat process the entire product.”
Enjoy your garden!
