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- When Should I Apply a Lawn Weed Killer?
I just read your answer to Annette's question in Friday's 'InsideOut.' Is is too late then to apply just a lawn weed killer at this time? I was hoping I can do that, and then weed and feed a little later in the spring season. That way could I get better control of the huge amount of weeds I have? If possible, can you do an article on the best times (and temperatures) throughout the year to apply lawn weed killers alone, weed and feed, whether each type should be watered in or not, and the amount of time necessary to wait between applications? I love your column and have learned a lot about gardening from my dad and from you. Thank you!
- Stacey G.
It is not too late to apply a lawn weed killer – although applying it earlier in February would have been much more effective. If you do apply a lawn weed killer now, however, you would just apply a lawn fertilizer (no weed killer) in the next week or two, not a weed and feed.
There is no set schedule to weed control. It depends on your lawn and weed issues. Weed control is done anytime you begin to notice that weeds are becoming an issue – whatever time of the year that is. The weeds in your lawn now became noticeable back in January and certainly by February. That was the time to apply weed killers. If you tend to have problems with summer weeds, herbicide applications in April and/or May will help with that. During the summer when it is hot, you can spray patches of weeds (spot treat) with lawn weed killers if needed. During fall, winter and spring, when temperatures are milder, you can spray the whole yard with weed killers, when needed.
If you want to use preemergence herbicides (click here for examples) to prevent weed issues, apply them the last week of September/first week of October to control cool season weed seeds and the last week of February/first week of March for summer weeds. These weed preventers are applied before you see the weeds.
Here’s a link to the LSU AgCenter lawn care publication with detailed information on lawn care, including weed control: Louisiana Lawns BMPs.
Dan Gill
Consumer Horticulture Specialist