Glyphosate and seed

Discussion in 'Turf Renovation' started by RigglePLC, Jan 7, 2019.

  1. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    I am planning to do a test. Seed planted 3, 2, and one day after glyphosate treatment. Will probably also apply seed the same day, glyphosate sprayed directly on top of seed. Probably, will also determine if glyphosate affects seed if sprayed one or two days after seeding. Indoor test in paper cups, with perennial ryegrass. Results in about 7 to 10 days.
     
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  2. Hineline

    Hineline LawnSite Senior Member
    Messages: 869

    I've soaked seed in Gly as an experiment and also sprayed yards with gly the same day as doing the seeding. Seed germs and grows. Sometimes you will spray a yard with gly to prep for a new yard and come back and find bent or weeds re-emerging the day you are seeding. No fear!
     
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  3. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    Good point, Hineline. Seed planting and glyphosate spraying day is Thursday January 10th. It still feels strange to apply a herbicide on top of new seed. Results in about a week. Hopefully some good photographs. Of course--indoor conditions are not exactly the same. I am watering with rain water and using native soil (not sterilized), so weed seeds may occur. The temperature is about 68. There is very little sunlight--but I do not expect sunlight to be an important factor in the breakdown of glyphosate.
    I am throwing the seed on top of the soil with no attempt to incorporate it nor bury the seed.
    Perhaps I should bury the seed a quarter-inch deep in one of the cups.

    I am running out of ideas to test in the winter. No weeds--but I have some Mini-clover seeds that I can use as weeds. Tomato seeds work fine for herbicide tests, also.

    Ha. Ha! I am also waiting for snow. I want to sow grass seed on top of snow for the 2018 version of dormant seeding. Very unusual to have no snow at this time. Snow expected tomorrow.
     
    Last edited: Jan 8, 2019
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  4. Hineline

    Hineline LawnSite Senior Member
    Messages: 869

    One lawn I did was renovated from invasive bentgrass. It was an early seeding with colder soil temps. One day about a week after seeding and still no germination I found plenty of bentgrass in a more shady area that had still not completely turned brown so I sprayed roundup yet again. Seed started germinating a few days later and the bent eventually was completely dead.
     
  5. Eric502

    Eric502 LawnSite Senior Member
    Male, from Kentucky
    Messages: 755

    I'll be watching this. Good idea for an experiment.
     
  6. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    So far the untreated control, perennial ryegrass, is 1.5 inches tall at the highest. This is after 7 days indoors at 68 degrees.
    Glyphosate-sprayed 5 inch tall grass, which serves as a check on the effectiveness of the gly solution--is collapsing and dying slowly, after 3 days.
     
  7. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    So far, after 8 days, the perennial rye seed planted 5 days after glyphosate treatment is doing fine--maximum height is about 2.75 inches. Untreated control is about 4.75 inches tall, as a maximum. Indoors, on native soil, at 68 degrees.
    Hopefully, there will be more results and photos later.
     
  8. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    So far the perennial ryegrass sowed on bare soil five days after glyphosate treatment (labeled -5), is growing the best, but germination was about 40 percent. This as compared to 80 percent germination of the Untreated Control. When the seed was sown at 4,3,2 and 1 day after glyphosate treatment germination was near zero with some sprouts appearing distorted.

    SA400013.JPG
     
  9. RigglePLC

    RigglePLC LawnSite Fanatic
    Messages: 15,359

    Under the above conditions, it is clear that seed can sown about 5 days after glyphosate treatment to bare soil. Even after the 5 days waiting period, the germination was 60 percent.
    Glyphosate applied after seeding prevented most seed from germinating.
     
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