When to apply Gypsum

Discussion in 'Pesticide & Herbicide Application' started by The Rookie, Nov 30, 2006.

  1. The Rookie

    The Rookie LawnSite Senior Member
    Posts: 296

    I was told that applying gypsum to turf could aid in releiving soil compaction. Is this true? How much gypsum does one put on 5000 sq ft.? Where can a person get it? What is it? Any information appreciated.
  2. lilmarvin4064

    lilmarvin4064 LawnSite Senior Member
    Posts: 757

    Not every lawn will benefit from gypsum (calcium sulfate). You need to do a soil test to see if your lawn really needs it. Worry about the lime first. If your pH is good, and your lawn is still low in calcium and high in magnesium, then adding gypsum would be beneficial. Suface applications won't do a whole lot, so apply it at when core aerating or tilling; 40 to 50 lbs./ 1000.
  3. muddstopper

    muddstopper LawnSite Silver Member
    Posts: 2,342

    You apply gypsum when your base saturation levels of calcium are low, magnesium is high and sulfur is low. Never use gypsum just because someone says it will loosen up your soil. It can and will loosen up the soil in the right conditions, but it can also make the soil very, very hard if used under the wrong conditions. The calcium in the gypsum is what loosens up the soil. Get a soil test, its the only way to know for sure if you need gypsum or whether you just need plain old lime.
  4. upidstay

    upidstay LawnSite Bronze Member
    from CT
    Posts: 1,348

    If you are trying to alleviate compaxction, then aerate. Use a solid tine for rock hard soil, and follow it up with core aeration. Aer-Away makes a soil shatterer that is great. Follow aeration up with a sand and/or compost top dressing. Then aerate once or twice a year after that. Keep soil pH right and nature will take care of it for you.
  5. muddstopper

    muddstopper LawnSite Silver Member
    Posts: 2,342

    Another myth is using sand to loosen up the soil. In order for sand to help with areaton you would have to mix the soil and sand 50/50. This means if you are trying to fix the aerobic zone, which is about 6 3/4 inches of the ground, you would have to add 1 million lbs of sand per acre AND TILL IT IN!. A little sand and clay soil equals concrete. If you get your base saturations of ca. mg, K, and na correct, the physical condition of yor soil will improve which will also improve the aerobic zone, which will also improve the microbial life. And its a lot cheaper than 1 million lbs of sand.
    Get a soil test and do the job right the first time.

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