Wondering about Gypsum

Discussion in 'Soils, Fertilizers and Composting' started by C.Dragonworks, Nov 15, 2006.

  1. C.Dragonworks

    C.Dragonworks Active Member

    Messages:
    30
    Likes Received:
    0
    Location:
    S.TEXAS USA
    OK I have a new house we built and the soil is a black clay...hard and cracked when dry mushy and slick when wet... I bought Gypsum to add to the soil but nowhere can I find a suggestion of amounts that will work.... And another thing I read was using limestone as well... I do know I need the Lime but not for that... we use it here on the grass! So how much gypsum do I need to add to make my flower beds and yard soil better... I plan to add organics to the beds! Cat
     
  2. Ron B

    Ron B Paragon of Plants 10 Years

    Messages:
    20,941
    Likes Received:
    654
    Location:
    WA USA (Z8)
    Sample your soil and have it tested.
     
  3. angilbas

    angilbas Active Member

    Messages:
    41
    Likes Received:
    1
    Location:
    Sidney, BC
    Dragonworks, your soil reads like a Vertisol. Gypsum may help if the soil is sodium-rich; otherwise ... most Texas Vertisols have oodles of calcium and any calcium carrier such as gypsum or limestone will be redundant.

    To get details such as sodium content and nutrient availability, you'll need to send a soil sample to a lab. But you can get some idea of your soil's chemical properties at home ... add vinegar or hydrochloric acid (often sold as lime remover) to a sample; if it fizzes, free carbonate is present and the pH is likely to be 8.0 or higher. Another home test involves putting a soil crumb in a plastic glass or petri dish of distilled or deionized water to see if the clay disperses (and discolors) the water ... if so, the clay may be sodic. See this Physical Soil Testing page for more information.


    -Tony
     
  4. gardenlen

    gardenlen Member

    Messages:
    8
    Likes Received:
    0
    Location:
    north brissy s/e qld australia
    g'day cat,

    gypsum is pretty much a soil conditioner for breaking down heavy clay (there are clays it won't work on but most of us have workable clays), it is pretty much neutral ie.,. it doesn't change the ph, and when i use it i use heaps of it and have done for yonks now.

    i buy the good qulaity stuff from the produce agency the best quality resembles damp talcum powder.

    len
     
  5. Durgan

    Durgan Contributor 10 Years

    Messages:
    2,669
    Likes Received:
    100
    Location:
    Brantford,Ontario, Canada
    http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=13781

    The thread indicates the soil conditioning procedure for an addition to the main vegetable bed.

    Have a look at this tread. I have heavy clay almost good enough to make brick blocks for building. At first on the main garden I tried mixing sand which was a disaster since I ended up with cement. When watering all I had was a pond.

    Later I worked in about 30 yards of compost, which I dragged in a half yard at a time. This was 60 trips and about 240 wheelbarrels full. This I did over about three years. Since wood chips were available from the city in a local park, I applied a few yards to make the drainage better.

    The final analysis is that the compost is the main ingredient for conditioning the clay about 40% at a guess. The wood chips improve drainage and resist compacting to some degree. I ended up with a friable bed, and water sinks down into the soil without puddling.

    Conditioning a small bed is relatively easy, and not too expensive if you have to buy the compost and wood chips. If the bed is raised, a foot or so, drainage will be much improved.

    Durgan.
     
  6. chuckrkc

    chuckrkc Active Member

    Messages:
    130
    Likes Received:
    0
    Location:
    Kansas City, Mo.
    I think the best route is to create a raised bed and fill it with material much like Durgan used.

    With sand, you would have to add an astounding amount (like 85%, according to an agronomist's lecture at the Western Nursery & Landscape Assn Show in January) to change the soil structure. "Like cement" is right if it is less (or what I would have thought before was a "reasonable" amount).

    On gypsum, from K-State Extension:

    "A popular misconception is that gypsum (calcium sulfate) will improve clay soils by making them more friable and increasing water infiltration. Research has shown that gypsum will not have an effect on either of these qualities unless the soil contains excess amounts of exchangeable sodium (a sodic soil). Sodic soils have extremely high pH readings – above 8.5 to as high as 10. In most areas, sodic soils are rare.

    "The sodium in a sodic soil has caused the internal structure of the soil to collapse, thereby reducing water infiltration rates and friability. The calcium in gypsum will replace some of the sodium and allow structure to reform. The soil should be kept moist to allow the gypsum to work and then leached with irrigation water (unless you have plenty of rainfall) to wash out the sodium."
     
  7. gardenlen

    gardenlen Member

    Messages:
    8
    Likes Received:
    0
    Location:
    north brissy s/e qld australia
    your welcome to check out how we do our raised beds, curently have just finished another bed.

    all with pic's and descriptions.

    see our link below.
     
  8. Gardenlover

    Gardenlover Active Member

    Messages:
    309
    Likes Received:
    0
    Location:
    Southern Ontario, Canada Zone 6a
    According to this gypsum is useless for improving drainage in neutral soils. It works for sodic soils.
     
  9. Ron B

    Ron B Paragon of Plants 10 Years

    Messages:
    20,941
    Likes Received:
    654
    Location:
    WA USA (Z8)
    Yes, it flocculates alkaline clays only.
     

Share This Page