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dtownjbrown_gw

Determining Drainage & Soil Composition

18 years ago

Im new to gardening and am trying to determine how well my soil drains. I read somewhere that drainage could be "tested" by digging a hole 12 inches deep & 12inches wide. Then filling it with water twice (once to get the sides wet and a second time to test the drainage). Lastly, after a 24 hours has passed, you're supposed to check to see how much water is left.

I did this yesterday and while I was digging I encountered very thick and sticky reddish-toned soil (that I believe to be clay). After the 24hours was up, I was shocked to find that all the water was gone (I thought clay held onto to water for a long time). Although the bottom of the hole was gooey...or should I say sludgy....there was definitely no water left.

Im planning on doing this again tomorrow and "timing" it to see exactly how long it takes for the water to disappear, but I was wondering if anyone had an idea of what type of drainage I might be dealing with (based on my description so far)?

Thanks :-)

Comments (20)

  • 18 years ago

    I am not sure if this helps (but it couldn't hurt).
    ialbtc

    Here is a link that might be useful: testing soil texture

  • 18 years ago

    You should not have waited 24 hours. Fill the hole you dug with water and wait for that to drain and then fill it again and time how long it takes the water to drain out. I have for years posted 5 simple soil tests people can do to see what their soil is like;
    1) Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top.

    2) Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up.

    3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart.

    4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell.

    5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

  • 18 years ago

    Thank you both for the test suggestions.

    @ ryanzone7 - Im "drying" my soil right now to conduct the texture test your linked in your reply. I had everything except the powdered dish detergent so I went add bought a trial size box of that. Im anxious to see what my sediment layers are.

    @ kimmsr - thank you ever so much for all the test descriptions. I was just about to do your test #1 which is very similar to the test ryanzone7 posted. Im doing your test #2 right now. I filled the hole once already & now Im waiting to see how long it takes the to drain ( not sure if this means anything but it took a little over an hour for the 1st water filling to drain. I think Ive conducted your test #3 before, but I dont believe the soil was damp. I know that once the soil dries, it is hard as a rock....literally. When I first start getting my feet wet, I threw out alot of dirt thinking it was rock. Now I apply hard pressure to it first, to see if its actually dirt. As for your test #5, I know for a fact that there are ZERO earthworms in the soil. I never noticed this before until after I amended the beds in my front yard (which is swimming in them now).

    Thanks again to both of you for your input & advice. I'll be sure to report back when Ive finsihed all the tests. Im sooo excited....isnt gardening fun :-)

  • 18 years ago

    [QUOTE kimmsr: Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top]

    Quick Question: My one quart glass container (an empty jelly jar) is only 5 inches tall.....do I still want to add 4 inches of soil to it?

  • 18 years ago

    @ kimmsr - here are the results from the tests Ive conducted so far. Can you tell me what they mean?

    1) Structure - test still pending

    2) Drainage - it took 3 1/2 hours to drain completely. Would the rate of drainage help with a diagnosis? Just in case it does, I took pics of the level after the first and second hours (see below). The water had gone down 5 inches after the 1st hour and a little over 7 1/2 inches after the 2nd hour.....does that offer any "extra" insight?

    3) Tilth - Im not sure if I did this test right because I couldnt gauge how wet "slightly damp" should be, but Im thinking it may have been too wet because it kept sticking to my fingers to the point of being caked on. Just in case I was doing it wrong, I used my digital camera to record a quick video (see below). So anyway, I squeezed it tightly and when I released the pressure it formed a very firm clump. When I tried to poke it with my finger it didnt fall apart at all. Instead, my finger just left an indentation in it & the clump flattened a little bit but stayed completely intact.

    4) Smell - In my opnion, the smell was definitely earthy but I wouldnt really call it "pleasant". It wasnt "putrid or offesive" either so Im not really sure what that means.

    5) Life - I think I answered this one already....ZERO EARTHWORMS.

    Thanks for taking the time to review these results for me. xoxo :-)

    VIDEO FOOTAGE OF TILTH TEST
    http://www.youtube.com/watch?v=ibS2r0p3M6s

    LEVEL AFTER ONE HOUR
    {{gwi:299893}}

    {{gwi:299895}}

    LEVEL AFTER TWO HOURS
    {{gwi:299896}}

    {{gwi:299897}}

  • 18 years ago

    At a glance it looks like clay lightly mixed with small rocks.

  • 18 years ago

    That's what I thought too but when I squeezed the "small" rocks between my fingers they broke apart (they're actually hardened soil). I recorded video on that too. Im taking this gardening stuff seriously, huh? LOL :-)

    Here's the link: http://youtube.com/watch?v=t9ihBnSR2PU

  • 18 years ago

    You have a soil that needs a lot of organic matter, because it drains a little too quickly, it does not smell pleasant (I have often told people that soil should smell like that good, rich earth odor that comes in the spring only to now realize many people have never smelled that) it holds together too tightly when slightly damp and there is too little soil life. Each test, by itself ddoes have meaning, kind of, but taken all together they tell you more. Liked with a good, reliable soil test (I am told by some that Ohio State University USDA Cooperative Extension Service does not do these, while others tell me they do) these can aid in correcting your soil problems so you will,eventually have a good, healthy soil.

  • 18 years ago

    So adding organic matter only, helps with the drainage? What about improving the health or increasing LIFE? What type of organic matter would you suggest I add to my excessively drained, non-pleasant smelling, too tightly held together, lifeless soil? (I hope I got all the test results in there :-))

    When I amended one of the firsts bed in my front yard, I used 100% compost & manure but I didnt mix it in, I actually took out 6 inches of soil from the top then replaced it with bags upon bags upon bags of store bought compost/manure mix. This was my first attempt so I didnt realize it could just be tilled into the existing soil. I thought what I had to do was "take out the hard stuff" and "put in the easy stuff". Now that Im doing these tests on the unamended portion of my yard, Im wondering if that was a bad thing to do. Granted, it has significantly increased the LIFE in that area because I'm definitely noticing earthworms now, but replacing it totally with compost wouldnt have done anything for the drainage, structure or composition of that area.....is that correct?

  • 18 years ago

    No matter what type of soil you have, except a boogy soil, adding organic matter will help it. If what you have is clay the OM gets between the clay soil particles, seperating them, so excess water can drain through easier. If you have sandy soil the OM gets into the pore spaces between the sand particles and holds both the moisture and nutrients in place longer so the plant roots are able ti utilize them.
    So adding organic matter, lots of organic matter, will be a help no matter which soil type you do have.

  • 18 years ago

    "No matter what type of soil you have, except a boogy soil, adding organic matter will help it. "

    I'm curious. What's a boogy soil?

  • 18 years ago

    [QUOTE kimmsr - Structure.....make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight.]

    I think I might have to do the Structure test over again. Its been two days and the only layer I can see is the bottom one (sand) which is only about 3/4 of an inch. The next "visible" layer goes all the way to 3 1/2 inches but I cant tell where the silt ends and the clay begins. The rest just looks like cloudy water with bits of leaves floating on top. So now Im wondering, since I put 4 inches of soil in the jar, where did the other 1/2 inch go?

    The link provided by ryanzone7 had an "extra" instruction step that called for adding dish detergent to the jar, but I didnt do that part....should I have?

  • 18 years ago

    Adding detergent, a surfactant, is unnecessary. It sounds like you have about 18 percent sand and about 87 percent clay. Since there is no seperation there will be no silt, unless what you do have is silt and not clay. The other 1/2 inch could be air and the cloudy water is normal. Since mostly what you want to know with this test is the amount of organic matter you can see that and what you have is way too little, very common today in soils all over the USA.

  • 18 years ago

    So if what Im seeing is silt (and not clay) the remedy would be to add organinc matter? If its clay (and not silt) the remedy is still add organic matter?

  • 18 years ago

    The remedy to improve any soil is always add more organic matter unless you have boggy soil (by the time I saw that I had typed boogy before I could not go back and change it). The reason for doing the test to see how much OM you have in your soil is so you know how much you need to add, to see how much you have or do not have. Any gardener should have a good working knowledge of their soil and the only way to know that is to look at it, in depth.

  • 18 years ago

    I should have realized you meant boggy. I googled boogy soil and couldn't find anything, but for some reason, didn't make the connection.

  • 18 years ago

    Kimmsr: Please answer a question on #5. Does the number of earthworms per shovel differ at all depending on the weather? or the time of the year?
    In early spring there are plenty. But now in July I cannot find any. Should I be digging down deeper? into the soil this time of the year? Here in IL it's been extremely moist.
    In June when we set record levels of rainfall, some of the townsfolk have talked about "the smell" outside. They are saying it's the smell of dead earthworms. In all honestly, I can't smell a thing. I'm in a small town surrounded by IL cornfields/soybean fields.
    Thanks for your time.

  • 18 years ago

    I forgot about my jar test so I went to dump it out yesterday and noticed that the level has settled more since I looked at last (by at least an inch). What, if anything, does that mean?

  • 18 years ago

    sudzy, earthworms move around in the soil depending on soil moisture levels, soil temperature, food resources and any number of other factors so you may well see many in the spring and very few in July and August if those factors in your soil vary greatly. In my planting beds, where the soil will stay cool and moist and has a lot of organic matter I can find many earthworms even in July and August, but the lawn may not have any at that time because of the low level of organic matter there which also means the soil is not as moist as they prefer and it is warmer then they prefer.
    dtownjbrown, that simply means more has settled, it is not significant.

  • 18 years ago

    Thank you Kimmser. I thought that perhaps the recent flooding might have killed them off drastically. I check again when it cools down some.