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hgintoft

Sand? Vermiculite?

12 years ago

Last year I put in my first raised garden beds. We moved in the fall and brought them with us. Last year my pepper, eggplants and root vegetables (carrots, parsnips, beets) did poorly. I'm thinking my beds may need better drainage. My initial mix included topsoil (bagged), compost from multiple sources, a bag of vermiculite split over 2 4x8 beds and peat moss. My neighbor had an in ground garden and her pepper plants did AMAZING! I noticed the area had very sandy soil so I'm wondering if that's what I need.

Also, does anyone use a mulch on top of their raised beds? If so, which kind? I tried cocoa husk and it seemed to attract bugs like crazy so I removed it.

Comments (7)

  • 12 years ago

    Is the raised bed open to the ground below or is it on concrete or raised off the ground?

    what kind of bugs did the husk attract? Some bugs, like spider, are good.

  • 12 years ago

    Open to the ground (which I dug up prior to putting the beds down). It was on top of the super sandy soil I mentioned.

    The bugs were some sort of beetle in MASSIVE quantities. They laid their eggs in the soil and their larve were everywhere in my soil. As soon as I got rid of the mulch and used an organic powder, they were gone. Only had normal insect population afterwards. Is cedar acceptable? That way it would naturally repel bad bugs, but help retain the moisture.

  • 12 years ago

    The most important factor is that your neighbor 's garden was in the ground. Raised beds have become foolishly popular these days but artificial concoctions are rarely an improvement over native soil systems.

    One cannot add sand in order to improve a crappy situation. Naturally sandy soils are a blessing. Vermiculite cannot improve porosity....it collapses and turns to mush when exposed to moisture.

    I strongly suggest that you get some help evaluating your native garden soil and natural drainage. Your gardening experience could be much more successful if you have halfway decent native soil.

  • 12 years ago

    Soil is composed of the mineral portion (the sand, silt, and clay particles) and organic matter. Sand, the largest of the mineral particles, helps promote drainage since the pore spaces between the sand particles are quite large. The silt (smaller than sand but larger than clay) and clay (the smallest and most uniform) particles, smaller in size, help fill in between the sand particles but the organic matter does that even better and helps hold both nutrients and moisture as well.
    Vermiculite and perlite are minerals that function in the same way that sand would and in a raised bed would be an expensive substitute for the sand portion of a soil mix.
    A good soil mix would be loam, a soil mix that has a known definition, unlike "topsoil" which is simply the top 4 to 6 inches of soil from someplace.
    Your problem last summer may well have been that the Soil Food Web, the wee buggers in the soil that feed the plants, were simply not able to function in that newly mixed soil.

    Here is a link that might be useful: What is loam

  • 12 years ago

    I would do a soil structure test with a mason jar on the native soil. It sounds like you will be fine by just mixing the soil and all that organic matter you put in the raised bed thouroughly.

    Also, get a soil test.

  • 12 years ago

    Along with a good reliable soil test for soil pH and major nutrient levels perhaps these simple soil tests might be of some help.
    1) Soil test for organic matter. 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. For example, 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 drainsâ 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 your 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.

  • 12 years ago

    Second the advice on a soil test. A number of things could be out of whack - pH (if compost was manure based from a horse barn, for example), N deficient (if any organic matter added was N deficient), persistent herbicides (again from manure compost).