Expanded Shale

[Blowmonkey 79]

Wel iets grappigs tegengekomen op internet de laatste weken. Expanded shale. Geen idee hoe het in het Nederlands zou moeten heten.. Lijkt een ideaal product, misschien is het allang bekend hier, maar kon niks vinden met de zoekmachine.

 

Zal wel een paar stukkies info plaatsen, in het engels:

 

Expanded shale is like "Vermiculite plus"--it is, as I understand it, "popcorned" shale rock.

 

Please realize that vermiculite is expanded, or "popcorned", mica. Mica is naturally a rock made of many fine layers--all fragile and glassy (silica rock is, basically, glass--so you have whisper-thin layers of glass puffed out, mostly apart). When expanded, mica forms a very fragile accordian shape that holds a lot of moisture--and usually some air. The air is needed to keep roots from drowning--they have to breathe, too! Alas, mica breaks down quickly into tiny blobs that can form a gray mass of blech -- say, if used at the bottom of a container. Even if the blobs are evenly distributed in your dirt-free soil mix, they still won't hold air anymore--and don't hold much water. Blobby mica is not a sterling aid to roots anymore. Solution? Add more vermiculite (at an annual cost), try another product/substance/method, or move to expanded shale.

 

Unlike mica (which expands into a fragile accordian shape to make vermiculite), shale starts as a roundish rock. Expanded shale retains a smooth rocky appearance--just larger. (Think of corn expanding into hominy--still a distinct shape, but bulkier.)

 

What is so wonderful about expanded shale? Expanded shale *always* retains 30% air. Even if you dump it into a bucket of water, the stuff still retains 30% air (in normal environmental conditions). This means your plants'

roots always have access to air, so they are pretty much drown-proofed. Texas A&M tested solid clay soil, in a ground-level bed, with moisture-sensitive plants. Solid clay soil slew the poor test plants rapidly (as anyone with clay soil already knew.....) The plants in the bed with expanded shale survived and *thrived*--that 30% air pocket content saved them. Naturally, the 70% water pocket content provides needed moisture to plants, even in challenging conditions like raised beds/containers in 110+ degree F summers. (Probably great for vacation survival for houseplants, too. Also for people with "blue thumbs" who overwater everything....)

 

Expanded shale is easy to use. It is useless to put a layer of expanded shale in the bottom of a container--just mix it evenly in the soil. The A&M experiment was 50% clay, 50% expanded shale. Your good compost/coir (or peat, or varied, aged compost only) soil mix will not need that much shale.

 

Unlike the water absorbing gels, expanded shale will never swell or shrink, so you don't have to worry about the soil (and plants) heaving up or collapsing.

 

I got mine at a fine plant nursery in Dallas, Texas called Northhaven Gardens. The brand name is TruGro Soil Conditioner.

 

Expanded shale weighs more like lava rock than vermiculite--and has the same ability as lava rock to remain intact for many years (centuries? millenia?) at a moderate initial investment.

 

Can you introduce expanded shale into your squarefooting program gradually (and spread the initial cost of 8-10 U.S. dollars for a bag the size of a large sack of compost/hummus/soil)? Yes. I think you could gradually mix expanded shale into your squares along with your new scoop of compost, each time you replant. An end result of 25-33 % expanded shale should be very beneficial to your squarefoot beds or containers, whether raised or in ground. I'm sure that even 1-15% would give a definite benefit to most gardens.

 

Expanded Shale - A new Possibility for Amending Clay Soils

 

by Dr. Douglas F. Welsh, Professor & Landscape Horticulturist, Texas A&M University

A form of expanded shale is now available to gardeners that will be useful in loosening tight clay soils and making them more workable.

 

'Blue Shale' from the Midway Shale formation is present in a pattern across Texas through Corsicana to Texarkana and stopping near Laredo. It is usually found 10-15 feet underground. It was formed during Cretaceous times when Texas was a large lakebed and the lakebed sediments solidified under pressure into the present-day shale formation.

 

Jack Sinclair of TXI Industries has explained that the shale is mined and ground to 1" to l/2" range particles and then kiln fired. As it progresses through the kiln for 40 minutes at 2,000 degrees C, certain chemical processes take place in the silica content (60-70%) causing the material to expand. The expansion of Kitty Litter (calcined clay), for example, occurs at only 800-900 degrees.

 

As the material cools, cavities are left after gases escape, leaving a porous lightweight chunk capable of absorbing water and releasing it slowly at a later time.

 

Recommendations for using expanded shale with containerized plants call for putting one-third of the material in the bottom, then mixing the expanded shale with potting soil 50-50 for the rest of the pot.

 

For flower beds with sticky or gumbo-type soil, Dr. Steve George of the Texas Cooperative Extension recommends putting down 3 inches of expanded shale on top of the area, and tilling it in six to eight inches deep. Also add 3 inches of finished, plant-based compost as well, which results in a 6-inch raised bed. Crown the bed to further improve water drainage.

 

Dr. George also remarked:

 

"Based on a two-year research study and six years of field trials, I feel that expanded shale will open up and aerate heavy, sticky clay soils faster than any material that I have ever tested. Due to its porous nature, it provides aeration from within the shale particles and, in poorly aerated clay soils, resulted in a more extensive and healthier root system than did other treatments being tested....Even though I dearly love finished, plant-based compost, if I were limited to only one application of one soil amendment with which to open up heavy clay soils, I would take expanded shale and never look back!"

 

Several trials are underway at the present time to test the long-term effects of using expanded shale. Last June Dr. Frank Allen and the city of Duncanville laid out perennial flower beds in black gumbo and the city of Carrolton (situated on Blackland Prairie soils) is working on field trials with Dr. Steve George. Trials include working with black gumbo only, lava sand with gumbo, compost with Blackland soil, and compost and expanded shale in existing soil. It is anticipated that the lightweight material might create a permanent physical change in the blackland soil (or, according to Dr. George, last at least 10 years as a conservative estimate).

The amendment is now sold by the TXI Corporation under the brand name 'Tru-Grow.' It may be purchased in the Dallas/Fort Worth, Houston, and Navasota areas. Check with local garden centers and suppliers for availability in your area.

http://aggie-horticulture.tamu.edu/extensi.../Expdshale.html

 

The Use of Expanded Shale in Landscape Mixes

 

Homeowners frequently use organic landscape mixes to improve physical and chemical properties of their gardens and planting beds. The objective of this study was to determine if inclusion of inorganic expanded shale in the mixes would improve their performance.

Four basic organic landscape mixes were prepared using traditional and alternative organic materials: 1) 75% pine bark + 25% sphagnum peat moss, 2) 50% pine bark + 50% wastewater biosolids, 3) 100% municipal yard waste compost, and 4) 65% pine bark + 35% cottonseed hulls. Expanded shale was blended with each of these mixtures at rates of 0, 15, 30, and 60% (v/v). Three sets of pots were planted with Vinca (Catharanthus roseus), Verbena (Verbena hybrida), and Shantung Maples (Acer truncatum).

 

Plant growth was monitored for several months followed by harvest of Vinca and Verbena plants to determine total biomass yield. Vinca plant tissue was chemically analyzed to assess how the landscape mixes affected nutrient and heavy metal uptake. Vinca, grew best in the compost mixture and its performance was improved by blending up to 30% expanded shale into the mixture.

 

Both the perennial flower, Verbena, and the woody ornamental, Shantung Maple, grew best in the 50% pine bark + 50% biosolids mixture, followed closely by the 75% pine bark + 25% sphagnum peat moss mix and the 100% compost mix. For all three species evaluated, plant growth in the 100% compost mix was improved by the addition of 15 and 30% expanded shale, but plant growth in the 75% pine bark + 25% sphagnum peat moss mix and the 50% pine bark + 50% biosolids mix was diminished by including expanded shale in the mix.

 

Expanded shale increased the uptake Ca and Mg by Vinca, but decreased the uptake of phosphorus. Decreased P and trace metal uptake was probably due adsorption by the high pH expanded shale. Expanded shale can improve the performance of landscape mixes that primarily contain decomposed or composted organic materials. The increased performance is probably due to an improved porosity in the mixtures.

http://www.ashs.org/index.php?option=com_c...&Itemid=145

 

Meer info is welkom, vooral waar het verkrijgbaar zou kunnen zijn.

[Blowmonkey 79]

Misschien dat een move naar algemeen meer reacties/discussie oplevert? Beetje dood tot nu toe.

[Blowmonkey 79]

BUMP.

 

Niemand ooit iets van gehoord? Kan me haast niet voorstellen..

[lovit 0]

denk dat het teveel leeswerk is hahaha allemaal stoners hahaha als ze de ene regel hebben gelezen.zijn ze em alweer vergeten haha

 

groetjes

[Bruut 2]

waar is het verkrijgbaar=

[Blowmonkey 79]

Product naam is "TruGro Soil Conditioner", alleen overzees verkrijgbaar zover ik weet.