Ella: Yes, same as "sharp sand" or "builder's sand" or "leveling sand" sold at Menards for $2 per bag, and at HomeDepot for $3.49 per bag. It's yellowish, very coarse. Play-sand is sold at Walmart, very fine, thus glue-up with clay.

http://www.wisegeek.com/what-is-sharp-sand.htm

"Sharp sand, also known as builders' sand, refers to sand that has a gritty texture. This type of sand is often mixed with concrete for a number of different construction applications. Sharp sand can also be added to soil in order to create potting soil or to loosen clay soil. In most instances, this type of sand is made from ground quartz rocks. "

Prairie: Thanks for the info., really appreciate the time you e-mailed me the document on rose-breeding and blackspot strains .. that's to de-bunk the myth of Knock-outs with BS resistant-strains just to promote Knock-outs as the ONLY resistant roses. My experience: any vigorous roots would be disease-resistant, it doesn't have to be Knock-outs. I dislike false advertisement like that just to promote knock-outs, selling for $18 per pot, while other just as healthy roses being sold for $8 per pot.

Val: I already answered those questions when you jumped into my thread while Kelly asked about her heavy clay. I shared in detail on how I used 12 bags sand for 24 tomatoes, with 1/2 bag of sand per planting hole, worked to depth of 12 inch, along with gypsum.

I posted extensively about using coarse sand to break up heavy clay, starting in 2012. People falsely accuse SAND making concrete with clay, but people don't realize that THE TAP WATER THEY ARE USING is causing the glue-up. To treat tap-water and to deodorize, municipals use hydrated lime (calcium hydroxide), which is made from quick-lime, both compounds are used in making concrete.

I notice that my Austin roses planted in partial shade, which I never bother to water, are 100% healthy .. versus those planted in full-sun with frequent tap-watering .. came down with blackspots. I dig up roses often in my garden, either moving them around, or they die after a harsh winter.

The holes with frequent tap-water: soil became rock-hard, despite my previous breaking them up with organics like alfalfa hay. pine-bark, or coarse sand. Alkaline tap water at pH near 9 makes concrete out of clay. Hydrated lime is DIFFERENT from natural dolomitic lime. Hydrated lime is UNSTABLE, and it binds with potassium, phosphorus, and trace-elements, thus roses become pale, less blooms, and break out in diseases due to less potassium. and anti-fungal trace elements.

That's why use sulfate of potash plus gypsum to de-activate the gluing-effect of hydrated lime. I sent my observation to Predfern, a rose-grower with Ph.D. in Physical Chemistry, and he sent me scientific studies to back up how tap-water glue clay into concrete. That's why I bought 3 rain-barrels and hooked them up to 4 garbage cans.

The holes with rain water (pH 5.6), soil is fluffy, thus roots can get oxygen, leaves are dark-green and healthy. Thus the key of fixing clay is to DECREASE the % of fine-particle clay by INCREASING the % of COARSE matter, be it coarse sand, or coarse pine chunks, or coarse organic matter like alfalfa hay or leaves.

The use of gypsum for alkaline soil is to cause clay particles to clump together in smaller chunks, allowing air to reach roots. There's a document that recommend the same, using lime for acidic clay, to break up clay into smaller chunks. I always use gypsum together with sand, its 17% sulfur or acidity and 22% calcium carbonate coat the particles, so they don't glue up together.

P.S. I don't make up stuff just to impress, the info. came directly from the Soil booklet I got when I got my soil tested. Plus I double-check everything I read with Prefern, Ph.D. in Physical chemistry in my Chicagoland. I am an experimenter, and don't waste time in debating. I simply do it, and report the results.