Concrete is made by mixing sand, water, gravel/rocks, and CEMENT. Without the cement you cannot make concrete. Clay particles in soil are already seated closely with themselves. As was mentioned, adding sand is not always a cure, but it's not necessarily bad. Adobe bricks are made by mixing low sand content soil with grassy stuff (like straw), plenty of water, mixing it vigorously to drive the air out of the mix, and letting it dry into brick forms. Driving out the air is important to the adobe process. Good soil is often a mix of clay, sand, and loam. But as for the clay, chances are very good the original poster did not have clay at all. We've learned a lot on the various lawn forums in the 9 years since this post was started. It is much more likely the OP had an imbalance of salts creating clay-like conditions. Adding silica sand does not change the salt balance. Adding limestone sand can make it worse or better depending on the chemistry of the original soil. Today we would have suggested the OP get a soil test from Logan Labs and post it here before adding sand or anything else.

The ('dug out') in-ground 'raised' beds are what I use. I too have clay (although I don't have the pH issues you have,) but I've been planning my beds for a long time. I've been throwing small amounts of my grass clippings into the space I turned into this year's garden for about 3-4 years. Clay, aside from its horrible tilth issues, is usually very nutritious. Therefore, why not take advantage of the free resources. Basically, I just tilled the soil, mulched heavily, then planted. In the fall the mulch will get tilled in, and I'm already preparing the organic matter to add for next year. The more compost and organics you add, the more 'raised' they will become. If you have fairly good drainage, and this is just my opinion - everyone will have their own reasons for their decisions - the only reasons to box in and 'lift' your beds are for organization, esthetics. and for those who have difficulty bending down low. Here's what my beds look like... When I was younger, I used to work all my beds (a lot of them!) by hand. Breaking new ground with a pick ax and a digging fork. Turning-in organics with the fork. Now, lol... not so much. I borrowed a relative's tiller and after the ground was broken well, I worked the soil by handling the tiller from the side. That way, in the final passes, there was no walking on the freshly tilled ground. Now that the hard work for these beds are done, I'll add a couple new ones each year as my sunlight allows (I need to top a few trees on the south.) Anyway, sounds like you have the beginnings of a plan. There's a lot of good advice on this site, take a little of this, and little of that, and find what works for your situation. There are people who have a lot more knowledge than I. When something comes along that is better - whether it be knowledge or tools... upgrade!

Someone here is having good results with amending clay with 50 percent sand and then topping the area with sandy loam. The nurseryman who runs Laguna Hills Nsy and gave the soils class takes the stock he buys and removes most of the mix around the roots. Then he replaces it in peat moss, perlite, pumice,sand and some charcoal. He would add more sand in the mix he sells bagged but the bags would rip or be too expensive to ship. The charcoal is there because the world's best soils have some charcoal content. A building supply in Costa Mesa sells something called Rick's mix that is sandy loam and decomposed granite for improving clay. I have used the best potting mixes I could buy and watch the plants die off in a year. With the mix from Laguna Hills, it doesn't happen. Now I use a mix of my own soil, sand and the Laguna Hills formula. I have been making charcoal all winter and sifting it to throw out the ash which is alkaline. In the old days the nurseries planted in Sandy loam and sold bareroot. No one amended the holes or they planted high in large mounds or raised beds if drainage was poor. Now the wholesalers who planted in real soil are being edged out by those who plant in composted wood. The plants grow fast and are lighter to ship but eventually the breakdown of the planting material kills the plant. You can slow the process by letting the mix dry out almost completely before watering again, but it stresses the plants, especially in our warm climate. In the old days, a nursery could water every day with no root problems at all. A nursery could keep their stock for years and water every day and feed once a month until it sold. Now it's a race to sell the plant before the mix degrades and the roots die. The nurseries have to move their stock quick before then. Even if you plant it in good soil, the plant might not make it to five years because the mix around the trunk has become poisonous to the plant. Some plants grow fast enough to get roots out beyond into good soil. Arborists use augers to drill out holes around the trunk and backfill with sand to get the oxygen into the toxic area. You can also dig into one side and replace with 100 percent soil and six months later do the other side. The formula is stay away from three times the diameter of the trunk when removing roots. That was the formula for moving plants sold in soil wrapped with burlap. Any plant you fix needs to be shaded for two weeks. You can also help them by spraying the leaves with 1 gallon water 1 oz Karo syrup 1 oz seaweed 1 oz fish fertilizer a little wetting agent I hope this helps anyone trying to save a plant. I think it's rotten that plants are being sold that they know will have problems later on. People think it's their fault. The landscape reflects the trend towards only plants that can overcome the crappy potting mix and we all get taught wrongly to add this stuff to the soil at planting time.

I guess if you purport to speak with more authority on the subject than those who spend all their time researching and studying these issues, Embothrium, then feel free to call that false. OTOH, I tend to give more weight to opinions of actual horticultural scientists : "Let's say you have incorporated the recommended 25-50% organic matter to your backfill. (Remember that an ideal soil contains 5% organic matter by volume.) The initial results are positive; roots grow vigorously in this ideal environment as long as irrigation is provided. But what happens when these roots encounter the interface between the planting hole and the native soil? Native soil contains fewer available nutrients, is more finely textured and is less aerated. Roots react much in the same way as they do in containers: they circle the edge of the interface and grow back into that more hospitable environment of the planting hole. The roots do not establish in the native soil, eventually resulting in reduced growth rates and hazard status as crown growth exceeds root ball diameter" The Myth of Soil Amendments, Linda Chalker-Scott, PhD