Wow - you guys have been busy while I put in a long day. Dan A fine-textured horizon underlying a coarse-textured horizon retards saturated flow (my emphasis) because the small pores do not transmit water as quickly as do large pores. I mention this because it's an important point. From the practical perspective, for both containers and raised beds, we're not really interested in how fast the perched water percolates through this layer (as long as it's not hours and hours or days, and this is a horticultural issue, not a scientific one), only that it does. We have now established that a soil strata that will support a PWT under some conditions (as when it's in a container) and that is resting atop a layer of finer soil will drain into the lower, finer strata, which is a 180* reversal from your original premise. We can probably also agree that the same strata of soil that will support a PWT will not drain when it rests atop a very coarse layer. We know the point at which the capillary pull of the lower strata + the gravity flow potential equals the capillary holding power of the top strata is the point at which the top strata will drain. Let's argue the science through practical examples & see where that leads us: Let's assume we have a container soil that will support a 4" PWT in a container (call it CS4) and we have a 12" deep container. We'll also assume that we can do magical things like setting a soil mass complete with a PWT atop another material. 1) The most important part of the discussion to container gardeners will pertain to what happens when there is a very coarse layer of material under the CS4 soil. Nothing. The CS4 soil will retain 4" of perched water @ container capacity regardless of how much water is added to the soil after container capacity, and regardless of the soil column depth (as long as it is deeper than 4". If it is less than 4" deep, the entire soil column will simply remain saturated.) 2) A homogeneous CS4 from the top of container to bottom will also retain 4" of perched water @ the bottom of the container @ container capacity regardless of how much water is added to the soil after container capacity, and regardless of the soil column depth. My contention is also that if the CS4 was layered atop another strata comprised of particles up to 2.2X the particulate size of the CS4, there would be no impediment to drainage, but this is a minor point & not important to the discussion. 3) If 4" of CS4 is layered above 2" of dry sand (lets imagine that the sand will support a 5" PWT in a container), perched water will move out of the CS4 into the sand until it is saturated. At that point, some or all of the water will perch in the CS4, depending on whether or not the water column has enough gravitational flow potential to overcome the capillarity of the sand. 4) If 4" of CS4 is layered atop 6" of dry sand, all the perched water will move into the sand, as long as the total air porosity of the 6" of sand is greater than the volume of perched water in the CS4. The soil column section would 5 reveal 5" of sand with perched water - 1" of sand with no perched water, and no perched water in the CS4, regardless of height. 5) Now lets use a practical example for raised beds. You have already reversed your position and allowed that perched water will move from a strata of coarser particles into one of finer particles. Since the soil being discussed on the SF forum is a sandy loam, we know that the raised bed soil is very similar in structure to container soils. If it is fine enough to want to retain ANY perched water, we have already seen that the water would readily move downward into the sand unless the sand is saturated. To illustrate this, hold a saturated sponge with the large surfaces horizontal until it stops draining. Set the sponge on several layers of paper towels and note how much water moves into the paper towels. Back to the raised bed ... Since we know the organic mix will freely drain into the sand, sandy loam, even clay loam it makes incorporating any organic material into the native soil a superfluous exercise. Now, in the case where the soil might actually BE saturated, we are warned that incorporating organic material into those soils prone to saturation very often creates the bathtub effect, it should be avoided. You cannot use the argument impermeable in either raised beds or containers because the water is free to move laterally into either thin air or through/under RB walls. If not, it is certainly free to move laterally as the surface of surrounding soil dries. I'll say this gently, but you accused me of working from faulty premises and logic, and of course I disagree. You also accused me of obfuscation, and introducing irrelevant examples several times, yet a couple of paragraphs later you introduce "exfiltration (and evapotranspiration)". Your "Why wouldn't one incorporate nutrients as deeply into the soil as possible?" seems to be irrelevant because your initial justification was that it would eliminate a perched water table. You may note that I've not had to do any back-pedaling on any of my statements, and I haven't had to add qualifications like "generally the rule of thumb", "for most purposes", "this modifies my assertion". You also keep making the point No Gravel, but no one ever argued opposite that point. "I'll try to be a gentleman if you'll be fair. If you read my posts again, you'll see there are few on these forums that remain as focused on the core argument as I. I'm not in thge habit of introducing extraneous points to avoid the issue. I also disagree with Generally, the rule of thumb for larger particle size below is the entire column for most purposes must be saturated to drain. Not always, but if you are advising someone and state this you are correct 85% of the time. As I illustrated above, a soil that supports 4" of perched water in a container will ONLY support 4" max. It's 11 here now. I've been up since 5 and had almost 10 hrs on the road, so I'm weary. I hope what I said is easy enough to string together and understand. ;o) Take care. Al

Hmm, my lawn seemed to have progressed quite rapidly past 2 days. The only reason I'm asking about core aerating is because I noticed one spot where I used to have a small tree before moving it to a different spot last year and it's the greenest spot. My guess too much grass or runners overlapping each other contributed to significant winter kill. Considering that Floratam and Sapphire are very aggressive grower, I'll have to cut back on fertilizing not to produce excessive growth. The area that are most trampled on are greening up the fastest as well. It was completely brown, you'd think I had total winter kill. I may end up going with Biozome instead of core aerating. How will I get to home from rental place (no truck)? It's heavy as heck . It doesn't seem to work too good if the ground is too dry. Must be right amount of moisture to maximize coring depth. It hasn't rained much in a while and the ground is starting to get dry. Last thing I want to do is water during the spring when it's supposed to be wettest period of the year.

Olpea, if you don't like the invigorating affect of woodchips (and, as you know, it is an issue that also concerns me with mature fruit trees) you may hate the invigoration caused by hay mulch with its higher N content. Straw might be an exception to this problem. Voles love both. Hay really pushes growth in my nursery when I use it, seemingly more than chips. I doubt this excessive invigoration is an issue where there isn't much rain during the last couple months of the ripening process if you keep the trees a bit thirsty. I'm going to do some experimentation with woven fabric covered by white course gravel (small stones) to see if reflected light is helpful here. I realize that would not be practical for a large number of trees, but it may be a semi-permanent solution and the gravel might create problems for the voles by pouring into their tunnels. Most of all, the reflected light might reduce fungus pressure and push up brix. I have a customer with a courtyard that is maintained with white gravel on the ground and white walls and the apples growing there have exceptionally high flavor. In 25 years of working on estates that often use large quantities of shredded wood chips and also using them in my nursery operation, I have not experienced any disease problems with wood chips either, but that doesn't mean that Drew doesn't have a good reason not to use them where he is. I do believe that woodchips are more likely to help trees through drought than become a problem. I think an awful lot of water is stored in the rotting wood that wicks into the soil by capillary pull as the soil dries. I've never lost a mulched tree to drought even without pulling it away when it becomes dry. Shredded wood is more likely to mat up in a way that repels water than chips out of the chipper. It is also more likely to tie up nitrogen because it breaks down faster. The last sentence may seem to contradict the idea of woodchips invigorating trees, but that affect occurs over time as the chips convert to a rich compost that releases N and also supports life forms that actually pull N from the atmosphere.

There is a good chance that the rocks do cover a drainage pipe; plus they will discourage termites. That isn't a very wide area - I'd widen it just enough to be able to walk on it - you definitely do *not* want plants too close to the house-siding (otherwise you will be battling mildew, moss, mildew, insect access, mildew, etc). However, if you put a variety of medium and tall plants in front, no one will notice the gravel, while the plants will appreciate having good air circulation. I have similar on two sides of my house and the only person who ever noticed the space (and realized it was actually wide enough to walk on), was a professsional landscaper. I have a mix of hedges and bushes in front of the gravelly area, and flower beds in front of the hedges. The bed's front edges are gently curved (for easier mowing, but it does look good). Take time to sketch the mature heights of your preferred greenery, and be sure to have a selection of heights, widths and foliage color. To get feel for it, you can experiment with arranging annuals that are of different heights this year - and you will be surprised at how much better the place looks with greenery and flowers to soften the architecture.