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

I have my bog bean planted in soil in pots as it sends out long runners so may be seeking other places to pot itself. It's one of the earliest plants in my pond to green up. The ice left this weekend and the plant is already greening. Some plants don't like fast moving water. I've heard watercress likes it and I got some last year but it didn't like my pond or something as failed to thrive. I've found that when I plant parrot feather in dirt it gets bushier and grows faster than if just stuck amongst the rocks along the edge. My iris that were planted in gravel havn't done as well as the ones planted in dirt in pots although on another pond site on vege filters the guy swore by Iris bare rooted in gravel as long as the water was moving through the roots was better for filtration than any other plants he had tried. So I guess bottom line is try both.

You don't ever want to dig the planting hole any deeper than the nursery container or rootball is anyway and it is a pretty darn big plant that totes around a rootball deeper than 12 inches!! So you should be good to go. FWIW, the vast majority of plants - even large trees - have the bulk of their root mass within the top 12-16" of soil. And for the most part, roots grow laterally, not vertically so out, not down :-) 12-18 inches of workable soil is a very reasonable amount.......a lot of new construction efforts will grudgingly lay a couple inches! Gravel is a common backfill for any type of retaining wall. And yes, it is there for drainage purposes. However I doubt that gravel is uniform throughout that upper tiered portion - usually it is concentrated immediately behind the wall.....right where you are digging :-)

Thanks gardengal48! I planted twelve 3ft brandon cedars about 4 weeks ago. The first week I was hand watering the base of the tree with the hose everyday for about 10 second a tree. I couldnt see any water pool up the soil was taking itas fast as I could give it. The very tips of the tree started to turn really light green. I called the place I purchased them from and he said they are probably getting too much water and to dial the watering back to once a week and really really soak them. I've been doing this and now I can see that down low on the tree it's starting to go a dark slight gray color and there are sprouts that are dry and not continuing to grow near the bas as well. The very tops of the trees look good and healthy. Am I being too paranoid? I have excellent soil where I live. It's deep black fluffy soil half inch down to about 18" then it's sand. I've never seen my soil dry more then 3/4" down before