I'm not sure how much container growing you've done, but after a while you develop a sense of what's happening below the soil line. E.g., if I'm watering a plant in a gallon of medium and it's nearly dry, I can usually predict within an ounce or so, how much water it will take to saturate the soil (so water starts to run out of the drain hole). In your case, you should be able to consider how wet or dry the soil is, what the soil volume of the pot is, and about how much water it will take to moisten (as opposed to saturate) the medium. Next time your plant needs water, you might need to fuss a bit by adding the water slowly enough that hydrophobic tendencies don't thwart your effort to moisten the medium, but pay attention to how much water you're applying. I'd guess that in a water-retentive mix, it might take 12 oz of water to rehydrate a gallon of medium so it's moist instead of wet. By simply paying attention to what you're doing, it should take only a couple of waterings to get a feel for the difference between too much and just enough. Honestly, unless you enjoy being passionate about trying to make everything as perfect as possible, you're probably wringing your hands too much. You know I said that in a friendly way because there was nothing critical about it. If you're having fun - that's what matters. If you're creating stress by trying so hard, I'm just trying to let you know it doesn't have to be stressful. Al

Mulch mowing is always recommended. It is especially important to do it with sandy soil. He should not bag his leaves. Instead he should mulch mow them into the soil. Mulch mowing can account for up to 25% of the lawn's nitrogen needs. In theory peat moss can help. Peat moss can (often) get a fungus on it which makes the it water repellent. The solution to that is to spray it with a surfactant like shampoo at a rate of 3 ounces per 1,000 square feet. A faster way to build the organic matter is to fertilize with organic fertilizer like soybean meal, corn meal, alfalfa pellets (rabbit chow), corn gluten meal, or Milorganite. Now is the time to apply. With a partly shady lawn he'll have to water the different parts differently. Here's some general theory on watering. Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall.

Perched Water Table (PWT) is by definition has to do with gravity. Gravity is supposed to pull everything down and yet you find saturated layer of soil in containers and on certain geological formations on earth. That saturated layer of soil that seemingly defies gravity is PWT. There does not need to have a impenetrable layer to have a PWT. Take a very wet sponge and let it drain and then hang it in air. There will still be substantial water in the sponge that you can squeeze out. That water is held in there by capillary forces and gravity cannot overcome it. Same happens when there is a coarse layer of soil below finer layer of soil. The coarse layer has much less capillary force compared to the finer layer and thus the finer layer holds on to the water - just like the sponge in air. Gravity always has an impact. The capillary forces are also powerful. The height of PWT determined by both when they cancel each other out. Finer the soil, smaller is the air space and higher is the capillary force pulling water along the surface of the particle. Capillary force depends on the size of the air space. Size of the particle is incidental here. You can get the same effect using a very fine glass tube. If you dip one end in water the water will rise up through the tube because of capillary action. Finer the tube's inner diameter the larger is the upward force. Your balloon example is also incorrect. Try to wet very fine dry peat moss and you will be frustrated. On the other hand once it gets a little wet it can absorb lot more water. Hydrophobicity occurs with some types of particles such as peat moss because the adhesive force between water and the particle is much weaker than the cohesive force between water molecules. In case of peat moss, the adhesive force is very low when dry but increases tremendously once slightly wet.

Does anyone have a link to a study that shows a water retention curve for Turface? Here is what such a curve looks like for Peat: What is important to measure in such a graph is the percentage of water originally held in the substrate that is available to the plant. For peat, roughly 50% of the moisture is released to the plant before the substrate tightly holds onto the remaining water, right around 5 kPa.