When it comes to root health, pots with gas permeable walls carry the day. Terra cotta clay pots are better than plastic or vitrified clay pots and fabric pots are better than terra cotta clay. The reason is greater gas exchange through container walls and the fact that an increase in gas exchange comes with an increase in evaporative water loss, which can be a lifesaver when using water retentive media. There will still be a PWT in these pots, and for any given medium it will the same ht in a pot with rigid sides as in the fabric or air pots at container capacity. Container capacity is a measure of how much water the grow medium in a pot or container holds at the moment it has stopped draining after having been watered to the point of complete saturation. The ht of the PWT and how long it affects root function is usually key/critical in determining what opportunity a plant will have to realize as much of its genetic potential as possible (within the limiting effects of other cultural influences). The factor that most affects the ht of a PWT is the size of the particles from which the medium is made. So, reducing the duration of PWTs limitations increases the opportunity for plants to realize a greater measure of their genetic potential. But wait! There's a more important consideration. If you place your fabric containers directly on the ground/soil, from the perspective of hydrology it changes the fabric container to a raised bed; this, because water is free to move through the fabric between the grow medium and the earth, with the earth acting as a giant wick. This means, because of the increase in the force of adhesion in the mineral soil beneath the pot (due to a mineral soils much larger o/a surface area on a per volume basis), water in the soil will be pulled downward with enough source to overcome the capillarity holding it perched in the container. As long as you don't place the fabric container on coarse sand, peastone, or other large particles, the earth will likely pull all perched water from most media one is likely to use in a container. I've mentioned this and the fact that healing in your pots situating them directly on top of soil turns them into raised beds. the only caveat being it's essential that there is a 'soil bridge' so there is continuity of the soil column between the soil (earth) and the grow medium in the container, through the drain hole(s), so water doesn't have to jump an air gap to exit the container. This applies more to pots with rigid walls and is not a factor when discussing fabric containers. Al

You're welcome. Thanks again, for being so kind. Some thoughts I offered in another, older threads on this forum. They should pretty much answer your question, and may even be quoted in the text somewhere up this thread (if so, I apologize for the redundancy): In my estimation, the only case to be made for reusing container soils is one of economics, and you'll never find me argue against making that decision. If you can't afford, you can't afford it. That said and setting economics aside, you might decide to reuse soil for reasons other than economical. Perhaps the effort involved with acquiring (or making your own) soil is something you might not wish to go through or be bothered with. In any case, it would be difficult to show that soils in a more advanced state of structural collapse can somehow be preferred to a soil that can be counted on to maintain its structure for the entire growth cycle. So, if the economic aspect is set aside, at some point you must decide that "my used soil is good enough" and that you're willing to accept whatever the results of that decision are. All soils are not created equal. The soils I grow in are usually pine bark based & collapse structurally at a much slower rate that peat based soils, yet I usually choose to turn them into the garden or give them over to a compost pile where they serve a better purpose than as a container soil after a year of service. Some plantings (like woody materials and some perennials) do pretty well the second year in the same bark-based soil, and with careful watering, I'm usually able to get them through a third year w/o root issues. Watering habits are an extremely important part of container gardening. Well structured soils that drain well are much more forgiving and certainly favor success on the part of the more inexperienced gardeners. As soils age, water retention increases and growing becomes increasingly difficult. If your (anyone's) excellence in watering skills allows you to grow in an aging medium, or if your decision that "good enough" is good enough for you, then it's (your decision) is good enough for me, too. The phrases "it works for me" or "I've done it this way for years w/o problems" is often offered up as good reason to continue the status quo, but there's not much substance there. I'm being called away now, but I'll leave with something I offered in reply on a recent thread: "... First, plants really aren't particular about what soil is made of. As long as you're willing to stand over your plant & water every 10 minutes, you can grow most plants perfectly well in a bucket of marbles. Mix a little of the proper fertilizers in the water & you're good to go. The plant has all it needs - water, nutrients, air in the root zone, and something to hold it in place. So, if we can grow in marbles, how can a soil fail? Our growing skills fail us more often than our soils fail. We often lack the experience or knowledge to recognize the shortcomings of our soils and to adjust for them. The lower our experience/knowledge levels are, the more nearly perfect should be the soils we grow in, but this is a catch 22 situation because hidden in the inexperience is the inability to even recognize differences between good and bad soil(s). Container soils fail when their structure fails. When we select soils with components that break down quickly or that are so small they find their way into and clog macro-pores, we begin our growing attempts under a handicap. I see anecdotes about reusing soils, even recommendations to do it all over these forums. I don't argue with the practice, but I (very) rarely do it, even when growing flowery annuals, meant only for a single season. Soils don't break down at an even rate. If you assign a soil a life of two years and imagine that the soil goes from perfect to unusable in that time, it's likely it would be fine for the first year, lose about 25% of its suitability in the first half of the second year, and lose the other 75% in the last half of the second year. This is an approximation & is only meant to illustrate the exponential rate at which soils collapse. Soils that are suitable for only a growing season show a similar rate of decline, but at an accelerated rate. When a used soil is mixed with fresh soil after a growing season, the old soil particles are in or about to begin a period of accelerated decay. I choose to turn them into the garden or they find their way to a compost pile. Unless the reasons are economical, I find it difficult to imagine why anyone would add garden soils to container soils. It destroys aeration and usually causes soils to retain too much water for too long. Sand (unless approaching the size of BB's), has the same effect. I don't use compost in soils because of the negative effect on aeration/drainage. The small amount of micro-nutrients provided by compost can be more efficiently added, organically or inorganically, via other vehicles. To boil this all down, a container soil fails when the inverse relationship between aeration/drainage goes awry. When aeration is reduced, soggy soil is the result, and trouble is in the making. I've mentioned before that I don't post here to get people to convert to a particular mix or blend of soil. I post what I know will work very well for anyone who can get appropriate ingredients & modify the mix to suit their climate & other cultural conditions. If you use a mix that guarantees good aeration for the expected life of the planting - you're in good shape. Most peat based mixes will not work well in extended life plantings. Conifer bark based mixes, on the other hand, retain structure for much longer periods. If you still have questions, please don't hesitate .... Al

Al and Nathan, I hope that you don't mind my sharing a humorous story about Turface, that really highlights your points and underscores how respected a product Turface is in the industry. My son is a Turf Grass Agronomy major at a large Southern university, and did an internship last spring/summer at one of the major league baseball spring training facilities in Florida. Turface is used for excess water on the fields that occurs during rainstorms, especially those "popcorn" showers (downpours) that occur frequently in Florida. It has helped prevent many a game "rainout" due to its effectiveness. It takes many bags of Turface to do this (for one game), which can become a bit pricey---so it's a protected commodity in the baseball industry. During one sudden torrential downpour, the Grounds Crew quickly pulled the tarp over the infield, and then took cover in the visiting team's dugout to wait out the storm. The Turface bags were kept to the side in the visiting dugout, near where the Grounds workers were standing. The visiting team's pitcher had a bad inning just prior to the rainstorm, and came into the dugout kicking and throwing things, as they sometimes do. As he looked for things to use to vent his frustration, he eyed the bags of Turface to the side, and the Grounds workers caught his glance, and could tell that he was tempted to kick them, also. They immediately, in *unison*, said "don't even think about it!". Throw your glove, knock over some bats, kick the bubblegum containers over, but don't mess with the Turface...unless you want to take on the Grounds Crew... :)

Philoz, I used Air-Pots last year. I used them only for rooting (which will change this year) but they come in sizes to 120 gallons. One of the nice things about them is they are shipped flat. Therefore, the assembly involves one to wrap the flat sheet and secure it with a "fixing" (in my case its something very similar to what holds the upholstery into your automobile sheet metal.) When it is time to repot/root-prune, you can remove the fixing, and unwrap the container from around your tree in place. This is necessary because of the design of the container, but it comes in handy for other reasons as well. The overall design of the container is suppose to prevent (or at least minimize) many root problems associated with container growth. I found it to be moderately successful. I posted on the use of the pots in this forum. I think I just titled it "Air-Pots". I seem to remember a distributor in Australia. good luck, ~james