You shouldn't have to depend on soil fauna for aeration, it should be built into the soil and you should be sure that the soil is able to remain structurally sound enough to ensure that it will retain adequate aeration for the intended life of your planting. If it will not, you invite those several issues associated with a collapsed soil and you should be thinking seriously about replacing it and turning the old into garden/bed/compost pile. Also, it's best if you resign yourself to the idea that you, not the medium, is ultimately responsible for the plants' nutritional needs. There is nothing the earthworm can offer in containers that you cannot find in other organic or chemical products. In short, their contribution to a more rapid deterioration of a soil that is already well advanced in it's structural collapse is not something I would welcome. Cut/pasted from another of my posts: 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. Al

I just want to mention that I did indeed Google and want to share what I found. I found that there are many native North American earthworm species that existed on the continent before the arrival of the Europeans. However, they did not live in all regions. In particular, regions that were covered by thick ice sheets (e.g. Great Lakes region and Canada) did not have any native earthworms prior to European colonization. That's what Jeri is referring to. In much of the rest of the country native species did and do exist. California, for instance, has its own native species of earthworm that exist nowhere else in the world. We are not likely to see them in our yards, though, because they are greatly disturbed by tilling and have mostly been displaced by non-native species. However, in the wilderness areas they still exist. They are adapted to our dry climate with a winter rainy season and exotic worms don't much care for that. The Pacific Northwest has many species of native earthworms, including the Oregon giant and Palouse giant, both of which are rarely seen and may be headed for extinction. The East has its own native species of earthworms, too. A search on this web page shows at least 108 native species: http://www.discoverlife.org/mp/20o?guide=Earthworms

I garden with mostly organic methods, but do use some fertilizers that would be labeled non-organic. I also find that the worms are not adversely impacted by my fertilizer applications. In fact, since my large worm bin has a very large amount of browns, I periodically add some urea pellets (46-0-0) to the bin. The urea addition is a trick I learned from commercial worm producers who use it to increase worm sizes and population densities. The worms thrive with this kind of treatment, and it really helps to decompose the piles of browns. In my opinion, gardening with organic materials incorporated into the soil does not have to be separated from the use of some other fertilizers. In my case, for the various crops I produce, I feel that I would not get the excellent crops I do without the extra fertilizer additions, or without a lot of extra work or cost to add all the materials in a pure organic fashion. I believe that if I put to much fertilizer in for the worms, it will also be too much for the plants, and they will show the adverse results. I call my produce naturally produced, since it is based on organic methods, but not to the letter what organic means now legally. People like the taste, and quality. Renais

A blanket statement that worms do not belong in North America is simply wrong. But that's not what the writer of the Boston Globe article, nor the researchers interviewed have stated. What they have stated is that the forests in what had been glaciated areas (ie., the forests northeast of New Jersey) evolved earthwormless, and developed into ecosystems where a thick duff layer always existed, and so had a variety of organisms that depended (& still depend) upon that duff layer for existence. The earthworms destroy that duff layer, radically altering the forest by diminishing its habitat quality.