The soil on my property varies considerably. Some spots are 4' deep(at least as far as I have dug) of a very fast draining, sandy loam. Other portions have a more compacted clay type soil and about 12-16 inches deep is usually very hard soil bordering on hardpan.

I add a small amount of compost and other organics when I plant. I feel it helps my maples and conifers withhold at least a little bit of water during our long, warm summer days. There isn't a 'bathtub' effect though as the amended soil is about 10% of the soil used to refill the hole. I'd say it's more akin to fertilizer spread amongst the outer roots.

My own practice has been reinforced by results. Japanese maples planted with no amendments(even with 3" of bark), particularly in my driest/fastest draining spots quickly struggle and/or die. I've had success replanting maples in the same spots with about 20-30% of the hole amended with organic material and composted pine bark.

I'd say while information like this is useful as a general rule, gardening results vary dramatically based on the plant types, sun exposure, climate and availability of water.

I've had a 40-year veteran of Japanese maples(growing them for 40, he's over 60) suggest at least 1/2 amendments in our local climate here.

While amendments may not help many plants(and even harm some plants), there are situations where it is viable/critical.

Not trying to argue Dave, just provide some perspective.

-Will

This is a open discussion and all opinions have value.

As I said... "if it works for you...go for it".

Dave

In other, scientifically organized and conducted trials dating back to the late 1960s treating various combinations of plants with various types and amounts of amendments has consistently not demonstrated a benefit.

Soil amendments arguments have raged on for years here at Garden Web, searching the forums is liable to produce related discussion.

What have I observed in my garden: till in aged pine fines and I can grow dwarf Abies, plant any abies directly into my hard clay and I have a dead plant. Breaking up my soil with the Pine Fines seems to have been beneficial in my situation. My view is go with what works for you in your specific area of the country and with what you are growing.

If you amend a big bed the plant gets the same soil texture throughout - except for what comes with it on the root-ball. A specimen stuck into an unloosened clay soil with an intact potting soil or sandy field soil root-ball is liable to have the same problems as one stuck into a small amended hole. The main cause for difficulty is how water moves into and out of areas of different soil texture. A pocket of one texture surrounding by a larger area of another texture often serves as a collection point for water during wet conditions (when amending of backfill has given the planting hole a coarser texture than the surrounding soil). During dry conditions the reverse may occur, with the finer-textured unmodified soil around the planting hole having a greater attraction for water. I have seen plants with intact potting soil root-balls that were dust dry years after planting. The last one was being dug recently, to rescue it from a garden that was being let go. Well into our rainy winter season the potting soil zone was as dry and intact (not obviously decomposed) as could be.

LOL. I read bed time stories to my plants every night before i tuck them in. Heck, sometimes i even put on Baby Einstein for them.

Well of course one can not control the soil in the pot that you bought your tree in. It won't be the same as your soil. I don't know what can be done to fix that. But, so far I have not had a problem with uneven soil conditions, or at least I have not seen a problem. I had more plant deaths before I started improving the soil. In the case of me forgetting to water, the improved soil holds the moisture longer, but the opposite applies to clay, and I have sand.

This research is over a pretty limited area. I haven't planted a field grown plant in along time. Every thing I plant comes out of a pot. I also never just plant one woody plant but rather I prepare an entire bed with lots of free city compost and a bit of gravel. My garden is a large double city lot and in the last three years I have added 130 yards of compost to my site. You can imagine why I find this research concerning. I always thought that the reason soil wasn't amended when digging a single whole was to avoid creating a bathtub where a plants roots would sit and that plants planted in superior soil would get "lazy" and not spread out. It seamed this author was against using soil amendments for woody plants in general. I hope he is wrong.

beano58, I doubt you have anything to worry about :-) This article, and others similar, are focusing on the widespread practice of restricting the application of amendments to a specific, limited planting area - primarily just the planting hole. If a significantly larger area is amended - like the entire planting bed or even the whole garden - much of the objections become moot. Even the article makes this distinction: "surprisingly, plants in the mechanically terraced areas, which involved excavating and amending a large planting area (not just the planting hole), had better growth and survival rates."

In many cases, working with the indigenous soils will work just fine. But, depending on the plantings involved, amending poor, compacted, compromised drainage or low fertility soils may very well be advised. You are in fact then attempting to establish plants which may or may not be appropriate to unamended local soil conditions. And few of us have home landscapes where the soil has not already been altered to some degree, if just by the construction process.

When amending a large, extensive area is not practical, then I do support the contentions outlined in the article. One either plantes in raised beds or berms of imported soil or utilizes only the native soil with any amendments provided in the form of mulch.

For more on soil amendments etc.

Here is a link that might be useful: Horticultural Myths

I have successfully transplanted hundreds of tree seedlings (mostly bare-root, my preference) in the past 24 years and never amend the soil.