Trying to do research on what kind of soil to build fruit trees but I'm not getting any direct sources. Mulch? Compost? Covercrop? These fruit trees include: Mission Fig, Black Spanish Fig, Sansa Apple, Early Fuju Persimmon, Prolific Paw Paw, Orange Quince, and Lang Jujube.
From my experience, there’s no viable way to build soil to support fruit trees, they’re too large. When planting, I’d ‘amend’ the soil, by adding rotted compost or even richer soil from another area. But after digging some mighty big holes ..and carrying many 5 gal. buckets of ‘soil,’ it ultimately appeared a waste of time as the trees quickly spread their roots far beyond the hole I’d prepared…
Most ‘fruit trees’ seem to prefer a more acid soil, which is what the PNW has, after eons of fir needle droppings I suspect. Top coating applications of ‘acid forming’ fertilizer can help amend the soil some, as recommended for blueberries, but as mentioned, ‘trees’ will go much further than berries or bushes for their nutrients.
I’d once read that ‘the worst thing you can do’ is make a very rich mix of soil for your planting hole, as I’d done; the tree becomes so happy ‘there,’ it makes little effort to reach beyond that enriched soil and becomes nearly ‘pot bound’ as the roots circle within the rich stuff while ignoring the ‘regular soil’ beyond the planting hole. It was also said that water can build in such a planting hole, too, as the soil around it is often clay...
I’ve grown many of what you’ve listed, and they did fine in the native soil of the PNW. The most important aspect of establishing a fruit tree is to eliminate their main competitor for nutrients and water - Grass. Keep the grass back (the further, the better), use a mulch that doesn't create a home (safe place to hide) for voles, deep water (trickling it out to the dripline) and protect them from deer (deer are nearly everywhere).
When the debate becomes chemical vs organic fertilizer/ soil amendments, it's nearly impossible to advise on that, though we’ve likely experts on both around here. Mainly - get those trees in the ground & growing … beyond that, it’s an ongoing experiment for most of us 
You can greatly amend your soil over time. It's very difficult to amend your soil well and quickly. The goal is to have organic matter and microbiology in your soil. What we have done, is what has been most recommended by scientists like Dr. Linda Chalker Scott, who's done a lot of research in this area. Add wood chips. We had terrible compressed clay soil, filled with toxic chemicals. Now we have good organic soil. Wood chips will greatly improve your soil over time. You can probably get them for free from craig's list or an arborist. Mulch is good too. You can usually get leaves for free in the fall. I agree with Viron-get the grass out. ALso, don't amend the hole, like he said. Leave the chips on the surface all over the garden/orchard and let the worms take them down when they are ready. In the long run, if you have a biologically diverse orchard, the leaves will fall and you will get organic material naturally falling into the soil. That's the real way to do it.
John S
PDX OR
Viron and John are smarter than I am about this, so I would go with what they say. What I have to add is, get a soil test.
I thought some of my trees were pale due to iron deficiency. When I got the soil test, it showed an iron level many times over the upper limit. Many fertilizers contain phosphates and potassium. My soil tested as very high in both. What I was mostly low in was Calcium, and a little low in Magnesium. My pH was low, 5.3 so adding lime serves to help with calcium and pH. My soil salts were low, so no problem adding minerals.
I used this place. They make recommendations based on what you tell them, such as 'Starting an Orchard". I don't know if Oregon State has testing, I could not find any state-based lab for washington where I live so used the commercial lab simplysoiltesting.com
One negative, they don't test nitrogen. They state it is too transient.
One positive, if you want, they test for toxic minerals, such as arsenic. That is added cost and I did not do it.
Great tip, Daniel. You certainly knew about that shop and I didn't. I agree that when you get serious about orcharding, a soil test can really help out. If you live near Portland, it is predictable that you will be low in calcium, due to heavy rainfall. I was also quite low in manganese, zinc and boron. Ag Lime is super cheap to put it back in. A great book about this topic is Steve Solomon's "The Intelligent Gardener".
John S
PDX OR
I've been reluctant to do soil testing, in part, because the methodology seems flawed for use in my home orchard. It seems more geared to planting row crops on acreage, where amendments are widely broadcast and everything gets similar treatment.
Its obvious to me that different parts of my yard have different conditions. Sometimes just by going a few feet. Some areas have no topsoil. Some areas drain much faster than other and the soil is a different texture.
If I mix the stuff together, that doesn't help me decide what to do for a given area. And with the expense and time involved, I'm certainly not going to take a soil sample for each potential planting site.
To know what the soil conditions are like in general, I can look up the geological soil type mapping.
What am I missing?
According to GIS I have HcB and HcD soil types, from the Hesson series. The description of which fits my property very well:
https://www.google.com/url?sa=.....8TpBWPfgqA
Hesson Series The Hesson series consists of deep, well-drained soils that are mostly level to gently rolling. Some areas are hilly and very steep. These are moderately fine textured soils that have a fine textured subsoil. The parent material is deeply weathered, mixed old alluvium that contains varying amounts of gravel. The original vegetation is a heavy growth of Douglas-fir and a scattering of western redcedar and grand fir. The understory consists principally of vine maple, salal, Oregongrape, ferns, and red huckleberry. All the acreage has been logged. Areas not in cultivation are in second-growth timber. The understory is similar in composition to that of the native stands. Red alder is dominant in some areas. The annual precipitation ranges from 50 inches to more than 60 inches.
Large acreages of these soils are in cultivation. The principal crops are hay, pasture, and small grain. Some oats and corn for silage are grown in rotation with grasses and legumes. Strawberries and other truck crops are grown to some extent.
Hesson clay loam, 0 to 8 percent slopes (HcB).-This is the dominant soil of the high terraces along the mountain foot slopes in the county. In most places the slope is 2 to 5 percent. The relief is undulating. Slopes are generally short to moderate in length.
In a typical profile the surface layer is dark reddish brown clay loam about 8 inches thick. The subsurface layer is dark reddish-brown clay loam about 4 inches thick. Below this layer is friable, dark reddish-brown clay loam about 10 inches thick. The next layer, to a depth of about 91 inches, is reddish-brown clay. In sequence from the top, the uppermost 18 inches is friable, the next 39 inches is firm, and the lower 12 inches is very firm.
Included in mapping were some areas that are nearly level or are slightly depressional and have a slightly mottled layer at a depth of 30 to 40 inches. This indicates reduced permeability and a temporary perched water table during rainy periods.
This soil is well drained and has moderately slow permeability. The available water capacity is high, and fertility is moderate. Problems arise in the proper scouring of tillage equipment when the soil is worked at about field capacity. Tillage is difficult when the surface layer is nearly dry. Surface runoff is slow, and the erosion hazard is slight.
Most of the acreage is cultivated. Hay and pasture are the chief crops, although other crops are grown, including strawberries, tree fruit, cane fruit, corn, and small grain. Red clover, white clover, subterranean clover, and birdsfoot trefoil are the common legumes. Tall fescue, ryegrass, and orchardgrass are the common grasses. Alfalfa is not well suited, because of the strong acidity and the low content of available calcium and phosphorus. (Capability unit IIe-4 ; woodland suitability group 3dH3 ; wildlife site 7)
Hesson clay loam, 8 to 20 percent slopes (HcD).-This soil is similar to Hesson clay loam, 0 to 8 percent slopes, except that the surface layer generally is 1 to 2 inches thinner. In places where erosion has been active, the surface layer is 2 to 4 inches thinner. The slopes are generally single and are moderate in length. Most areas of this soil are cleared and in cultivation, but use is less intensive than on Hesson clay loam, 0 to 8 percent slopes. Runoff is medium, and the erosion hazard is moderate where the surface is left bare in winter. Most of the acreage is in hay and pasture because the slope limits use for other crops. (Capability unit IIIe-1; woodland suitability group 3dH3; wildlife site 7
Jafar, your point is well taken. Steve Solomon also tells people not to test, and basically just add a mixture of lime and dolomite lime for calcium, pH, and magnesium. His reason is the opposite of yours, which is he states that almost all Pacific NW soils are about the same, so no reason to test. Certainly, different parts of a property can have different characteristics.
I'm still glad that I tested. True, I did not test every corner. For example, behind my house is an area that appears to have had fireplace ashes dumped, plus had a big dirt pile - from what? Because of ashes, I imagine the pH there to be higher, salts higher, and potassium higher, so I didn't add anything there. Weeds grow well there, and I planted green manures - borage (for bees and crowding out weeds) and buckwheat, last year, and those locations have uyoung fig trees, blackberries, and bee forage now.
But I found the testing empowering for most of my yard. It was more comprehensive about what minerals to think about, including trace minerals. To be honest, the things that Solomon stated were correct. My pH was 5.3, calcium was low, magnesium depended on how you think about it, either normal or borderline low. Potassium was high, and iron was very high. I feel that I understand my soil better now, and I certainly won't add any iron, which I had thought about doing before getting it tested.
I did garden for many years without testing the soil. I did fine, but I like that I had it checked. Plus, my property has gone through a number of owners, and I don't know what they added to, or dumped on, the soil.
John, you make an excellent point about lime. I added some last year mostly to vegetable beds. I save eggshells, crush them, and add to raised beds, but I think it really isn't enough. I also scattered lime around the fruit trees last fall, and need to remember to do that this year, too.
question about wood chips - I get them from tree services. Mostly I use them on paths, but would like to add around fruit trees. My friend brought up a concern about possible pesticides used on the trees that were chipped (too late to ask the tree service, the chips are already here). My question is - should we avoid putting these chips around "food" plants? thanks!
Another way to think of it is, what kinds of trees do arbor companies chip? Mostly very tall, like 60 feet tall. You don't spray trees that tall. If a tree is small enough to spray-like 7-10 feet, you usually don't call a tree company. Most people have a brother/uncle/friend who will do it for pie.
So I think that most chips are organic by default.
John S
PDXOR
Idyllwild
simplepress
jafar
Marsha H
Viron
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