I forgot to add this sentence to the first paragraph: but I'm not aware of the advice "never digging into clay", which in your case would only be about 0-2" inches to plant a typical #5 container tree with a 10" high rootball -- no "mounding of dirt" needed. Depending on type of clay and how well it drains, this all may be perfectly acceptable.

Do the drain test: dig a hole, fill with water and let it drain out. Then fill again and time how long it takes to drain out.

Oh yeah, don't plant it 18" deep. Just plant it to the depth it was before, which should already be more than 2" from the graft.

Damn I wish GW had EDIT. It's getting late here, I better hit the sack before I have to edit this edit.

david-
Please save yourself some heartache and just plant them. Don't waste money on bringing in topsoil and do not amend your soil. I am in the exact same situation here as you described. I have the hard yellowish-pale orange clay about 10" deep. Apple tree roots don't go that deep. I was told that apples grafted onto bud-9 stock will only go 6 - 8" deep. Dig your hole 2 feet deep and 2' wide and plant the trees with the bud union 2 or 3" above soil. Don't mound the dirt. If anything, create a small crater so if and when you have to water them, there will be a little pocket so water doesn't run away from the tree when it's dry. See the pics on my page. That's exactly what I did and my trees are flourishing.

I have a similar soil to what you are describing, excepts mines is pretty wet in the spring. Over the past 2 springs I have planted around 70 trees, some using the way you described some just as thomis describes. After the first growing season the ones with mounds out performed the others. This spring the 25 trees I planted just as you described, I dug down to the clay, broke it up a little the placed the bottom of the roots at clay level and mounded up, if needed, to just below the union. Make sure you dont just mound it up, tapper it in to the normal soil level, takes a lot of dirt. I am not saying its the right way to do it but the initial results are good.

8-10" of loamy soil over clay is about 6" too shallow topsoil for fruit trees. Mounds about 6' round, 6" high in the middle would work, or berms down the row.

I'd say your main risk in shallow soil is poor anchorage (trees can fall over).

Dig a hole down into the clay, fill it with water, and see how it drains. If it drains in a reasonable amount of time, then there's your answer. This would best be done as an all winter test.

Yep, I'll stand by what I suggested. If the clay drains well using that drain-hole test method, you have no issue whatsoever, Just plant it -- the clay is not your enemy in this situation. If it has only some trouble draining -- "easiest" thing to me is bring in soil to bring it up another few inches -- mounds/berms will use less soil or go wild and do 6-8" over a larger area. If it drains horribly and if you have shallow hardpan, you got more work to do....

But 15 trees is a lot of investment -- I'd have done a soil test and dug deep in a few areas to know what I was dealing with before I'd plant, IMHO.

Personally, and if the trees are bareroot, I'd dig out the loam from each hole and put it in one pile, and dig out the clay and put it in another. Then I'd plant the trees returning the clay first then the loam, rebuilding the soil stratigraphy. The new roots will go where they want. This incidentally is dead opposite of what tree-planting information was decades ago. They would reverse the stratigraphy.

David You need to do a drainage test of your soil before you do any thing else.

HereÂs how you do it.

Dig a hole 6-12" wide and 18" deep. Fill it with water and let it drain over night. The next day fill it again, If it drains out in less than 4hrs you are all good to plant your trees.

If the water does not drain then we need to discuss mounding our raised beds but lets not get ahead of ourselves.

When you are ready to plant the trees. Plant them the same depth as they were planted by the nursery you received them from. This goes against what some have posted above. However planting to deep can cause you all kinds of problems later at the graft union.

More after you do your drainage test.

Bananas is right about keeping the soil strata as it is. If you don't have a terrible drainage problem your trees will be fine.

I've seen commercial apple orchards in clay soil where in early spring the water just sits on the surface, but by the time trees begin leafing out they find enough oxygen for very vigorous growth. I used such an orchard as a nursery site to grow bearing age trees after making a deal with the grower. The trees grew great.

If other species of trees (not willows!) are growing well in this soil, I'm sure you're fine, if not, run with berns made from existing soil. Testing the drainage as mentioned is also a great guide line, but I wonder how the soil in the orchard-nursery I mentioned would have tested out.

Harvestman wouldn't the variety and rootstock come into play for *some* of the trees? He didn't state what type of fruit trees. What if most of the trees are cherry on Mahaleb or Gisela? Or even if apple, on M27? Just curious how much you would take this into consideration for non-apples.

Sebury, at the site I mentioned the peaches did well also and there was no 10" top of black loam. The soil we're discussing here sounds reltively good to me but I'd actually have to see it to really know what I'm talking about.

Still, your point is quite valid and root stock and species sure play into adaptability to a poor drainage situation.

Sounds like newer construction (70Âs or newer). The trend was, and is, to strip away the topsoil use clay to back fill, then top with a thin layer of topsoil. You may find sand or another type of soil another foot down.

If you are going to plant pear, apple or European plum you should just plant "as is". These trees do not seem to have a problem with clay, they bite right in and do fine. Peach or cherry will have problems unless you dig a pit or build a raised bed. Some newer cherry rootstocks will tolerate some clay.....so I would say it depends more on, which 15 trees, you are going to plant.

I doubt they would have brought back a 10" layer of topsoil. Sites like this I see only bring back enough soil to grow grass- 3-4 inches.

When the soil fails the percolation test suggested by thisisme, I plant the new tree right on top of the soil, dragging the soil from around it to cover the roots. Lightly tamp it down adding enough depth to equal the previous depth. Mulch well, watch the first year to keep moist. If tree was planted with any foliage remaining(mine never are)you will probably need to stake for the first year. Al