Fixing wrong planting technique

I’m reading Edible Forest Gardens by Toensmeier and just found out I made many mistakes when planting my food forest last winter (August), one of which was the digging of the holes.

Topsoil was at most 30cm deep and very compacted, followed by heavy clay. Naively, I thought the best would be to dig deep and backfill with a mix of topsoil and compost (mushroom compost, the most easily available for me). Also, since there was little topsoil, the mixture was heavier on compost than soil, and since there wasn’t enough compost for everything, the hole was lower than groundline. Soil profile now looked like the attached image (adapted from Toensmeier book).

I then proceed to plant the bare root trees. Out of 50+ only some 2 or 3 didn’t sprout and they’re growing nicely (so far).

But then I came across a passage in Toensmeier’s book stating that: a) when backfilling, it’s important to recreate soil horizons, b) organic matter amendments in holes create anaerobic conditions and (c) encourage roots not to venture outside the planting hole, and d) having roots resting on disturbed soil creates conditions for crown rot (since they settle with watering).

To fix it, I was thinking of digging them out this winter and replant them following Toensmeier’s advice for planting container trees. If their roots are bound to the planting hole, that shouldn’t damage them very much and potentially avoid those dangers. What do you think, could that work?

You could simply plant deep root items (daikon radish as an example) in between the trees, that will start the breaking up of that heavy clay, add some alfalfa and some nitrogen fixers that grow deep roots too. Repeating these plantings and chopping and dropping over the next few years will really improve the clay soil and you wouldn't need to disturb the trees again unless you just wanted to move them. If you made the holes the proper 1/3 larger than the root ball, you won't see any root binding for at least one year of tree growth, by that time daikon radish and other deep rooting plants can provide some air ways for the roots to expand without much trouble.

Great, I planted daikon and alfalfa for that very reason just last week. Good to know I'm on the right track, thanks. But what about water logging and anaerobic conditions?

with the daikon planted, you may not need to worry about water logging, if it seems to be a problem, plant a lot of really thirsty plants, the daikon is a really thirsty radish, so I would check to see before worrying much. You can always sink a piece of pipe and use a stick to check for standing water.

Usually though, once the daikon and other things get going, any water excess problems tend to dissipate as the plants grow. Tomatoes are a great, overlooked, water sucker, one plant can use up to two gallons a day once they are putting off fruits. Watermelon is another fruit that sucks up the water when the fruits set. both of these also put down really deep roots. air going through the daikon and other roots will prevent anaerobic conditions quite a lot. This is one function of roots that is often forgotten about or not known but there is an exchange going on, minerals have to get in somehow and air is one way. If you had not planted the daikon, then there could be more of a problem. At this point it is observe and make adjustments according to the observations. If you create a written record, you can map your progress for future reference.

I planted the daikon just outside the hole, should I seed it inside as well? And would it be good to fill the rest of the hole up to ground level? With what?

Luiz Eduardo Piá de Andrade wrote:I planted the daikon just outside the hole, should I seed it inside as well? And would it be good to fill the rest of the hole up to ground level? With what?

So you're asking whether to fill in the hole from where it's settled around the tree? If so no. Adding in extra soil, assuming it covers the bark of the above ground portion of the trunk can kill the tree (fungus, rot, and whatnot).

I would not plant the daikon in the space you already dug up and planted the tree. I would plant daikon everywhere else, space them around 10" apart so they can grow huge and provide a lot of organic material after you chop and drop them at the end of the growing season. once the daikon are chopped come back with clovers, vetch, buckwheat, peas and anything else you can grow over the winter to chop and drop in the spring before planting the daikon again.

Blake is very right, you can't add dirt or compost around a trunk, when you cover the trunk you are suffocating the tree, and as Blake mentioned, giving bugs and fungi and all manner of other nasty things a place to thrive and invade the tree.
The only time you can do that safely is when the soil has gone down below the planting line that was already established.
The only other time you can do that is if you are growing new roots by scoring and root hormone inducing a trunk to grow more visually appealing looking ground level roots.
This is usually only done to Bonsai Trees since you are in complete control of those trees from roots to growing tips. It is a very specialized, intensively time consuming procedure usually only performed by Bonsai Masters.

If you determine that you need to raise the dirt level, the best thing to do is lift and replace the tree at the proper soil height. Should you not be able to do that, PM me and I will go through the method of growing new soil level main roots, step by step for you.

Aesthetics isn't really very important, as long as it doesn't give the plants any future trouble, I'm ok with keeping them like this, maybe I'll just lift those most sensitive to water logging once they're dormant. But good to know there's a technique for growing roots from the trunk. Many thanks, you've been very helpful.

Luiz Eduardo Piá de Andrade wrote:...But what about water logging and anaerobic conditions?

"Subsoiling" the area around the trees might also be something to try. The aim of subsoiling is to create pockets in the soil to allow deeper infilitration of air (and water). Repeated over time (once or twice a year) it could help create deeper topsoil. It can be done with an impliment (which does not till or turn soil) or perhaps even by hand with a broadfork.

Becky Proske wrote:

Luiz Eduardo Piá de Andrade wrote:...But what about water logging and anaerobic conditions?

"Subsoiling" the area around the trees might also be something to try. The aim of subsoiling is to create pockets in the soil to allow deeper infilitration of air (and water). Repeated over time (once or twice a year) it could help create deeper topsoil. It can be done with an impliment (which does not till or turn soil) or perhaps even by hand with a broadfork.

Is subsoiling with a broadfork the same as double-digging?

Luiz Eduardo Piá de Andrade wrote:

Becky Proske wrote:

Luiz Eduardo Piá de Andrade wrote:...But what about water logging and anaerobic conditions?

"Subsoiling" the area around the trees might also be something to try. The aim of subsoiling is to create pockets in the soil to allow deeper infilitration of air (and water). Repeated over time (once or twice a year) it could help create deeper topsoil. It can be done with an impliment (which does not till or turn soil) or perhaps even by hand with a broadfork.

Is subsoiling with a broadfork the same as double-digging?

More jabbing the fork in and wobbling it back and forth to create air pockets and loosen the soil up. My preferred method anyway, double digging looks like too much work to me!