In general its best not to add Organic Material to the planting hole when planting trees and shrubs. The opposite is true for vegetable gardens.

If one adds organic matter, compost and other stuff, once and then goes away and leaves those plants on their own then spending time amending the soil is a waste of time, energy, and maybe money because those organic soil amnedments must be continuously replenished. Too much organic matter can be added to soils, optimum is between 5 and 8 percent organic matter, because too much organic matter can create a bog, a swamp. If someone wants to create a wet land what are they told to do if the water table is not high in that area?
Like any other generalization statements like "In general its best not to add Organic Material to the planting hole" mean nothing because it depends. If you have an unamended clay soil that does not drain at all well then adding organic matter to the planting hole can create a tub where water accumulates and cannot drain out. However, if your soil is really quickly draining sand not adding organic matter to the planting hole can cause what you plant, tree, shrub, flowering plants, or vegetables, to not have enoughj water available for growth and that plant will then die.
Since mulches are meant to aid in retaining soil moisture levels laying mulches on clay soils that do not drain could create conditions where too much water is help in that soil and the plants rot. Rather then hold to rigid rules think about what could happen and what might need be done to prevent problems. Appy common sense.

I've been gardening in clay soil for decades and the clay we have here is so heavy that most plants don't survive if planted directly in it without amending. So initially the entire area was lightly amended and subsequently I've further amended each planting hole. I also add compost to some part of the garden every year but never have enough. What has happened is that there are now lots of earthworms in every part of my garden, even where the soil is still heavy and hasn't been amended much. They have improved the soil for me so it's getting better every year in all areas. I've deliberately not used my precious compost in some beds where there are tough plants but water all the plants with alfalfa tea which I believe also encourages the worms.

I know it's daunting when starting to garden in heavy clay soil but clay soil once amended is better than many other types as it holds moisture and has minerals that plants need. Try every type of composting/soil amending that sounds do-able for you and you will notice a great improvement over time.

I've been gardening in this soil for 15 years. Most of the planting was done by digging a hole, adding amendment, and keeping the area mulched. About 10 years ago, we created a new bed beneath a tree using the sheet composting method; the lawn sprinklers kept the layers damp and there were lots of worms when I planted that fall.

I decided to use the same method to improve these beds in our side yard because it worked so well in the front yard. However, that area beneath the tree had sod prior to the perennial bed, and was already somewhat cultivated and regularly watered with the lawn sprinklers. These beds in the side yard were bone-dry raw clay on which we'd walked for the past several years. Hedges grew in them until we removed everything in the side yard about 10 years ago to start over. It's more difficult to keep these layers moist because they get a lot of sun during the day.

Anyway, I'll try to not worry too much --- the articles at that site are very interesting but last night I worried that I've done everything wrong and all my plants will keel over and die because I added amendment to the hole at planting time. I've seen worms all over the back yard, even in open areas that I haven't mulched the past year.

I wish I'd done a soil sample prior to creating these new beds, but I could sample some of the soil next to them. Or just keep doing what I've been doing for 15 years and listen to the plants which seem quite happy! :)

g'day jenn,

sorry didn't read the links you provided, no going to. so i'll go on the tone of your post.

i do not believe that you can overdose soil or growing medium with organic matter of any sort, especially in sheet mulch format, our raised beds are an exension of that method.

the worms and micro-organisms will work the organic matter at their pace, as i see it. check our straw bale garden presentation that is all organic matter and the plants love it.

knew a bloke who had very poor soil, just over an acre, he started a program of sheet mulching using mushroom compost and spant hay, he was steadily but surely improving all of the soil as he worked it in that manner, a lot of work but in the end a geat result. he had no internet he did no research he simply used common sense.

don't take this as personal because it isn't we need to get back to KISS (keep it simple stupid/silly), we need to get back to natures natural ways, no scientific hum drum how do you think the habitat survives so well on its own? well until the greed of man comes along and clears it, and the fragile topsoil nature created for all those centuries gets eroded away.

we have a fruit tree garden mostly citrus we never water it, we never feed the plants, hardly ever prune them they are all loaded with fruit a seedling lemon with fruit as large as a good sized grape fruit, a navel orange with fruit the size of an average grapefruit, an imperial lemon with fruit twice the size of what the shops have, all trees are loaded probably over loaded. the treeslook great lush and green.

what did we do to create the area? and what do we continue to do in that area? we use sheet mulching of sorts, that's it natural and too easy. over 5 years we have created about 2-3"s of humus and ammended about 2"s of the original soil to humas status and it goes deeper, oodles of worms. we started with clay. when we prune we drop it where it is pruned and cover it with mulch.

len

Here is a link that might be useful: lens straw bale garden

Professor Chalker-Scotts second article ends with
"� Ideal soils, from a fertility standpoint, are generally defined as containing no more than 5% OM
by weight or 10% by volume
� Before you add organic amendments to your garden, have your soil tested to determine its OM
content and nutrient levels
� Be conservative with organic amendments; add only what is necessary to correct deficiencies and
maintain OM at ideal levels
� Do not incorporate organic amendments into landscapes destined for permanent installations;
topdress with mulch instead
� Abnormally high levels of nutrients can have negative effects on plant and soil health
� Any nutrients not immediately utilized by microbes or plants contribute to non-point source
pollution"
Which is pretty much the same thing I have been telling people here for quite some time. Some years back some garden writers strongly suggested adding very large amounts of Organic matter as well as pouring tons of rock dusts, etc. on yuour garden to build up soil fertility, and some people still adhere to that. But today many people know that too much organic matter and fertilizer simply helps pollute the ground water with that excess which will flow out of the soil with water.
Work toward balance in your soil, not toward excess.

kimmsr - Thank you, but that doesn't answer the questions in my original post. Am I wasting my time building these layers in preparation for late fall planting of perennials and shrubs? Or would the materials be better used to create a large compost pile which can cook while I take samples of the soil (now beneath newspaper at the bottom of about 6" of OM) to get it tested..... then, plant directly into the clay in late fall and top dress with a thick mulch?

I understand that what I read in the article is true.... I'm wondering if these layers (which will require quite a bit of water to say moist through summer) are a waste of my time and if there's a better way of doing this.

Perhaps a better question is: Should I change course now? It's not too late... I won't be planting until late fall, at least 6 months away.

in a word sheet mulching is not a waste of time.

len

Hi Jenn,
You tell us (next year ;-)
This is how we all learn, we try something and if it works we teach others how we did it and what we did and what could have been changed to create even better results....or... we teach what didn't work, what failed ,why we think it failed and what we would do differently. We are all learning and growing every day, everything doesn't succeed ,but many things do, I say try it and then come back and teach it...
BTW... I am not of the majority on the "you can have too much compost....theory"
I do start my beds with approx. 25% Compost,25% Clay,25% Decomposed Granite and 25% Pumice, but after the initial bed is built ,I never add any ingredient except finished compost, I pile it on...deep, and it is absolutely luxurious, it is the most awesome soil on this planet, I am soooo blessed.

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Yes, its definitely worth while, particularly when starting off a new bed. Later, when the plants are well established, then the compost mulch keeps the whole thing going.

Thanks guys! I decided today to keep them going, but it's going to get tougher to keep them damp when the temps heat up.

I'm planning to stick some bush bean seeds and Sunflower seeds in the piles and see what happens... if they fail then I lose nothing but a few cents per seed, but if they succeed then I'll get a little help from their roots.

Adding organic matter to soil is always beneficial, as long as you do not add too much.
The only way to know what the nutrient level in your soil is with a soil test and best is a soil test from a good soil testing laboratory and not a cheap home soil testing kit, you do get what you pay for.

Both those articles refer to trees and shrubs and those have been the suggested practices for those plants for years. It's a different thing for annuals and vegetables so incorporating compost into the soil when planting is fine.

I'd leave the sheet composting there and in the fall, pull it back and plant in the native soil. Then each year you can compost around the plants or use some kind of mulch to keep the soil from eroding.

The sheet composting should have composted quite a bit by fall and it should be a good mulch for the winter. Meanwhile any earthworms and soil microbes will be happily making that bit of earth much nicer than it was.

keep seeing about o/ding soil on mulch in my case it hasn't happened yet and not likely to, no science needed just immitate nature, nature does not need science to tell it what to do, in nature it handles an decomposes what ever amounts of material comes along.

do your sheet mulch you will be streets ahead.

len

Re "too much" organic matter.

If on the one hand, one can grow plants in containers in pure compost, and I've grown an entire garden in pure, composted horse manure, how can you have too much organic matter?

PHD or not Scott is wrong on much of what she said. You should work up 4 square feet of soil for fruit trees & go at least 12-24 inches deep.
I have planted burlap ball trees, potted trees, even dug them out of the woods & replanted them.
I have never used more then 1/4 amendments in any hole, but think it is important to spread the amendments out over the 4 feet square.
This has worked for me & I will stay with it, no matter how many papers are published for a University.
Some of what she says is for bare root (hill in hole for roots), not burlap or potted plants. Yet she does not say that.

jolj: I suspect the articles are intended to present the ideal approach and scientific basis for each one, or to educate home gardeners who use the refuted methods without questioning "why" they're done and struggle with repeated failures.

It reminds me of when I first began gardening many years ago and was trying to grow some plants from seed. I carefully followed the instructions to the letter: Sow on top of vermiculite in little peat pots, water only from below, set out and harden off when all danger of frost is past, blah blah. Then, I noticed spontaneous seedlings coming up in the garden and in pots I'd forgotten to water, and I thought "Hmmmm... they're not planted in vermiculite, watered from below, set out after frost, blah blah!" LOL

For those that think there can never be too much organic matter in soils have you ever been in a swamp, bog, fen? Ever tasted the water from a swamp, bog, or fen? Ever smelled water that came from a swamp, bog, or fen? That offtaste and smell comes from pollution of the water caused by too much organic matter in the soil there and it is not good for you.

Kimm,
That was stupid ;-(
You ever heard of the Dead Sea ????
Apparently, your argument would suggest large bodies of water are bad , and you use that(Dead Sea) example to prove it....
Reality Check....
Dead Sea has no outlet, that is why it is dead (well...kinda dead)...
But ALL of the other large bodies of water on the planet are just fine (they have outlets... OY VEY)

As David said "If on the one hand, one can grow plants in containers in pure compost, and I've grown an entire garden in pure, composted horse manure, how can you have too much organic matter? "

and I think he was quoting YOU, on the first part of his post....

You said you grow in pure compost pots, and you said your plants grow fine there...

But, I am sure those pots also have outlets.... OY

Yup. I was curious on the seeming contradiction.

In containers plants can, and do, grow in compost and containers are different then in the ground and that large amount of organic matter in containers is not going to flow with the rain into the ground water. The Dead Sea is not an apt comparison to a swamp, bog, or fen.

Joli said:

"PHD or not Scott is wrong on much of what she said. You should work up 4 square feet of soil for fruit trees & go at least 12-24 inches deep.
I have planted burlap ball trees, potted trees, even dug them out of the woods & replanted them.
I have never used more then 1/4 amendments in any hole, but think it is important to spread the amendments out over the 4 feet square.
This has worked for me & I will stay with it, no matter how many papers are published for a University.
Some of what she says is for bare root (hill in hole for roots), not burlap or potted plants. Yet she does not say that."

Exactly correct IMHO. Scott is one of those people who likes to convince us that the sky isn't blue on a sunny day so to speak. She has made a living by being a contrarian.

There is absolutely nothing wrong with layering your soil with organic matter. In fact, in the VAST majority of cases it is VERY beneficial. Period...end of story.

Sure, don't go crazy with amending the planting hole soil for permanent plantings, but that is common sense.

You seem to be doing FINE......keep it up IMHO.

hardly see that a swamp has any relationship to a garden really, come smell my organic o/d'd gardens they smell like gardens and obviously the fruit trees love it.

len