Unit for unit (other than possibly clay) OM is going to hold more moisture than any soil amendment. More OM, higher soil water content.

Wouldn't the OM lighten up the soil at least so it does not compact as much to help aid in *drying*

Yes, it will. Adding organic matter to the soil is the preferred method by far to loosen a heavy clay soil and to improve drainage. The coarser the OM, the better the drainage. All OM will retain moisture - that's just the nature of the beast - but as long as drainage is fast, the bulbs should be OK.

Personally, I'd use a coarse bark. And some bulb fertilizer/bloodmeal when planting them to offset any N tie-up from the bark.

if you put digestible OM on top, the earthworms will make some channels. Mostly in the first two inches though, although they go below the frost line in winter. then there is a technique which is biology friendly and makes channels to 3 feet and more, which the worms will actually follow and open further. No prizes for guessing which.

" there is a technique which is biology friendly and makes channels to 3 feet and more, which the worms will actually follow and open further. No prizes for guessing which."

Do share. I asked my local barista to save me a stash of his UCG. Threw a pile on last night and man, slugs really hate that stuff. The only evidence of their midnight evacuation was the slimey trail that was not there until the UCG mountain was added yesterday.

Glib standard advice is to plant cover crops that put deep roots down. (Do I win that prize?) Seems reasonable to me in this instance. Regardless, adding organic material won't make your drainage worse and will probably help. But maybe more info on your soil and drainage would help us understand. Is it pooling or just damp, for example. Some sogginess of soil as snow melts is pretty normal - planted areas with roots seem to have less of this, though; plants certainly take up some water.

Hugelkulture?

The problem with waterlogged soil is not actually the water itself, but that the water displaces the air that would normally be in the pores in the soil. Without oxygen in the soil, plant roots cannot respire (i.e. use oxygen in the generation of energy) and the roots cannot function. (Aquatic plants have special adaptations to get around this problem)

The reason that organic matter in the soil can improve over-wet conditions is that the organic matter tends to bind together the soil into aggregates or "granules" which are uneven in shape, leaving more air pockets between them. Organic matter in the soil also provides food for worms and other soil critters that help aerate the soil with their tunnels and channels.

This all helps up to a point, but won't solve a more severe water accumulation problem. So armoured's question is crucial - does the area just have occasional /seasonal dampness or is it chronically boggy, or somewhere in between? The seasonal compaction from spring melt is something that better organic content in the soil could help with. If you are unsure of what the organic matter percentage is in the soil, you could get a soil test for that area.

Previously, it was a full bed of iris. When I dug it out, it was a neglected area of full on iris bulbs/rhizomes. When it was all culled out, the soil was sandy/dry as heck. Almost powdery. Tilled it with a good heapload of UCG. The soil was lifeless.

It was nice and airy post tilling until it rained and the soil stayed wet for days and compacted back down. I just want to get the soil to get to a state where it dries out better - got a huge order of bulbs coming in late fall. Then I'll probably plant some low water Vinca's in there once the blooms have faded.

Last thing I want is just have these bulbs rot..

Back to OM. I'm thinkin just to speed up adding OM to the soil, instead of mulching, maybe mix in the very top layer with Pine Bark into the soil so it breaks down faster ----no chipper on hand ;-0

That's what I assumed. So to recap: You added OM (UCG) and afterwards judge the soil as too wet. So the cure is to add more OM. That logical? :)

I added UCG after the 1st rainfall and seeing how it compacted -. Added the UCG figuring figuring that was a easy OGM that I could get from my local guy and it would add some nutrients into the soil

So the question goes then, if the soil compacts easily when wet, stays wet even in late summer - 70F for days on it, would additional OM at least give the top layer a better density to dry out ?

So what's the consensus. If OM is not the answer it adds even more moisture.....how does one get wet compacted soil to dry out and let air in....

It is the texture and size of the OM that makes a difference. UCG's are simply too fine a particle size to make any meaningful contribution unless applied by the truckload!! You want larger, chunkier material that is less likely to breakdown rapidly.......bark or wood chips.

Besides the UCG, what else have you done? How thick or how much (lbs) did you add? How big is the area?

Edited out the till question as I missed your previous post.

Tilled in the UCG but not much into the top. Due to the compactness, spread it with a rake and some high swings with the rake so the tines would get into the soil and just tilled in what came loose. If I was not lazy, I would have used a fork but figuered I'll be back removing it soon anyhow. I'll be breaking up the bed again in 3 weeks or so when the bulbs come in . When I dig out the beds again for the bulbs, that's when whatever next course of action is re: amending or not, will be incorporated in. Area is 20 feet long x 2 wide.

Trying to visualize your soil.

>>the soil was sandy/dry as heck. Almost powdery.

I'm familiar with that kind of soil, sometimes it is actually hydrophobic (water runs off). We see complaints about that here sometimes.

You said that it compacted back down after tilling in UCG followed by rain. Sand doesn't compact so this must have some finer particles in it. What made you think it was compacted?

If it is sandy or even silty, it should drain, so why does it not? Which leads me to 'how deep does this type of soil go, and what's underneath it?'

Looks like we cross posted there.

I would add: it may take some time for the texture and behavior to change. You may have to be patient and trust that amending it with OM is going to improve it. As long as you've eliminated other factors like availability of drainage.

Thanks. Sounds like the problem is that you've just created an insulating blanket of high moisture retention OM soil. Easily cured by incorporating into a greater depth (4-6"). BTW how much UCG did you apply?

I echo gardengal's comment: UCG is too fine to have helped much. If it was very sandy and powdery, it sounds like it has relatively little soil life or humus in it. It needs stuff in it that lives and creates/excretes the things that hold the soil together, like mushroom hyphae, wee bugs and critters, etc. These will create the soil aggregates (clumps of soil, but clumps may be micro-size) and tilth that helps a handful of soil stick together when you squeeze it.

So basically: lots of organic matter, compost, lumpy stuff is fine. You can bury all sorts of stuff (trench composting) and let the soil food web take care of that. Even burying wood and wood chips and whatnot will work. Since you have a winter, bung that stuff in the ground before winter. Mulch on top, too.

Two caveats: this may not work perfectly in the timeframe you're hoping for, i.e. getting bulbs in good soil to grow next spring. But it'll work eventually. Second, if you put a lot of wood or wood chips in the ground, it may require some extra fertilizer (nitrogen in its many variants, bloodmeal, etc).

Tox : re your comment about hydrophobic.

The soil that is adjacent but not where I dug up - shrubs, etc - all nice and healthy.

Granted, I specifically have avoided watering this area knowing it was going to get a full on rip/replace this time of the year. Due to the density of the iris bulbs/rhizome/root that was so super dense in this area, I do think that water to quite some degree did somewhat ~roll off~ on this area. Underneath, I'm fairly certain there is some clayish properties that I might have incorporated more when I tilled it. Ehh, it was like I was uncovering a desert when I removed the iris's.

So 2 fold, It was dry as heck, I tilled about 8 inches in. Then it looked wet as hell after rain, and remained wet.

RR. The UCG when spread was not much in the grand scheme of things. Maybe about 1/4 thick at most.

I'm thinking about putting in bark mulch. incorporated just in the top layer. I know the mini bark nugs. should break down considerably by spring, but if it's just in the top layer, it's manageable to remove easily if it gets too wet.

And or should I go all in, and incorporate the bark a good 3-4 inches in the top layer.......basically a good ratio or bark/soil when I topdress the bulbs back in.

"Tilled in the UCG but not much into the top. Due to the compactness,
spread it with a rake and some high swings with the rake so the tines
would get into the soil and just tilled in what came loose. If I was not
lazy, I would have used a fork but figuered I'll be back removing it
soon anyhow."

" It was dry as heck, I tilled about 8 inches in."

Sorry, I'm lost. Good luck.

If it's powdery, you need to lay off the tilling/digging/raking, as that will further pulverize it. I agree that it's maybe too ambitious to think you can really fix this soil in the next three weeks.

There is an important difference between wood chips and bark chips. Bark is much slower to break down, and in fact it contains some hydrophobic substances itself. So it would likely be counter-productive to use bark mulch on this area and definitely would not be a good idea to mix it into the soil.

I would consider a good layer of compost over the surface of the soil, and a couple inches thick layer of wood chips, not bark chips, over that. And then leave it be over the winter.

Where are you? Anywhere near me, bearded iris require excellent drainage. However, if you are digging out a lot of them, you may have dug a pond. So any water from the surrounding area drains into the bed. Adding organic matter doesn't help because it isn't a drainage problem, but a grading problem.

BTW, a tiller is the wrong tool, as you have found. They just can't get deep enough to do any good.

yes indeed. Cover crops fix the problem, unless you have a really hard pan somewhere, but they take time. Hugelkultur is next best, but it takes energy. Vertical hugelkultur (where the logs are buried vertically) performs better on most fertility parameters and obviously will drain better the OP's site but it is more work to dig manually at that depth compared to regular hugelkultur. Unless you have a tractor and a post digger. being lazy, I prefer the time-consuming solution.

We had a whole discussion recently in which it was asserted and agreed to by many (if not most) in the thread that double-digging was a good thing and that it takes a long time to get organic matter and its beneficial effects very deep if you're only amending the top. It was so convincing that I vowed to double dig the next time I started a new bed in poor soil. Here, we have suggestions to just mulch it with compost and wood chips. ??

Why not dig or till compost (and/or ramial wood chips) into this area very deeply so the aggregating processes that improve soil texture can get going faster? Assuming the OP wants faster, and that deep-rooted cover crops can also be used regardless.

That was not my intent :-) Unless you have a lot more time to wait for things to happen than I do, tilling the OM into the soil is SOP!! Eventually, just mulching or top dressing with the OM will have benefits but it will take multiple growing seasons.

And planting deep root cover crops makes no sense when planting spring flowering bulbs.......they will not play well together :-)

I would suggest getting a shovel down at least in one area - a foot or two - to see what's further down. But it does sound more like the soil here is just different because of what you had there before. I'd say digging it up some and adding organic material is still the most likely fix.

Where in the world are you? Zone 7b only tells use about plants should survive the winter where you are and tells us nothing about the soil you have, potential rainfall, or anything else needed to really answer your question.

What type of soil do you have? Clay? Sand? Loam?

Is a high water table a possibility?

Here is a link to a soil taxonomy map if it helps, just click to zoom in on your place. It starts with a satellite viewpoint.

http://www.arcgis.com/home/webmap/viewer.html?webmap=0edea1c7bbb84ba5842d20483af11679

hello,

it's me again. as I get closer to planting time, let's formulate a plan. On the beds I plan to dig out (for the bulbs), the final top 5 inches will look as such. 1 inch mulch on the very top, 4 inches of soil with mulch and compost tilled in.

Riddle me this as I don't really use ferts much, except for the vegs and roses.

I DO however always sprinkle a dash of super phosphate and biotone if I'm putting something into a hole....

Under the bulbs, I do plan to add some super phosphate.

Picked up some bulb food as well. What is the effect of ferts if I plant it 1 inch above the bulbs as opposed to if I apply the ferts in the upper part of the topsoil.'

AKA, if it's in the upper 1" of the soil, is the delivery just delayed as it needs to reach the roots. Granted, organic ferts are slow and the microbes need to do their work, etc....Any benefit or difference is one puts ferts in the upper part of the topsoil or the lower ~part~ that is closer towards the bulbs given the ~tilled mix~.

The bulbs already have the stored energy for blossoms. Just wanted to add some ferts due to the tilling of the mulch

Bulbs are in OT, but ever have that @##@! reaction when you prepped a bed. I double dug and filled up about 18 contractor style *rice bags*, aka, the heavy weave type filled with rocks galore. Who ever know so many rocks one would uncover when you double dig.

I was like a archaeologist / paleothologist . I slowly used a hand shovel to find each large rock. 2 years ago, I went to plant a shrub, with my metal shovel and 1 foot doward heave into the dirt. Hit a rock that vibrated/ricocheted back into my leg and caused something in the leg to reciprocate, as I was limping for almost 1 1/2 months, with leg pain for the whole 45 days.