Vertical Mulching With Biosolids To Improve Clay Soil Conditions - March 2023

Over the past week or so, I've been working on - and posting about - the front yard beds.  Mostly, I've been working on - and thinking about the soil conditions.  Since we moved in - Summer of 2017 - I haven't had much luck at all up there.  That's six growing seasons (well...five full ones at least) and I've lost things, have had other things not grow so well and removed the biggest plant in this bed last Fall:  the large Norway Maple tree.  

I started last week doing some vertical boring of holes using my post hole digger.  Both, to get a real look at the soil conditions, understand how deep the clay lies under the topsoil and to (maybe?) help improve the conditions by cutting through some of that bathtub effect that takes place in clay soils.  After I dug a hole about 12" around and 24-or-so-inches deep, I proceeded to fill it up with some leaves and a big helping of biosolids to top it off.  My thought is that this 'vertical mulching' will improve the soil in spots and provide a deep refresh of organic material to help deal with the clay conditions. 

Yesterday, I posted about how I'm dealing with a deep layer of stump grindings in this bed and how I've used some biosolids to attempt to 'balance' the situation both on TOP of the bed and mixed in closer to the new tree.  

Over the past few days, I've gone out and dug even more holes.  I count twelve (currently) open ones plus the one I already filled.  That's 13 holes so far.  

Here's one up on top of the stump grindings - showing what that soil looks like right now:  some decomposition, but plenty of wood in there:

I dug a few of these deep holes near where the spot where I lost one of the Hydrangeas and behind some of the boxwoods.  Below are a few photos showing these holes:

What do they look like?  Here's a peek down the hole.  Thanks to the mulching, it seems like I have a good six-inches of organic material before getting to the clay.  See below.  You can also see those fine roots that were (I think) from the Norway Maple that created that ROOT MAT in the soil:

Below is another photo showing that root mat cross-section from the hole.  Chopping through the root mat in these spots *HAS* to help with the situation, right? 

I also dug even more holes around/near the very first one - in the front of the border.  This area has never been a rich, humus-y area.  So, I wanted to aerate in spots.  I ran some holes both along the front of the border and along the stoop.  See below:

What happens next?  First, I'm going to dig a few more holes.  Then...I'm planning to stuff as much leaf litter as I can in these - I'm going to pull from the Disneyland Roses to do that.  Finally, I'll top them all off with biosolids.  I can't get the organic material into the ground soon enough. 

After that?  A proper bed expansion - with a new front border, some new shrubs and a plan for annuals.