Here is Richard Hull's article on turfgrass roots

Here is an article on mycorrrhizae (which are roots' best friend)

Just remember:

Roots don’t grow through soil. They grow through gaps between soil particles. By using the deep and infrequent watering technique, you are encouraging the root to grow deeper until they hit what I call the “compaction line”. The screwdriver test can help determine how deep your watering should be.

If you can easily (using 1-2 finger) push a 6 inch screwdriver down into the soil without encountering any resistance, then your grass plants should also be able to go that deep and therefore watering to the point of 6 inches of moisture depth is what you should aim for.

However, if you could only push the screwdriver in about 1 inch, then you should only aim to water to that depth. Anything over that may cause runoff. One method you can do to determine if the ground is compacted or just “hard soil” is by placing a wetting agent (e.g. baby shampoo) into a hose end sprayer and spraying the area at a 1oz/1000 sqft rate. Then water the same area to a 1 inch depth. The wetting agenda may help to “loosen” the soil. The next day, return to the area and see if you can drive the screwdriver deeper.

If you cannot, it’s a good bet that you don’t have hard soil but rather you have compacted soil. Compacted soil may require mechanical intervention, such as core aeration or tilling. This is usually best paired with amending the soil with organic matter, such as compost, to help prevent compaction.

So... just remember: Roots don’t grow through soil. They grow between soil particles.

Becky wrote: Here is an article on mycorrrhizae (which are roots' best friend)

Is it all right if I borrow your corrrhizae Becky? Handy friend to have sounds like. Thanks for those links. Anyhoo I read the other article, and learned a few things, but this is one of those situations where I really need a one armed turfgrass specialist. That article had a lot of "on the one hand..." and "....on the other hand."

I was planning on mowing maybe today but maybe it's better to maintain a little higher cutting height. 80% chance of 1/2" of rain tomorrow. Also want to maybe fertilize and irrigate a Colorado Blue Spruce, we had a rough summer. I know they are drought tolerant but it seems to soak up a lot of nutrients and water surrounding it. Would it be reasonable to say application rates of N can be elevated around or near the drip line areas? Sure seems like it.

Have applied two shampoo treatments and it does seem to help. I take it's a mechanical thing, mostly right? It reduces surface tension in the soil particles leading to less runoff and re-tension? And maybe knocks some of the crud off the leaves etc.

Root growth in cool season occurs when soil temperatures are between 50 and 65F and is absent at temps greater than 80F or below freezing. Fall and Spring. Root growth in the Spring is 30 to 50% greater than that of Fall. Phosphorous is believed to promote root growth. Timing NPK availability with the Fall and Spring periods will promote abundant root, rhizome production.

Water is a lubricant. Compacted or not, Wet soil will always be more susceptible to penetration than dry soil. However, compacted soil will always impede root growth whether wet or not. If you search this site you'll find a number of links regarding commercial wetting agents, shampoos SLS SLES (Sodium laureth), what they can and can't do.