Hi Doc D.!

I can only share the way that I have made 5-1-1 and hope it helps.

I have never used composted bark. Just regular pine bark, bought as bagged mulch that I've chopped up in a pail to get it down to the 3/8" to 1/2" size, then run through a screen to separate the really fine dusty stuff from the coarse usable parts.

Now it's my understanding that the milled peat moss portion of the mix, is in there to give moisture retentiveness. Otherwise, using bark alone, even with perlite, there would be little to no moisture holding capacity.

On the same note, I could've used the bark fines instead of the peat moss and get generally the same results as I would using peat moss.

The dolomite lime only adjusts the mixture ph as the bark and peat tends to be on the acidic side.

One thing to remember, when using a soilless potting media like 5-1-1, is that there are no nutrients in the mix. Any macro or micronutrients, have to be supplied by you and is most often applied in and during the watering regiment, by watering until the liquids run through the mix and out the drain holes in the bottom of the containers. How often depends on the plant type and your discretion.

Otherwise, your plants will be totally nutrient deficient.

p.s. I use a Mirical grow brand of water soluble wide spectrum fertilizer although there are many good brands out there. I also add magnesium sulfate as the MG here in the US doesn't contain any mag.

:-)

One other comment that came to my mind. If you do not flood the pots, so the liquids run out the bottom, you can get a build up of salts from the fertilizers. The flooding and draining not only helps keep the salts moving out of the mix, but also pulls air into the mix along with the water. Roots love air as well as water. ;-)

it should be pretty easy to make composted pine bark for next year.. buy piling couple bags in a tub or in a back corner of the yard.. and composting it this summer ... just steilize it before you put it in your mixes ..

https://tipnut.com/sterilize-soil/

wood steal nitrogen from the soil.. to aid in decomposition ... so the yellowing of the leaves can very simply be a lack of usable nitro.. i would water with half strength water sol fert.. and see if you cant green them up ... or i might go to quarter strength.. and use it with every watering ....

not many of us have a lot of faith in the hand held gizmo sticks for watering.. nor nutrient analysis ..

ken

It really doesn't matter if the bark is composted or not. You can increase the nitrogen a bit if needed, to account for any nitrogen immobilization (according to AL).

https://www.gardenweb.com/discussions/1610475/partially-composted-bark#n=2

And bark is not the same as wood and doesn't decompose at as fast of a rate like wood, or immobilize the nitrogen at as high of a scale like wood products do.

I used to pick out as much of the wood product as possible for that reason.

..... and it needn't be "sterilized", either.

I regularly use uncomposted (raw) bark.

Keep in mind that the pH of container media should be lower than whatever pH is suggested for a plant in mineral soil. IOW, if a plant label says the plant prefers a pH of 6.0 - 6-5, unless noted it should be assumed to mean 'in mineral soils'. In contrast, a plant preferring a pH of 6-0- 6.5 in a mineral soil will need a pH of about 5.2 - 5.7 in a container substrate. This is one of the reasons coir and CHC's need to have a workaround in place (due to their high pH) other than a liming agent as a Ca/Mg source.

Al