Also, it is not clear whether Al refers to pine bark fines that are screened or not. That, of course, would decrease the ratios even more.

Glad I'm not the only one confused by this! I just figured I was an idiot somehow...

As long as you do your own measuring and keep the ratio to approx 5-1-1 as a starting point you should be fine. In my case this year, I found some nice soil conditioner that was usable right out of the bag as pine fines, but it was a little too fine, so I cut back on the peat in the mix so it wouldn't retain too much water.

the math doesn't add up to 5:1:1 curious what others have to say. I did recently use the big batch formula (trying to make 3:1:1)

I think pbf screening depends on the quality of the product. Al does state his preferred size.

Pbf smaller than 0.10 inch will raise the PWT, which shifts the batch to having more water retention but less aeration.

it's unclear to me what disadvantage (if any) for having pine bark that is larger than desired.

I do believe the pine fines are supposed to be screened to 1/8 - 3/8" in size. I think the occasional larger piece won't hurt but if there's too many it'll disrupt the structure of medium (I'm thinking). It's best to keep it what Al recommends I imagine.

okay, so at least I know I'm not loosing my mind :)

the ratio is probably a guideline and you get a feel for it or something.

You might want to screen the pine bark to maintain consistency from one batch to batch because the proportion of fines varies with manufacturer, product lot and age of pine bark.

Dust to 3/8" or 1/2" is ok. The major concern for me is how much water retention there is. If there seems to be a lot of fine particles, I can cut back on the peat.

That's right. It's commonly discussed that the bark fines do not need screening, other than to eliminate large bark pieces over 1/2.

Josh

did anyone figure out why the numbers seemingly don't add up to 5-1-1?

Don't sweat the exact ratios too much. 5-1-1 is a catchall that MOST plants will do well in.

I go by how it looks/feels, and have several 5-1-1 mixes modified for particular plants water preferences. I grow 'Black and Blue' salvia for the hummingbirds and added 2 peat, skip the pearlite and added NAPA 8822 because 'B&B' likes more water. I use Miracle Grow straight from the bag with the pot sitting in a deep saucer kept full of water for my Cardinal Lobelia because it flowers better in boggy soil. Cuphea, and most others like 5-1-1 by the book.

It helps to have extra ingredients, so you can modify if need be. I found a soil conditioner (pine fines and "forest products") that was perfect...well it was last year. This year the same brand was a bit peaty, so I had to add additional pine bark mulch to compensate.

I would suggest making small batches and experiment until you get the hang of the look/feel of 5-1-1 and your particular plants. and I don't sift for 5-1-1...too much work!

I agree, the 5-1-1 is a good starting point. I usually make adjustments to make up for the water retention I need. Sometimes I'll add more or less peat depending on how fine the pine bark is.

just noticed one of the other threads discussing 5-1-1 also mentions 3-1-1.

makes me wonder if the recipe really is for 3-1-1?

http://forums2.gardenweb.com/discussions/1378483/taplas-5-1-1-container-mix-in-more-detail?n=118

It might be easier for some to think of the recipe as 70% bark, 15% perlite, 15% peat (or peat substitute).

When I make a batch to fill multiple containers, I literally line up my containers, then take a bag of bark and go along the line filling up each container to approximately the 3/4 mark (which allows for settling of the ingredients). Then I add perlite to fill up half the remaining space, followed by potting mix. Then I dump the containers into a wheelbarrow or onto a tarp, and mix thoroughly. That's when I add Lime and Osmocote.

Josh

Andi, If memory serves, that was a typo that was pointed out and corrected on later incarnations of the thread.

That being said, I have successfully used 3-1-1 with on plants that preferred more water and were more tolerant of "wet feet"

Interesting, never thought of doing the calculations and so did not notice the discrepancy. I sort of do what Josh does except I use a 5 gallon and 1 gallon buckets for measure and fill one of those saved mulch/bark bags. Add lime and some water in the bag and mix it in the bag by shaking it. I store several of those 7 gallon bags in the shed and let it "rest". In fact, I will have to do few other bags soon.