I often use 100% pine bark soil conditioner in my large whiskey barrel containers. I don't screen, but almost all of the product is less than 1/4" and around 10% will pass through insect screen. This "mix" is certainly less than ideal, but performs adequately for my tomatoes and annual flowers.

I don't use the soil more than one growing season as rapid breakdown and compaction will begin to occur after that time. The spent soil is useful as a mulch or soil conditioner.

As JD alluded to, you can do almost anything you want, and with a little effort, MAKE it work.

On a per volume basis, perlite and peat aren't that much more expensive than the bark, unless you get the bark free; so if you need a fair volume of soil the expense of a 4 cu ft bag of perlite and a big bale of peat isn't that great.

In peat based soils, perlite mainly serves to reduce water retention. It really doesn't improve drainage/aeration much because the fine particles of peat simply filter in between and pack around the perlite particles; but in pine bark based soils, perlite DOES increase aeration and drainage, by virtue of the fact it gets wedged between the flat bark pieces, creating macro-pores and opening channels through which water flows easily.

Hopefully, you'll be able to see your way clear to at least get the perlite, if not the peat. I think it will make a significant difference.

Al

Here is how the bark breaks down size wise after screening through different size hardware cloth.

12% of the bark is - 1/4" to 3/8". used 1/4" hardware cloth to screen bark.

36% of the bark is - 1/8" to 1/4". used 1/8" hardware cloth to screen bark that remained from above screening.

32% of the bark is - window screen to 1/8". used window screen to screen bark that remained from above screening.

20% - amount that passed through the window screen.

If I compromise and use perlite but not peat, how would the 5-1-1 mix be made using the above size pine bark fines with the perlite?

Thanks

Part of your reluctance to buy perlite may be due to the ridiculous prices of the small bags you see at the box stores. The 4 cu. ft. bags are usually only found at independent nurseries in my area. I still pay $30 for 4 cu. ft. of perlite, whereas pine bark can be had for $1 per cu. ft.

I should add that my whiskey barrel containers have huge drain holes and sit on well drained soil. Some of the container soil is in contact with the earth below. This leads to a natural wicking effect that helps balance the less than ideal drainage of a 100% bark mix. Including perlite does lead to noticeably positive effects in all my other containers with a 5-1-1 type mix.

I strongly recommend adding Perlite.

Bark will hold an excess amount of moisture and will dry differentially throughout the layers.
By itself, it is not an optimal medium. With the simple addition of Perlite, I've grown healthy
maples (for a season), as well as a fig tree, willows, osage, and few others I'm not remembering.

Hydroponic shops usually carry large bags of coarse Perlite. I buy 4 cu. ft. for $20.

Josh

Joe....I told you about Elixson....did you go with the bagged product or the bulk?.....I laughed when he said "....with a big enough trailer it's $10 a cubic yard..."

I agree with Josh about the Hydro stores....Florida abounds with them....I still pay less than $20 a bag for Perlite.

Why are you screening ?

These are Vegetables...I've taken a simpler approach...I don't screen...I don't add peat...5-0-1 ?

To each Bag of PBF I add 3 gal of perlite and about 2 cups of lime (powder) and a small cup of CRF....This year I got a tumbler/composter.....Oh so nice and fluffy....what a pretty end product....I have never got the lime blended with the bark as well.....

and

THANK YOU Al....for the Education, Patience, and Friendship.

doug

Thanks ya'll, guess I'll try to find a 4cf bag of perlite.

Abnorm, I did get 2 cubic yards of pine bark fines from Elixson in Starke. They have quite a large operation there. I was expecting a small mom and pop type business so I was impressed to see the mountains of pine bark scattered over several acres and all of the heavy equipment thay have to grind and move the material around.

I screened the bark mostly out of curiosity to see how much of what size there was. It's all usable so there is really no need to screen. Nothing too big to screen out.

With 50% passing through a 1/8" screen, I figured that small size could replace the peat.

"If I compromise and use perlite but not peat, how would the 5-1-1 mix be made using the above size pine bark fines with the perlite?"

I would make the bulk of the "5" portion from the 1/8" - 3/8" range, with anywhere from 1/2 to 1 part of that made from the Window Screen - 1/8" range.

For the "peat fraction", I would use 1/2 to 1 part of the Window Screen to Dust range.

I would use 1 part course perlite (window screen and up). I personlly break down my perlite into ranges, to ensure I get a 50/50 mix of particles greater and less than 1/8". Not necessary, it's just my preference.

"It's all usable so there is really no need to screen."

I personally think that it is important to screen. If you don't, you are guaranteed to have varying compositions from mix to mix because your bark will vary from batch to batch. I don't like that. I want to know exactly whats in each mix, and I want the ability to adjust the characteristics to my liking.

PJ

Well said, PJ!

Josh

Your analysis looks good, thanks for the help.
I'm looking for the 4 cf bags of course perlite, when I find that I'll be good to go.

Getting back to screening the perlite.

I'm a bit confused. You say to use coarse which you say is window screen and up size. Then you say a 50/50 mix with 50% below 1/8" and 50% over 1/8".
Can you unconfuse me??
Thanks

Joe, where are you located?
I would recommend you use Perlite that is larger than what passes through window-screen.

PJ is growing in Florida, and so his personal preference is a mix that retains more moisture
in the heat (PJ, correct me if I'm wrong on that!).

Josh

I'm in north Florida, plenty hot here too.

Sorry for the delay...and for the confusion! Let me try this again.

"I'm a bit confused. You say to use coarse which you say is window screen and up size. Then you say a 50/50 mix with 50% below 1/8" and 50% over 1/8"."

Everything that I use is sized greater than window screen. Remember, window screen is 1/16". My preference is that I pass the perlite through a 1/8" mesh first, then pass that through the window screen. What passes the window screen gets discarded. I then use 1/2 part > 1/8" and 1/2 part "Well said, PJ!"

Thanks Josh! I learned from the best =)

PJ

Thanks for clarifying that. Next is finding the perlite in large affordable bags.

Thanks for the help.