can very fine pine bark be a good substitute for peat?
Yes. Fafard makes a finely ground, partially composted pine bark product that is uniform in size (their 'aged pine bark fines') and too fine to be suitable as the primary fraction of any soil you're looking to take advantage of for it's superior aeration and drainage. That product would make a good peat substitute.
can you give me some idea of the size of fine pine bark that would be suitable as a replacement for peat? i can buy pretty fine bark, most is less than 3/8", in bulk at a far lower price than peat so i'd rather use the bark if it is doable, i can't afford the peat along with the other ingredients.
btw Al, i did make a raised bed using topsoil, pine bark, and compost, based on your recommendations, and that worked out great for the winter crops that i planted.
In the past, I have kept the fine bark dust that I screened in a separate container.
This bark is basically anything from dust, up to 1/16 of an inch...nearly the same particle size as peat.
I have used it in fern mixes, in particular, when I wanted to increase moisture retention without using
peat. Even at this small size, bark is still more durable than peat. Two thumbs up!
looks like what i can get will work just fine as a substitute for the peat. now if i could find an inexpensive substitute for vermiculite i'd be all set.
Sure thing, Joe.
So, why are you looking for a vermiculite substitute?
I guess I should have asked what sort of a mix you're putting together.
I'm trying different mixes for raised beds and want to make something similar to "Mel's" mix which is 1/3 compost, 1/3 peat, and 1/3 vermiculite. I just can't afford those ingredients so looking for substitutes that are affordable. So far I use compost that I make myself, and the pine fines I can get pretty darn cheap in cubic yard bulk, that leaves a vermiculite substitute.
The big box stores sell pine bark of a fairly fine grind as "soil conditioner." It can vary in fineness brand to brand and maybe even batch to batch. All of it is good for making potting or raised bed soil but only the finer grind can stand in for peat. Usually at least one bag at the store has a little tear where you can see and feel the consistency.