>> never seen multiple frogs in a flower like that!
Me either! I thought I was hallucinating at first. The only problem is, those frog-zinnia hybrids don't come true from seeds. I should have divided the roots!
>> very good tip about potting up sooner rather than later!
Almost everything I learn about gardening seems really obvious after tjhe plants beat it into my head for a few years. The seedlings seem to stop growing even before the little "plug cells" are root-bound. And a seeedling, outside, that isn't growing fast is overtaken by slugs in a few days.
This year I had some rows of 8 cells put out 5-6 big, helathy seedlings. Then I decided to harden off and tx directly into soil instead of potting up ... during the few days of hardening off the seedlings were muched by slugs and disheartened by something. maybe the 128-cells-per-tray are just too small for Salvia.
>> How do you make your potting mix?
Very very badly until just this year. Starting with commerical peat-based mixes was awful for me - the people who can make that work must have a very light hand with watering. My mix was powdery, always soggy, and let no visible air in. Roots didn't grow down, and stems damped off quickly.
Sand helped only a little. My goal has been to get better drainage and much better aeration. I have not mastered the art of watering LESS, so I need the mix to drain fast and well, especially in the bottom inch or so.
Then Al ("Tapla" in the DG Container Forum) turned me on to chunky or chipped pine bark fines. Apparanetly you can buy double-screened "PBF" if you know where tto look.
I experimented with fine orchid bark - $$$$$ and too large, but great when you screen it to get the small bits. Some day I may use a grater to get vlaue out of the big bits.
I tried pine bark MULCH from Home Depot: cheap but AWFULL. Soggy, fermented, smelly, full of big wood chunks and bark powder. Useless. I tossed the open bag into the compost heap. When I have time to waste opening the other bag, I will screen out the big chunks to use as top-dress wood-chip mulch, and throw everything else into screened clay as rasied bed soil amnedment. Say $2.50 - 43 per 2-cubic-feet and NOT WORTH IT.
Then I hit pay dirt at a pricey but good-quality nursery. $8 for 2 cubic feet. Their "MEDIUM pine bark mulch" had chips, chunks and fibers. Sometimes a bag will be a little wet, but they didn't lie around for months fermenting. No wood chips, huge chunks, dirt, twigs or trash.
I use the "medium" not the "fine" grade. "Fine" has too much that passes through 1/4" hardware cloth. Starting with "medium" I screeen it fast with 1/2" hardware cloth. Anything held back at all is probably too big for a container - certainly too big for seed starting. Then I try to reduce the amounts of too-small stuff by screening aggressively with a 1/4" screen: try to push out anything at all willing to go through. If you get most of the "fines" out, this is VERY airy with LOTS of open space.
This middle grade is very suitable as a base for potting up, and almost fine enough for starting seeds. For starting seeds, I will re-screen with 1/2" mesh to pull out any big bits, and leaves some of the fines in.
Then I add some #2 chicken grit and/or Perlite to open it further. This may not even be needed, but this was my first year with this recipie. The more fines remaining, the more grit you need.
I have a theory that a little coarse sand (finer than grit) would hold bark fibers apart and add even more narrow air channels. As if big bark fibers want to be mixed with coarse grit, but finer bark fibers and fines want some sand. Scaling the grit that holds them apart to the size of the things they are holding apart. Just a theory!
Depending on how much fine bark remains, for SEED STARTING the mix probably needs some very fine stuff like peat, vermiculite or coir fibers. I did that partly because various people told me that "no one uses pine bark for starting seeds", just for potting up. Maybe that's why I had rotten luck germinating petunias for the first time!
This year, I added what was left of a small bag of commerical peat-based mix plus this-and-that leftovers. I regret that because it came out too soggy and I had to add more relatively coarse bark to open it back up.
The ideal sizes of bark (in my opinion) depend on whether you have "fibers", "chips" or "chunks". I would grind big chunks smaller or use them as top-mulch in rqasied beds outdoors. You don't want a big chunk in a small gemrinating cell. And it shouldn't be 50 times bigger than the poor seed trying to puch out from under it!.
A fiber might be up to 1/2 as long as a cell is wide, and add great drainage & aeration. It might be 1/32" to 1/8" diameter. Nice if it is 1/4" long or longer.
"Chips" are probably even better than fibers - small dimension 1-2 mm, largest dimension probably 1/8 to 1/4" or 3/8". Say 1 mm x 3 mm x 8 mm.
I wonder if I took a cheese grater to a pine tree, if I could shave off chips and fibers of controlled sizes? Or if a veneer-cutter applied to bark could produce long fibers of controlled thickness?
Corey
