Miracle Gro Potting Soil and really any of the other commercially available ones are OK as is for some folks. If I used any of them I would definitely amend them with at least a good bit of coarse perlite. You will notice that in all my posts mentioning perlite, I advocate the coarse or even super-coarse perlite. The other grades, which are really fine-medium across the board, are just too fine and don't offer the aeration or even the drainage that coarse/super-coarse afford. You also need to be aware that now most if not all the Miracle Gro soils have fertilizer added, and that fertilizer will be anywhere from a 2 month up to a 6 month formulation.

Rick, if the potting media has the right components, it will be difficult for even someone "addicted" to watering frequently, to over-water. But with the water-sensitive plants, such as cacti, succulents, and terrestrial orchids, watering should be minimized regardless of the potting media. There is really no hard-and-fast rules for watering. Experience is the grand teacher.

drdawg said: You also need to be aware that now most if not all the Miracle Gro soils have fertilizer added, and that fertilizer will be anywhere from a 2 month up to a 6 month formulation.

Which is why I would hesitate to use it (or any potting soil with fert) for starting seed. In fact I would never use any potting soil for starting seeds.

It is even worse. Their Seed starting media is "Enriched with Miracle-Gro plant food".

I use plain-Jane milled sphagnum for most of my seed-starting. Like you, I would never use a potting soil and certainly nothing with fertilizer in it.

drdawg said:Miracle Gro Potting Soil and really any of the other commercially available ones are OK as is for some folks. If I used any of them I would definitely amend them with at least a good bit of coarse perlite. ...

Rick, if the potting media has the right components, it will be difficult for even someone "addicted" to watering frequently, to over-water. ... Experience is the grand teacher.

Some folks manage not to over-water, which is as amazing to me as walking on water would be. If I don't see water come out the bottom, I "know" it needs more water.

But I agree that once you make potting media that drains fast enough, you CAN see water come out the bottom, and it keeps coming out until many of the good-sized voids are filled with air as they must be.

If very coarse Perlite or expanded shale / clay pellets were cheap and easily available, I would probably use them as additives to "professional" mixes with fibers coarser than peat and longer than MY bag of Miracle-Gro was. Crushed stone larger than 1/16th inch would work as drainage enhancers, but be heavy.

Instead I've developed a fetish for screening bark shreds and nuggets. I found a cheaper imitation of ProMix high-porosity, and I add plenty of bark shreds to that so I have a very coarse mix that's much cheaper than ProMix, Sunshine or similar bales.

I could probably stand there with a watering can 24/7, yet STILL not drown the roots.
Until I manage to re-program the 'watering centers' of my brain, that's what I have to do.

I used Douglas fir bark for years (for orchids), but that stuff has gotten really pricey and shipping is high to boot. I have switched somewhat to cypress mulch which is available bagged at Lowe's. It is far cheaper and so far seems to work in my orchid media. I also use the cypress in terrestrial orchid mixes and those are "dirt" based. But I have so many soil amendments that I use routinely for my orchid media (horticultural charcoal, coconut chips, expanded clay, super-coarse perlite, fir bark, long-fibered sphagnum, and cypress) and buy it all in 2-4 cf. bags, I can add any of this stuff to potting soil quite easily. Just today, I made up 15 gal. of medium orchid media (I make fine orchid media as well) since I am in the process of up-potting a lot of my orchids.

My goal for years was to find a source of pine, fir or balsam bark that was half or one quarter the quality of "orchid bark" and at most 1/20th the cost.

Mulch from Home Depot has always been dirty, soggy, fermented logyard trash, for me. FFFPPPTTT.

A local Lowe's has a "pine bark nugget" product that's cheap (?? $4-5 for 2 cubic feet? Very slightly more expensive than HD mulch). The nuggets are clean and dry and I never see pebbles or twigs or dirt. I have to screen it, and will have to grind up the larger bark nuggets some day. For now I use the large nuggets as mulch, and the screenings as soil amendments (including for loosening up my cheap ProMix substitute).

"Cheap" is my first goal. Ken, I think you're more willing than I am to pay what it takes to get sufficient quality for orchids. I'm still trying to find what my seedlings and plants will accept that is as affordable as possible. I don't want to have to re-engineer my mix after I retire and my income nose-dives.

@DavidLMO the grow light I have is a HO with 6 bulbs - it's about 3' long -- I've been very surprised it is so hot under the lights but I've placed a small outdoor thermometer there and checked it -- way too hot.

The HO is a major factor driving the heat.

Good things that I have found as good amendments for hydration and/or aeration purposes. Note that I would not use them all at once and I do not use them all the time. I do use a lot of this stuff when I am potting up my trees and shrubs for sale.

Pine Bark Fines. (Down South sometimes referred to as Soil Conditioner). Not to be confused with mulch. Key ingredient in Tapla's 5-1-1 Mix.

Walmart Special Kitty litter - the original stuff. Calcined clay.

Chicken Grit - granite - not Oyster shells.

NAPA Oil Absorbing product = NAPA # 8822 Floor Dry. Replacement for Turface. Used by many bonsai enthusists. diatomaceous earth.

There is tons of info on the how and why of using these in soil mix, so I won't duplicate the info here.

When I need to kick up the nutrient of course I use composted cow manure (the good stuff if I feel rich at the time - MOO-NURE composted Cow Manure), but also the uncommon items; mushroom compost and cotton burr compost.

I am not cheap, Rick, I am frugal. I really do watch cost. I just have to make a decision whether the expected results are worth the additional price. I know, you are not into growing orchids, and they are my real passion. It was hard for me to begin to use (inexpensive) cypress mulch in place of (expensive) Douglas fir bark. Douglas fir bark has been the industry standard for many decades. Some of the major orchid nurseries have begun to switch as well.

I understand the distinction, Ken, and I agree with you 100% about being frugal. When it's worth it, if you have it, spend it. If there's an OK alternative that saves significant amounts of cash, save it.

I have the vague impression that "real orchid bark" is steam-sterilized. That always made me wonder if there was some kind of bark, and some kind of treatment that would "pop" the bark like popcorn, or expand it like Turface or vermiculite.

Are there applications for which you use sterilized bark?

DavidLMO said:...

Pine Bark Fines. (Down South sometimes referred to as Soil Conditioner). Not to be confused with mulch. Key ingredient in Tapla's 5-1-1 Mix.

Walmart Special Kitty litter - the original stuff. Calcined clay.

Chicken Grit - granite - not Oyster shells.

NAPA Oil Absorbing product = NAPA # 8822 Floor Dry. Replacement for Turface. Used by many bonsai enthusists. diatomaceous earth.

...

Great list! I've never used kitty litter or NAPA # 8822, but I looked up 8822. So THAT is what "kieselguhr" is!
Diatomaceous Earth, Calcined (kieselguhr)
I never knew you could calcine DE. And I had forgotten that DE is crystalline silica (the shells left over when diatoms die).

Do those crumble faster than the bark fines decompose?

All of the Douglas fir bark I purchase is called "sterilized", but in truth, I think it is more like "disinfected". Anyway, it is all heat-treated in some way, perhaps steam is used. The cypress mulch that I have started substituting (for that fir bark) doesn't appear to have any sort of treatment, though it is "clean". As soon as I use the bark, and perhaps as soon as it is bagged, it would no longer be sterile. I just have to settle for clean. I thoroughly rinse it all anyway before mixing it with the other components of my media. The orchids and other tropical plants seem to do well with the cypress so far. Heck, epiphytes surely don't grow on sterile/disinfected surfaces in the wild.

>> All of the Douglas fir bark I purchase is called "sterilized", but in truth, I think it is more like "disinfected".

I agree. If you want "sterile", you need high pressure and temps for over 30 minutes, and even then, you don;t expect to get porous things like wood STERILE-sterile.

I think that even steam-pressure-sterilization only kills like 99.999% of some germs. If you started with 1 million germs, you still have a few left at the end.

>> The cypress mulch that I have started substituting (for that fir bark) doesn't appear to have any sort of treatment, though it is "clean".

>> I just have to settle for clean.

>> Heck, epiphytes surely don't grow on sterile/disinfected surfaces in the wild.

I know nothing about orchids, but that agrees with my own beliefs. Trying to prevent any germs from being present in a garden is not practical or even desirable. We have to create CONDITIONS that favor healthy microbial populations.

Then just be reasonably careful about not shoveling in loads of undesirable microbes: "be clean".

I'm sure that pine bark fines are MUCH cleaner than any mulch I've seen for sale.

I think they shovel that junky mulch up off the forest floor where logging trucks have been running over it and pressing it into the mud. "Logyard trash" stored wet and hence anaerobically fermented in the bag (not aerobically composted, which would have been nice).

But I think/hope that my "pine bark nuggets" product is clean enough for my purposes (crude and basic potting/seed-start mix for unfussy seeds and plants).

I've only skimmed over the replies, so pardon if this is redundant. For most dicotyledon seedlings, you can transplant them deeper to right below their cotyledons (or cotyledon leaf-scar if they've dropped.) However, you do want to give the cotyledons enough space that they don't lie on the soil and potentially rot from excess moisture. If you think about it, the hypocotyl is designed to be both an above-ground and a below-ground structure. The percentage of the hypocotyl that is devoted to one or the other will depend on the circumstances that the particular seedling encounters. My experience has been that the hypocotyl quickly adapts when those circumstances change (such as when I plant them deeper.)

I agree, Rick. Microbes are absolutely necessary for the natural growth of plants. The main thing I want is to have few insects and few insect eggs present in what I use. That and limited fungi spores.

Yup: reduce the numbers as much as practical, but "zero spores" is not an attainable goal. Good point about insect eggs!

We are growing plants in this stuff, not surgically embedding it in immune-suppressed humans.

Right on!

RickCorey said:

Great list! I've never used kitty litter or NAPA # 8822, but I looked up 8822. So THAT is what "kieselguhr" is!
Diatomaceous Earth, Calcined (kieselguhr)
I never knew you could calcine DE. And I had forgotten that DE is crystalline silica (the shells left over when diatoms die).

Do those crumble faster than the bark fines decompose?

I honestly don't know. I do know that I have never been unhappy with any of my mixes using any of the above with the exceptions when I have added too much of something.

I absolutely love the Pine Bark Fines and special order 8 - 10 bags ~ 40 # each from a local nursery where I know tghe owner very well. Otherwise - impossible to find here. I use that in all my mixes for trees and shrubs.

That list was just some of the oddball stuff I use. I also use a lot of Coir now even in my seed starting mix.

I've added more light as suggested (Mr. Ed built some framing to hang it and to give me a way to clip on lights) - so am hoping for stronger seedlings. Time will tell :)

PS @DRdawg you'll probably recognize some plants in that blue bowl on the upper shelf (same GH as the lemons, open the picture to see it) - they're doing well wintering in there where I can monitor them until Mr. Ed gets the next project done - cutting me a nice piece of oak wood to mount them on.