Help: Miracle Gro Potting Mix kills plants

I really hope experts on this forum can help me. I am not all that new to gardening, though I am only recently getting into seed collecting (thanks to a DG'er's prompting) and composting.

I bought a couple of bags of Miracle Gro Potting Mix a few weeks back (my composting bin--well, a long story for another day). The weird thing is: Whatever I plant in that soil--young Coleus, Spider Plant divisions--wilt and die within a week. This has never happened to me before and Coleus and Spider Plants always seemed to be indestructible. I have no idea what to make of it. Any idea?

I once went on a radio question and answer site and told Mike I used Miracle Gro Potting Mix and the answer I received was "Bad Girl"! Wish I had asked why but we weere actually talking more about tomato problems.

It would be hard to say. There are lots of people (myself included) that use Miracle Gro Potting Mix for seed starting and growing plants in containers. I suppose you could have gotten a bad batch.

- Brent

Rhizoctonia, Pythium, Phytophthora, even Thielaviopsis basicola are all rot diseases & distinct possibilities. It could also be one of the wilt pathogens or a mold like Botrytis. I would throw the soil in the trash. Examine your watering methods & frequency too. Saturated soil favors these diseases. Keep soil barely damp only, & do not splash soil onto foliage when watering.

Al

I would throw the soil into the compost and then get some new potting soil.

If you still have the bags, look for a customer service, call and complain. You can at least be heard, and maybe coupons for new bags, although you might not want them.........!

Thank you all for your response! I will get rid of the soil and, if I get a chance, contact Miracle Gro.

Just out of curiosity: Will the composting process kill the wilt pathogens? What about dumping the potting soil over the lawn?

I get confused now and then reading various postings on "good" soil (or "sterile" soil). Until recently, I didn't realize that store-bought soil could kill plants. (Of course I used to feel funny *buying* soil when it's all around me.) I mean I understand different soil has different nutrient properties, but it can't be "clean" or sterile out there in the open. I went to a garden center looking for sterile soil (to grow seeds in) and the lady there looked at me as if I was deranged. And I wasn't sure whether one can indeed sterilize soil. Perhaps I misinterpreted the postings.

So if I dump the soil out (in the woods or in the yard), will mother nature take care of the pathogens? One of the websites suggested by a DG'er says that one can pour boiling water over composted soil to get rid of weed seeds and bacteria. Hmmm.

Blueash, dump the soil in your compost pile!

(I am just putting some peer pressure on you to get that compost pile started...)

Done! :-) Thanks!

Potted soil must not have pathogens, common to soil in the garden. Those pathogens are not a concern because they are part of the decomposition of plant material. It is just when it is confined to the restricted environment of a pot or when plants are emerging these pathogens are bad. Kind of like a cold is nothing to a healthy adult but can be a serious problem to an infant or aged individual.

That makes total sense! Thanks for the explanation.

Joepyeweed: Appreciate your peer pressure :-) Our house came with a compost bin, but it took me a while to figure out what to do with it. But I started adding to the pile before realizing that weeds, weeds with seeds and such should not go into the pile. Then I started adding food scraps (mostly veggies and no dairy or meat). But then mold started to grow inside the bin. Someone told me that the compost was supposed to "cook" (as in heating up, I suppose), but I have not seen any cooking action. During the summer, plenty of flies buzzed around, and the pile did go down in size. So I suppose it was working. But I am all paronoid about spreading mold and fungus (not to mention weeds) into the garden. So I thought of using boiling water (I'd have to boil 40 pots!) or weed suppressing chemicals (but that seems to be against the principle of doing composting). Composting shouldn't be this complicated, should it? So that's the whole story. But I'll keep trying. Thanks!!!

BlueAsh: I don't think mold in the compost is a big deal. I don't worry about it. After all it's a pile of rotting stuff. I just turn the pile, then I can't see it!

Sofer: about potted plants: Is there any benefit to potting soil with mycorrhizae? Can they really do much when confined to a container? Last year I used a compressed bale of regular Pro-Mix for winter sowing, but I see that they do offer one with mycorrhizae and wondered if it really has advantages. Most plants would be planted out in garden beds in spring but some would be for container plants.

Karen

Mold is pretty normal in my compost pile... its part of the process.

I try not to put weeds that are going to seed in my pile... but I do anyway ... because I am a lazy gardener and don't weed as often as I should. I put lots of weeds in my pile. Weeds, especially, garlic mustard, is probably the main component of "green" material in my pile.

If you can get your pile hot, then spreading seeds and plant diseases should not be an issue. However, I rarely get my pile "hot" - because I am also a lazy composter - and don't turn it or moisten it as often I should.

I used to be very particular not letting weed seeds or any seeds in my pile, until a wise much more experienced composter explained to me that "sprouting weeds from use of compost is just another source of greens for the pile". And explaining the circle of compost like that really changed my point of view about weed seeds in compost.

ANd if I use alot of mulch - to control weeds anyway....

I can't see Fungus unless I am in a science lab and have a microscope to determine the structure. So who knows about mycorrhizae? I do know that any of my composts piles are full of fungus and I am happy. Soil structure is made optimal in my garden with wood chips, pine needles, and compost added to my soil when I am building beds. Then I top dress each year another bed that has been there without ammendment and let the worms drag down the soils needed materials. Now with container plants I use just common sense and repot every year or every other year depending on root needs. Each time I add compost and potting soil. And use compost tea to keep the soil cooking to make nutrients available. I rarely have trouble with drainage in my house plants and when I do it is a root trimming that improves the plant. Of course and soil adding to a 1" larger radius Pot.

Generally, people who use compost and teas are already going to be generating fungi in their soils.

I wouldn't "buy" micorrhizae unless I had a specific plant that needed a specific micorrhizae. I have purchased some natives legumes - that were shipped with a special micorrhizae spores. They just came that way , I would not have thought to order it seperately.

I just never have enough compost to go around, and what I do generate I use on flower beds. I never have enough for containers. I don't think I'd go out and buy a bunch of specific fungi. But I will be buying potting soil anyway so I was questioning whether the type with mycorrhizae would have any benefit over one without. I don't think I've seen that particular Pro-Mix in stores. I've only used the regular one (i.e. without fungi added). I'm not even certiain that I could find the one with micorrhizae locally.

Karen

One reason that people make teas is because there is never enough compost to go around. I use alot of unfinished compost in the garden. I save "finished" compost for the containers.

My flower beds are primarily native wildflowers so I don't use any soil amendments or fertilizers on them - saves on compost. :- )

Last fall I "lasagned" 2 existing beds, building around some perennials. The improvement in those 2 old beds was astounding. Yesterday I was out cleaning out those beds for winter and am still so impressed. It's black, soft, crumbly, and crawling with worms. This was a 20+ year old bed with miserable soil.

My tomato beds just got a few inches of mulched leaves for the winter and that did well too. I'm taking that approach this fall, too. Nice composting, only easier. I'm just mulching with shredded leaves. In one bed I mixed in grass clippings (on a rare day when I was able to nag my husband into bagging the grass clippings). I am going to mulch as many beds I can before winter, but I'm running out of time and materials. And I'm a wimp with the cold weather! Trying to convince myself to get out and vacuum leaves now. It's cloudy, cold, damp, and windy (25 mph winds).. My leaves are getting away!

Karen