I've already ordered some to play with, Lee. I don't typically have issues with contamination in my flasks, if nothing shows up in the first few days, but I've been wanting a bactericide/fungicide that doesn't just kill plants outright and is stable for at least a few weeks and at moderately low pH for another little project. These isothiazol(in)ones might just be the ticket. I see they are considered strong skin sensitizers, but I'm not planning to bathe in them and they seem effective in very low concentrations. Thanks to whoever first introduced this topic - I'm sorry I've forgotten who it was - both for the lead on PPM and making me aware of synthetic seeds. I know nothing about them, but it's an interesting idea. Steve On 1/10/2026 7:44 PM, Lee Poulsen via pbs wrote: > That PPM sounds interesting. I’ve tried several other materials and none seem to stop something from growing after a long time. 5 months is great. Thanks for that information. > > --Lee Poulsen > San Gabriel Valley, California, USA - USDA Zone 10a > Latitude 34°N, Altitude 340 ft/100 m > >> On Jan 9, 2026, at 05:30, Tim Eck via pbs<pbs@lists.pacificbulbsociety.net> wrote: >> >> Bob, >> The only nuance you are missing is the fact that the gel medium contains *Plant >> Cell Technologies*' nearly magical concoction "*PPM*" as well as sugar. >> PPM (plant propagation medium?) is a mixture of two chemicals that are >> persistent over time and temperature and prevent *anything *except plants >> from growing. It kills fungi, bacteria, chromista, animalia, etc., which >> means no mold or mildew will develop. >> But you are otherwise correct. No direct connection to an energy source, >> so it will start slowly and need exposure to light, but it doesn't need a >> sterile environment but can be directly planted in a seed tray. I assume >> the PPM will eventually leach out with watering. >> I bought some PPM once to protect chestnut seeds from mold while >> overwintering and I can tell you two things from that experiment - it is >> expensive to make five gallons of solution and those were the only bags >> that had zero mold after five months in the cooler. I also tried hydrogen >> peroxide, bleach, povidone iodine (betadine), benzalkonium chloride, Star >> San, etc. >> It may be worth some members buying some to try on seed or cuttings that >> are prone to mold or mildew. >> Good Luck, >> Tim >> >> >> On Fri, Jan 9, 2026 at 12:43 AM Robert Lauf via pbs < >> pbs@lists.pacificbulbsociety.net> wrote: >> >>> If I understand this correctly, the synthetic seeds might be larger and a >>> bit easier to handle, but "treating them like seeds" is in many ways >>> problematic. Treating them like orchid seeds might be a better analogy, >>> for two reasons:1. Normal seeds have a seed coat to prevent dehydration of >>> the embryo.2. Normal seeds contain endosperm, which the embryo lives on >>> until it makes leaves and starts photosynthesizing. >>> So it would seem that the synthetic seed is roughly analogous to a >>> germinating orchid seed at the protocorm stage, and you couldn't take that >>> and plant it in dirt. It still needs to be in sterile medium containing >>> sugar. If these bodies are somehow encapsulated and removed from the >>> culture medium just for shipping, I would think they would be difficult to >>> sterilize, and if not sterilized, they would immediately contaminate the >>> new medium and you'd have a jar full of mold. Maybe I'm missing something >>> here. If you already have successful propagules of the desired plant in a >>> flask, why not leave them in the flask until they are little plants with >>> leaves and capable of living in the open? >>> Embryo rescue, which I have done, starts with a seed from two parents that >>> are dissimilar enough that the pod parent doesn't recognize it as her >>> offspring and doesn't make any endosperm. But the embryo is in fact alive >>> and viable, but just like an orchid seed (except usually bigger). Imagine >>> a Hipp seed but with practically no "yolk" in it. So you surface sterilize >>> in diluted bleach or hydrogen peroxide, and sow on orchid medium to supply >>> the sugar, and voila. This is probably why it's so easy to make >>> intergeneric orchid hybrids, because orchid seeds have all been germinated >>> by this method anyway. >>> Full disclosure: I'm not a botanist, nor do I play one on TV (apologies >>> to Marcus Welby...) If you don't get that joke, you are probably less than >>> 70 years old. >>> Bob Zone 7 warm with rain on the way; daffs and hyacinths starting to >>> sprout >>> _______________________________________________ >>> pbs mailing list >>> pbs@lists.pacificbulbsociety.net >>> https://lists.pacificbulbsociety.net/cgi-bin/… >>> Unsubscribe:<mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> >>> PBS Forum latest: >>> https://pacificbulbsociety.org/pbsforum/index.php/… >>> >> _______________________________________________ pbs mailing list pbs@lists.pacificbulbsociety.net https://lists.pacificbulbsociety.net/cgi-bin/… Unsubscribe: <mailto:pbs-unsubscribe@lists.pacificbulbsociety.net> PBS Forum https://…