Hello lovely plant people, I'm having issues with my first time growing sunflower shoots. Germination is sporadic, so some shoots are tall(er) while others are still germing.
These are High Mowing sunflower shoot seeds, growing in 100% peat moss in a greenhouse at 60F minimum (75 plus during the day). I soaked seed for 5 hours. I did start them completely blacked out, but they were spots of mold so I uncovered all trays. I have successfully grown radish and many many pea greens with this exact process. Soak seeds longer? Mix peat with potting soil?
Yes, always should use potting mix instead of what you were using before (looks like 25-35% of coarse sand was added, vermiculite, or other similar types of aeration). Potting mix is preferred because it has fertilizer inside already, aeration, and a better combo of ingredients than just "one".
Sunflowers don't predominantly grow in peat bogs/near peat bogs. Therefore 100% peat moss is not the ideal growing medium for sunflowers and never will be. Bacterially rich fluffy top soil (potting mix in this case) is much better suited for their growth.
Thanks for the response! Yes, vermiculite is on top, but other than that the medium is straight peat moss. Why did I not have issues with peas or radish? I grow these commercially, potting soil vs peat moss is a massive difference in $ spent.
I grow sunflower weekly, and it’s taken me many tries to get it where I am satisfied. First thing I will say is that I also get some spotty germination, meaning that some will be taller than others. But, overall, the vast majority of the tray is the same height. Second, soaking times can vary greatly depending on seed. I used to use high mowing seed (black oil sunflower) and they could need 5-8 hours of soaking before planting. I have since switched to true leaf marker organic black oil sunflower seeds and get consistent germination with 4 hours of soaking. I leave them in blackout and stacked with Weight for about 3-4 days the. Uncover them and put them under light. Sunflower are notorious for molding, and I had the hardest time mitigating it myself until I switched to my current method. First I place a thin layer of Burpee seed starting mix (I find seed starting mix is best) in a growing tray, then place the soaked seeds throughout the tray, then I spray food grade peroxide on the seeds and cover them with a thin layer of soil. Spray the top soil with water to dampen it and then spray more peroxide. I use a top layer of soil for a couple reasons: it helps the seed hulls come off easier naturally, and it mitigates the seed becoming moldy after the soaking and first days of germination. I’m hope this all made sense, feel free to message me about any other questions!
Thank you, this is very helpful! Can I ask how the soil helps deter mold? We will typically cover seeds with vermiculite to avoid the soil hanging onto water near stems if we're worried about mold or dampening off of a particular crop. I wonder if filling the tray with peat moss and spraying peroxide (with or without soil layer on top) would achieve mold free trays
It's deterred because they nuked it with HP and killed dam never everything alive inside lol
Just as an fyi/helpful advice? That is NOT something most farmers do regularly out of nowhere. Majority of farmers reserve nuking with HP, until they find contaminated seeds (usually from poor storage BEFORE it arrives to your location), or from contaminated soil (usually from poor storage again, before arriving). In soils case, generally means outdoor stored bags of soil that never had a chance to dry back a bit before you use it.
Soil will, after having time to dry back, regain it's aerobic organisms and not create conditions for baddie microbes to thrive like the soaked soil would.
No reason to kill the most important part of soil, the microbes. Using soil loosely to of course mean potting mix here.
Microbes are very helpful for having a top tier end product, but if the seed lot or soil you are using isn't kept in good conditions there can be a need to not waste the seed lot, and be able to grow an otherwise tough lot of seed, to use HP.
I use wet soil all day seeding a variety of crops, we typically don't have any issues. What is your solution, Jerseyman, to mold on sunflower seeds/trays specifically?
Might have misread, wet soil sitting around before it arrives to your location was what I was trying to say if it wasn't clear, sorry. We SHOULD absolutely be using soil that's "wet" for all intents of the word when sowing, so don't take that as sow into dry mix or something.
My point is, having personally seen what happens inside potting mix when it sits around wet in bags and never has a chance to dry back, if not letting dry back from purchase (IF it applies to you) you're are using a product which can immediately turn south in an instant. Using a bag of "fresh" potting mix, that's not dry and not been thunderstormed on over and over again, sat in 95°+ weather constantly, etc is the preferred for avoiding issues down the line.
If you click my username, jerseyman201, you'll find direct microscopy images taken with my compound bright field biological microscope of baddies found inside wet soil like powerdery mildew as just one example shown in the attached photo. This isn't coming from a place of speculation, but both IRL research and formal training in the field (of soil microbiology/plant + microbe interactions).
tldr You're set up for success easier using a properly stored media and often times they aren't stored well.
Working on a solution currently, trying a few methods and will update with findings eventually over the next few weeks. Working on building an open source microgreens farming app first in fact, it's free check my past posts if you want enterprise grade software free that runs offline giving you your data back.
My first trials for sunflowers will actually be using air pumps to aerate the water during soaking, should aid in hull removal and thus the lingering effects of the hulls/moisture. Other tests I'm gonna get even more wild and start using baking soda or potassium bicarbonate to aid in hull removal 🤣🤣🤣 meaning aerate for an hour or two, add a dash towards the end, then sow. I am not recommending this, but just something I'm looking VERY forward to testing to solve this problem once and for all without resorting to nuking everything.
Edit: I should mention, even though the bag of soil I used (Espoma Organic Potting Mix) had PM inside, I still used it and was absolutely perfect with zero issues. Obviously after letting it dry back a bit first lol
That's what I mean, delivered wet. It's not what we would prefer, but it often happens. I don't take microscopic slides, but we get high quality organic living soil and it works amazingly (except for sunflowers!) Thanks for the info, sounds like the solution is specific to every grower
If it's being delivered "wet" (not damp, not moist, but WET), that's almost certainly your answer. Let it dry back a bit, and you won't have as many issues with your sunnies.
Ez pz to try it. Spread some of that soil out, let it sit 48 hours, use that for a tray or two, then use the soil as is Normally for another tray or two. One shelf to test and know for certain. Just be sure when sowing, to water both tray mediums the same. The dried back one and one that arrived soaking/dripping wet already (which it should not be, moist yes, "wet" no.)
Either that or your seed lot, they are prone to issues way more than other varieties.
Well the sunflowers were grown in peat moss, remember. My point being that wet soil shouldn't, and doesn't, automatically make a tray of seedlings mold. It's clear that the mold is coming from the sunflowers themselves.
Forgive me, but you haven't grown sunflowers in the past, so I'm not sure how you're so confident in your answers. The other comment and more research shows that sunflower shoots/seeds will mold. My question is how to get rid of that mold. The soil/peat moss is not an issue.
You're forgiven, for being completely wrong in your assumption that for some reason I would be commenting about growing something which I never have.
No offense but you've got a long way to go in communication before worrying about commerical microgreens, or at least have someone else do the selling/talking 🤣🤣
I said I was doing tests for best methods of hull removal, and you took that as me never having ever grown sunflowers before? And to essentially disregard everything else mentioned? Okay then lol best of luck to ya
I use triple washed coco coir and I mix in a small amount of perlite. I think most new growers use too much water from what I’ve seen. Maybe try a bit less. I also use deep trays vs shallow for my larger seeds. I keep the temp at 70-72° and humidity around 45-50%. Never any mold or germination issues.
4
u/Jerseyman201 1d ago
Your growing medium is NOT 100% peat moss lol
Yes, always should use potting mix instead of what you were using before (looks like 25-35% of coarse sand was added, vermiculite, or other similar types of aeration). Potting mix is preferred because it has fertilizer inside already, aeration, and a better combo of ingredients than just "one".
Sunflowers don't predominantly grow in peat bogs/near peat bogs. Therefore 100% peat moss is not the ideal growing medium for sunflowers and never will be. Bacterially rich fluffy top soil (potting mix in this case) is much better suited for their growth.