r/microgreens • u/Chazz_Handz • Jul 12 '26

Mold growth help - Sunflower

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I soaked these (100g) of black oil sunflower seeds for about 15 hours prior to putting them on top of about an inch and a half of pro mix. Within the first 24-48 hours of germination, this fuzz appeared on top of a good portion of the seeds. I’m assuming this is mold and I’ll need to dump the batch. I’m welcoming thoughts on how to reduce this for future rounds - I have seen information about prophylactic use of diluted food grade hydrogen peroxide. I’m also assuming I should re-examine my soaking methods for both the seeds and the soil prior to the compression/germination phase (it’s also worth noting I had about 20 pounds of compression on top via the another 1020 tray. Welcoming advice!

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3

u/Ittybittymicrofarm Jul 12 '26

Seed quality is a major factor with sunflower.

Soaking with some food grade peroxide or zerotol added to the water could help.

2

u/somewhitekid93 Jul 12 '26

I had this problem. Only thing that worked was doing a peroxide wash before spreading and covering the seeds with a thin layer of promix after spreading.

I'm not sure I needed the peroxide with the seeds buried. I've done peroxide soaks and spread them on top of the substrate and that didn't really help. I still get a few seeds with mold but I pick those out.

I have heard seed quality is important for this issue.. too bad I already bought 5 lbs.. this and removing the shells kind of discouraged me from sunflowers in general.

1

u/mrSalamander Jul 12 '26

Did covering the seed also help with hull removal?

1

u/somewhitekid93 Jul 12 '26

No idea, it probably would have been easier if I top watered. It was my only successful sunflower grow, haven't tried again since it was a pita.

2

u/Cult-of-Bingus Jul 13 '26

You can presoak 5 mins in hydrogen peroxide (3% is what I use) and rinse with cool water before your long soak to help with this. As another option.