Terrible fungus on Soil blocks killed most of my plants (hundreds)

So this is my third season using soil blocks, and last year I had a stellar year utilizing them... easily the best starts and best garden I've had, thanks to permies!

This year, luck seems to be against me and I've lost a good share of the seedlings I've started.  Those that did make it have grown very very slowly and are way behind. The previous two seasons I was utilizing a slightly different recipe, but ran across Eliot Coleman's official one from his book and figured it would be more beneficial.

Last year, my recipe looked roughly like this:
* 1 part peat
* 1 part compost (the one with a cow on the front from Home Depot)
* 1 part play sand
* sprinkle of homemade bone meal, which was boiled, cooked/dried and blended down to a powder.

This year, I used something closer to Coleman's recipe for the 2-inch blocks:
* 3 parts peat
* 2 parts compost
* 2 parts play sand
* 1 part garden soil
* Fertilizer mix, comprised of equal parts vermicompost, bone meal (as above), blood meal, fish emulsion, garden lime

All were fresh bags opened right before I mixed them.  I did not sterilize the soil; have never had to before.

The 3/4 blocks I used his recipe with mostly filtered peat and no fertilizer mix.  Of course, no fungus issues on those.

What happened is tri-fold:
* Seeds planted directly in the 2-inch blocks, but covered, failed to germinate.  I had about a 10% germination rate on cauliflower, collards, peppers.  Fresh seeds.  I switched to using the 3/4 uncovered method.  For squash I left these uncovered in the 2 inch, and had great germination, but still fungus I controlled immediately.
* Seeds planted in the 3/4 inch blocks sprouted well and hand no fungus, but seemed to have a hard time rooting properly and have sort of "languished" on the surface.  I had better initial germination rates by not covering them as I did before, but they seem to fail to establish properly and grew very slow.
* Seedlings transplanted into the 2 inch blocks from the 3/4 inch died within 24 hours.  Within 12 hours, I had an incredibly thick white fuzzy fungus, which looks like saprophytic fungus, but resulted in severe and immediate dampening off for alot of the transplants.

The process I followed:
*Mix up the soil and immediately use.  Containers were washed with soap + water in advance.
*For soil blocks, I tried using chamomile tea to wet the soil to make the blocks, hoping to prevent the fungus from starting.  No joy.
*The soil blocks are just wet enough to hold together.
*For seeds, planted and then put on temperature controlled heat mats on the floor (~75 degrees).  Use a small fan for air circulation.
*For seedlings, immediately transplant into the soil and put back under grow lights.  Circulate air with fan.

I've had some success using chamomile, cinnamon and peroxide to combat the fungus, but often its too late.  An example of the blocks attached.

Has anyone run into this problem and identified what needed to be done to prevent this from happening?  Is there something in the fertilizer mix that may have caused this, such as fish emulsion or vermicompost?

Wow, the fungus growth looks intense. It must be frustrating to have such poor germination as well as the struggling plants after putting so much time and effort into planting them. It likely is coming from either the garden soil or the compost, yes? I have wondered if the cow compost from Home Depot (I think Lowe's carries it as well) is safe. It isn't OMRI certified, at least the one I have seen at Lowe's, and I have a strong feeling is comes from factory raised cows who are being given all kinds of antibiotics and other pharmaceuticals to try to keep them alive until slaughter. I'm not sure it's a good idea to add manure from those situations into one's food garden. I am interested to hear what other people on here with more experience have to say about the fungal issue.
One thing I wanted to share, however, is my experience with using microorganisms to ward off fungus/mold. I happen to have used EM1 from TeraGanix, but am currently experimenting with a batch I am cultivating on my own. Anyway, I have been growing microgreens in relatively large amounts for about 4 years now. I grow them to sell so they are going 365 days/ year. One of the types I grow has a tendency to fungus and mold when the air gets warmer which causes the whole affected tray to do poorly and all the plants in it to die. Of course, microgreens are grown unnaturally with very dense seeding so there is always a higher chance of mold/fungus anyway, but here is the amazing thing that I have finally discovered (and am VERY excited about): When I spray the top of the soil and then the seeds after pushing them down onto the soil a bit with the diluted EM1 solution, there is no fungus/mold at all. None. Not only that, but all the microgreens are much happier looking, are growing faster and larger than when I didn't use the EM1. I was so impressed that I also started giving it to my dogs in hopes of having them digest their food more efficiently and that they will thereby need less (the jury is still out on that one). Anyway, I have decided that no matter what I am growing from now on is getting a spray of microorganisms first. I have often heard positive stories to do with probiotics and plants, but to experience it first-hand is always exciting!
I wish you all the best with your next batch of seedlings!

One other thing I wanted to mention is that I, too, tried cinnamon on the soil and a bit on the seeds to try and stave off the fungus/mold issues I had with the microgreens, but never had success. Good thing I really like cinnamon in my desserts and baking because I bought a lot of it being sure it would take care of the fungal issues. lol I have enough to last me the rest of my life and some for my children to inherit as well (and I'm not old). :-)

Wow that is insane growth, to get that fast it must have had a lot of spores already in there, how about you take all the parts of your mix, get a cup of each damp and then keep it in the same conditions as the soil block. see which one goes furry. The put that one in the oven and sterilise it before use.

I'm going to start with complete honesty: I don't know what the best home-made seed starting mix is.

With that disclaimer, I am going to tell you what I use, and I'm going to tell you that it works well enough for me, and is super easy, cheap, and rarely molds -- except when it doesn't have enough airflow.

I use a very simple mix of 50% peat and 50% vermiculite. Into this I plant everything from tomatoes, to cabbage, to lettuce, to beans, to alpine strawberries. I transplant things kind of small sometimes, but most things do really well in this. Basil seems to struggle a bit in my cool basement, and certain other things might grow a little faster but, all things considered, it works really well. I know what you're going to say, "where's the nutrient?" Well, there is a school of thought that says that young seedlings don't actually draw much, if any, nutrient from the soil - until they get bigger. The seeds, themselves, some people say, are super-charged with everything the plant needs for the first stage of its life. I haven't tested this mix against mixes with nutrient, but perhaps I should. But, dollar for dollar, it works pretty darned well.

In addition, I don't have to worry about mold. The only time I have had to deal with mold has been when I have kept everything under a lid for an extended period of time. Even then, the mold is usually nothing to worry about, unless I've introduced some other element to the equation, like cardboard or toilet paper rolls.

I hope this is useful. My feeling is, the more variables you introduce (and compost introduces lots of variables) the more potential there is for stuff like mold, bugs, etc. Spores (and bugs) are literally everywhere. Even if you sterilize the soil, providing nutrient and water is like hanging out a "vacancy" sign. You can always add nutrient later, in the water.

It would be really interesting to test your mix against this simple 50/50 mix. Maybe I'll do that next spring! In the meantime, here are the tomatoes I started in a cool basement in early March (no heat mat). I put them into the garden this weekend. The other plants were started more recently.



Good luck!

Wow, your mix sounds awesome, and those blocks make for quick transplanting. Maybe you make it too rich? I wonder what evil mycelium took over so rapidly. I've heard of people using a lot of sand in their mixes. They say young plants don't need that much.
The fungus must come from an outside source, like Skandi is saying eliminate that one for this year.
But in the future maybe it could be interesting to instead of turf use half decomposed woodchips inoculated by wine caps mushrooms.

Karl, I am quite jealous of your tomatoes!  Mine are way behind and I had to resort to buying plants at the store.

I found that the base mix seemed to work better last year, though I use sand instead of vermiculite.  I had trouble finding vermiculite at the local stores (both garden centers and the lowes/depot/tractor supplies of the world).  Where do you typically find yours?  I am concerned my soil seemed very dense/hard this year even though the sand ratio should be the same?

Skandi, I like your suggestion.  I'll try putting each in separate cups, as well as mixing them in pairs to see which starts the mold.  The cow manure from home depot I used the past few years without issues, so i'm not certain that was it, but I suppose I could have gotten bad batches.  I would prefer to use local compost, but the composting facility near me had tons of garbage (plastics) in it.  Yuk!  I'm working on getting more local sources (horse stables) and have my own cooking, but it wasn't ready yet.

Annie, I will take a look at the EM1 mixture.  I've been trying to keep things basic/organic, and I've been trying to add in and thinking of doing my own organic fertilizers like mushroom compost and vermicompost.  Looks like EM1 is certified organic, so I'll take a closer look.  Thanks!

Hugo, do you grow your own mushrooms?  I tried one year with Shiitake, didn't take, but 3 years later I found one log that appears to have actually taken with it.  I'm looking to try again this winter.

both of the recipes are pretty much the same except one had alot of nitrogen fertilizer (fish and blood meal)

And that is what caused your soil life bloom.

Your original mix had no garden soil mentioned, the second lists it. Microbes are most prevelent in good soils, the first mix didn't have any.

Redhawk

So I made up another batch of the mix, but this time I did so in the outdoor greenhouse.  It's our first season with it, and I was a bit concerned about starting seeds out in it earlier this year, having always done so inside.  (It's a high-tunnel using plastic over metal piping).

This batch did not sprout any fungus.  The outdoor temps have been swinging between 40 degrees at night and mid 60's during the day (we had a cold front; greenhouse is open).  It's been fairly cloudy and humid/rainy.

I'll keep experimenting but the fungal growth definitely appears to prefer the indoors, even with circulating fans and under artificial lighting.

Next I'll try taking some of the batch and bringing it back inside and see if fungus takes off or not.  I might end up switching to outdoor starts, but I'm still wary of seed starting outdoors in the cold month of February.

I have had fungus take over in the past, terrible feeling to lose all your starts.
I use coco coir, fine perlite and worm castings. I will pour boiling water over dry mix then drain out (squeeze out) excess water then make blocks.
( I know heat kills the life in castings, They make the correct consistency though).  I do not use any fertilizer till plants get a few sets of leaves, then I try to up-pot them anyway.
Good luck.

I have had this before,

...and guess twice.
I used green tea as I thought it will benefit and not harm, the mold has the best conditions that it can wish.
All spawns from outside coming in just rain down on your wet soil blocks...
Leave a cup of tea, tea leaves or coffee ground for 3-4 days, I recon that this was the culprit.

And sure I NEVER would use tea and other liquids of any kind again, but only tap water.
Looks like the chlorine in our tap water is here a benefit as well.

But its a good thread, the question is now to all:
- Who uses only tab water for soil block making and never has such a mold growth even without ventilation?
- Who uses tap water and has ventilation but had mold growth in such a dimension as on the pictures?