Moldy Solo Cup Babies - Seeking Guidance

[AbsoluteEgoDance]

I've got a fungus question, hoping somebody can drop by and help me out.
So I've got some mold growing in the bottom of my solo cups. I got overzealous with keeping them moist and the heat mat is there, so you can imagine how that went. It turns powdery & white & has brown spots.
I'd like to nip it in the bud ASAP & I'm planning to use baking soda. Only thing I'm not sure about is application. How would one go about this? It should be watering time soon, so should I water, then have a solution of water and baking soda in a cup on the side to set it in? How much and for how long? Any other household things I could try? H202+RO is only doing so much, but I don't know if it should fizz or anything like that either, so I'm a bit lost.
Worst offender pictured below:

(This is reposted from my current journal.)

 

[OGpapa]

Clear cups in solid cups right?

 

[AbsoluteEgoDance]

Clear cups in solid cups right?

Nope, I've got some hanging around tho' if that's a thing I should do for them

 

[Sueet]

Powdery and white with brown spots on the INside of the container doesn't sound like mold to me. Did you put Myco of any sort in there? If not, I'd guess it is some of your nutrient mix that dripped thru maybe.

If you are 100% sure it is mold, take the plant out of the cup, cut the bottom affected area off completely and put the plant into a different (clean) container, preferably with at least a small amount of soil to replace what you just cut off.

 

[AbsoluteEgoDance]

Powdery and white with brown spots on the INside of the container doesn't sound like mold to me. Did you put Myco of any sort in there? If not, I'd guess it is some of your nutrient mix that dripped thru maybe.

If you are 100% sure it is mold, take the plant out of the cup, cut the bottom affected area off completely and put the plant into a different (clean) container, preferably with at least a small amount of soil to replace what you just cut off.

I'm not using nutes for another couple days & not much has been added to the soil no, it's just FFOF & some extra perlite. I was thinking condensation at first,  then it started looking different.
They'll be asking for water tomorrow morning so I can always do that and give them a little treatment, then wait to see what happens. I do trust your judgement tho'.
For whatever it's worth, they did share a space with plants that had root rot & mold, sanitizing tomorrow now that I have a chance.

 

[bluter]

Nope, I've got some hanging around tho' if that's a thing I should do for them

never use clear cups alone. roots hate light and don't develop well in clear, they will avoid the sides where most of your root bulk would normally grow. clear cups also encourages the nutes in your media to bloom into algae and bacteria which then fights your plant and rots the roots.

 

[Wastei]

never use clear cups alone. roots hate light and don't develop well in clear, they will avoid the sides where most of your root bulk would normally grow. clear cups also encourages the nutes in your media to bloom into algae and bacteria which then fights your plant and rots the roots.

I've personally never had a problem using clear cups for seeds. You've often already transplanted before algae becomes a problem.

Running oxidizers it's a non existent problem. Roots won't avoid the sides of the container in a clear cup, that doesn't happen from my own experience.

 

[bluter]

Roots won't avoid the sides of the container in a clear cup, that doesn't happen from my own experience.

it used to be one of the grade school experiments. half the class grew plants in clear sides and the other in colored cups. colored cups faired better.

 

[AbsoluteEgoDance]

The young ones had a proper H2O2 treatment rather than the baking soda (as per Azimuth's input on my journal) and I gave them some bright red pants.
Things in the bottom of the cup are looking better and I'm seeing root movement again. I'll get some pics when I can get down on the floor

 

[SmokingWings]

I'm not using nutes for another couple days & not much has been added to the soil no, it's just FFOF & some extra perlite. I was thinking condensation at first,  then it started looking different.

When the water percs through the soil it will pick up minerals and soil particles. By the time it gets to the bottom of the container it can have changed color. That could be part of what you are seeing. Depending on which minerals are dissolved in the water could affect whether some of them leave a residue behind that can sometimes start to look like a layer of mold. Hard to tell from that photo.

Not all molds are bad. Most likely by the time it is all said and done most molds are beneficial for the soil and the plant. Try not to panic.

So far we have seen the bottom of the plastic cup. What does the plant look like? That will tell a lot.

 

[AbsoluteEgoDance]

When the water percs through the soil it will pick up minerals and soil particles. By the time it gets to the bottom of the container it can have changed color. That could be part of what you are seeing. Depending on which minerals are dissolved in the water could affect whether some of them leave a residue behind that can sometimes start to look like a layer of mold. Hard to tell from that photo.

Not all molds are bad. Most likely by the time it is all said and done most molds are beneficial for the soil and the plant. Try not to panic.

So far we have seen the bottom of the plastic cup. What does the plant look like? That will tell a lot.

Good to know
At the time of posting this, the plants were looking relatively fine. Right now though they are looking hungry & I'm about to start their first feeding, I will get some "period appropriate" pics and current pics to compare in just a mo'

 

[AbsoluteEgoDance]

One day later..
Here is how the plants looked at the time of posting. The one in the photo is the one with the broad leaves, however they were all having the same residue in the bottom of the cup. They weren't looking too bad and my thought process at the time was, "Yet." A couple were starting to have a little crinkling on the edges of the leaves.

And here is the most recent pic of them all together, + 2 newborns off to the side while the others got their first feeding yesterday.

Close up of the plant in the first photo of this thread, from today. Starting to perk back up after the feeding.

 

[bluter]

looks dry and needs to be fed.

 

[AbsoluteEgoDance]

looks dry and needs to be fed.

Started feeding yesterday

 

[bluter]

Started feeding yesterday

nice. should be on track.

 

[SmokingWings]

Does not appear to be any problem with whatever was showing on the bottoms of the clear cups. Probably would have never noticed it if the cups used were colored instead of clear.

Develop a good watering and/or feeding method. Adapt the method to the conditions as the plants grow larger and as they are transplanted.

Speaking of transplanting. When planning the next transplanting figure on having enough of your chosen soil mix to be able to fill the containers up to very close to the rim. I got in the habit of doing that over the years and now notice the excess empty spacing when I see photos of other grower's plants of any type.

 

[JiggiLotus]

I leave a little spacing from the top so the water doesn't get everywhere when they're getting a drink. And when using the fabric pots, the soil tends to condensed into itself like a ball of soil.? I usually just fluff it here n there with my fingers.