Rockwool mold on clones?

[TheCatsMeow]

hey yall
hope everyone is doing well

for the last two years ive been crushing out some of the best rounds of clones in the wrapped rw cubes- 1&1/2''

recently ive had two rounds completely mold out on me. the cuts themself look great but are still about 4-5 days away from rooting.

has anyone every experienced this? its pretty gross to me and i will now switch from rockwool to something else. big bummer 4 me. i hate having problems arise seemingly out of nowhere

 

[_tessarecting]

You could also use an organic fungicide

 

[lotus710]

put something on top to keep out light

 

[twodogplant]

My biggest gripe with grodan rockwool cubes is that the paper and glue they use to hold the cubes together in the sleeves that they ship them in is VERY conducive to mold growth and the best option I've found is to just throw away the plastic wrapping with the paper on it entirely and get some of those plastic rock wool cube covers or even splurge and get some cube caps:

https://www.hydrofarm.com/p/CCCUBE4

Either way I would throw away all that wrapping (and do so every time you start new plants in rockwool cubes) and get some cube covers, in the meantime spray gently with over the counter 3% h2o2 and that should keep the mold from overtaking everything.

 

[TheCatsMeow]

Well I went a bought a gallon of 3% h202 and submerged the cubes in a bath of the peroxide. I sprayed the leaves with regular h2o to keep them hydrated

Im not sure how long Im gonna keep submerged but no biggie if i lose this tray. They cuts themselves look great so im praying i can get the mold gone before roots pop. last round this happened, i took the paper off after rooting and a friend planted them in his garden. They look great 2 weeks later and have wonderful roots with no sign or problems. i took some more pics of my h2o2 bath

put something on top to keep out light

this has never been a problem before so not understanding why it matters now but if i have to cover the 1&1/2'' cube then ill just stop with them. too much work to keep covered

My biggest gripe with grodan rockwool cubes is that the paper and glue they use to hold the cubes together in the sleeves that they ship them in is VERY conducive to mold growth and the best option I've found is to just throw away the plastic wrapping with the paper on it entirely and get some of those plastic rock wool cube covers or even splurge and get some cube caps:

https://www.hydrofarm.com/p/CCCUBE4

Either way I would throw away all that wrapping (and do so every time you start new plants in rockwool cubes) and get some cube covers, in the meantime spray gently with over the counter 3% h2o2 and that should keep the mold from overtaking everything.

i agree the paper is an issue but i have a friend who has seen this on non-wrapped cubes so its def the rockwool or maybe the glue itself. ive used the 3% h202 as a foliar but it wrecks the leaves eventually after multiple sprays but i appreciate the ideas. im gonna go back to doing root riots i think.

You could also use an organic fungicide

are you speaking from experience or??

 

[corky1968]

Hit them with a 0.5 -1% solution of hydrogen peroxide.

Don't use 3%.

 

[twodogplant]

i agree the paper is an issue but i have a friend who has seen this on non-wrapped cubes so its def the rockwool or maybe the glue itself. ive used the 3% h202 as a foliar but it wrecks the leaves eventually after multiple sprays but i appreciate the ideas. im gonna go back to doing root riots i think.

are you speaking from experience or??

I've been using rockwool cubes for years now but in a generally dry environment, RH is always less than 50% with temps that never go below 73-74 F for the veg. If you use them in more humid places it could lead to some of what you're seeing. I always inoculate my cubes with beneficial bacteria and mycorrhizae when I soak them for the first time and feed them beneficials and mycos on a regular basis to try to keep that stuff from forming, and I usually just get green algae and salt buildup which is solved with a few sprays of 3% h2o2. Whatever tray or container you have them in can contribute to mold as well, which is why I usually just buy new cloning trays every time or very thoroughly clean larger trays with bleach and vinegar.

I used to leave the paper on the cubes and then one time I noticed these little black spots seemingly growing on the paper part of the wrapper that would always get wet during watering and stay wet long enough for stuff to start growing. They looked incredibly suspicious under 100x scope, so I removed all rockwool wrapping from then on and relied on plastic cube covers to keep shit from growing on the top and compromising the plant. See the pictures below for what I'm referring to.

I've made the mistake of using too much h2o2 on delicate plants and nearly killing them, and killing one in a tragic case of stupidity, so if they start to look like they are going tits up just baby them a bit and don't go overboard on the h2o2.

 

[twodogplant]

Also as a follow up, if you're letting your rockwool cubes dry out almost to the point of the plants being parched enough to start losing their turgor pressure (being able to stand upright) then they should never stay wet long enough for this much mold to form. Have you been watering them a lot? How's the air circulation? Do you have a humidity monitor in the area?