What is this powdery substance ?

Hi guys, need immediate help right now! I'm doing my first batch of Diesel Ryder, and 4 days after transplanting to the netpot (under DWC hydro) ... i get these whitish powdery fungi (?!) on the leca balls ... is this dangerous for my cannabis ? anyone experience this before ? should i remove and replace em balls ?! any suggestions will be helpful!
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That looks like Mold Or Mildew. Never used hydro but that dont look like dry nutes on the balls. Get new ones and get those out man.

WOW! mold... those leca balls are dry, and am wondering how it can happen like that. Do you know what causes this 'mold' ? if i know the reason, i can try to prevent it from happening the next time....

Does it wipe off? Having good FILTERED air intake helps to reduce the amount of mildew spores being pumped into ur area. High humidity with low temps when the lights off can cause it. A dehumidifer or air purifier would help alot. Once again I could be wrong, but that looks like mold.

quick question bro, did you clean the leca balls?

first of all, i'm growing it in a Stealth PC Case , and no chance on having filtered air Light is set on 24/7 as it is autoflowering. Im not sure why it only appears on my 2nd plant... the first plant (15cm away from the 2nd) had no indications of mold or whitish powder.

When i wash them with water the powdery mold gets washed off easily... but im not taking any chances.. i decided to replace em right away ...

I did give them leca balls a good wash with water before using... but apparently, i did not clean well enough...

I'm living in a 29th floor apartment with no plants anywhere near my vicinity .. so i doubt that those mold spores 'flew' to my growbox...

Was wondering, what harm can it do to my cannabis' ? will mold like these, hinder its growth ?!

people say use bleach, hydroton is pourous and will absorb the toxic bleach. I would say the same about ammonia. try to avoid it but i have used it from before and havent had a problem really. i would say either pick up some hydrogen peroxide or in any case, the hands-down best way to sterilize hydroton is with heat. Either bake it in the oven at 350 F for 45 minutes, or pressure cook it at 10 PSI for 45 minutes.

Baking hydroton never comes across my mind though... i have to agree that is an excellent idea. but then again... im only able to remove the top few hydrotons as i dare not touch the bottom ones that is holding the roots in place... this is my first ever grow.. so, i really hope that changing the top hydroton can be the solution temporarily...

lessons learnt.

well at least you will have an idea for next time bro , =)

Mildew spores are in the air everywhere, not just around plants. They can germinate and grow on almost anything they can feed off of

Mold, really? I was going to ask if it might jsut be salt build ups on the hydroton. It has been a while since i used the stuff but I thing I remember white build up like that...

Anyone using hydroton got any input?

I have to agree with the poster above - it does look a lot like salt-buildup on the leca.. I've only seen powder mildew on the leaves, not hydroponic medium(s).

Well, thanks for the input guys... but now, i'm facing another *minor* (?!) but possibly a start to something devastating... the tips of my baby plant (day 12 from germinating) , starting to turn yellow... see pics below... is this something i should ignore or to be taken care of ? I've scoured the net, and found that it may be of 2 possibilites... Lack of Nitrogen and/or over fertilizing... what do you guys think ?!

looks like salt build up as mentioned earlier.. same thing happened here when i was doing hydroponic tomatoes

salt builtup ?! first of all.... i did not use saltwater ,ovbiously.. i use Mineral Drinking Water (hell yeah i did!) by the litres... but i wash em balls on tap... is this because of the nutrients im using ?! well, in this part of the world.. getting off the counter nuts is almost impossible, hence im using a 'normal' hydroponic solution normally used for growing flowering/fruity plants. Which one do you think may be the cause of it !?

@digitalsinz

its not from saltwater. nutrients/minerals have salts. look here on RIU. there should be some resources that break this down for you

digitalsinz said:

Hi guys, need immediate help right now! I'm doing my first batch of Diesel Ryder, and 4 days after transplanting to the netpot (under DWC hydro) ... i get these whitish powdery fungi (?!) on the leca balls ... is this dangerous for my cannabis ? anyone experience this before ? should i remove and replace em balls ?! any suggestions will be helpful!
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I have the same thing happening with my Hydroton. But now I am growing a white "furry" mold on top of some of them. It has even transfered to the stem of one plant. I was reading the post hoping someone would answer your question by giving you a fix for it. This is my first time growing. I thought the white spots were the salts building up until they turned "furry." Maybe I just have two poblemes going on at once, but that looks like my medium just like 2 weeks before it went "furry" in spots. Does anyone know how to kill mold without harming the plant?

TheHighOne said:

I have the same thing happening with my Hydroton. But now I am growing a white "furry" mold on top of some of them. It has even transfered to the stem of one plant. I was reading the post hoping someone would answer your question by giving you a fix for it. This is my first time growing. I thought the white spots were the salts building up until they turned "furry." Maybe I just have two poblemes going on at once, but that looks like my medium just like 2 weeks before it went "furry" in spots. Does anyone know how to kill mold without harming the plant?

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Lysol kills mold and mildew spores in the air. I'd start using it. Salt or mineral deposits tend to look like dried water spots, I'm very suspicious of the spots on that hydroton.

As for the plant, if you had too much N, the leaves would be dark green, your color looks ok. I suspect it is an N defficiency, possibly caused by a PH problem. What is the PH in your reservoir right now? How many ppm are you running on your nutes and what kind of nutes?