White widow sedlings might be over watered

when i built my DWC setup i also setup a water pump and feeding tubes which ran a slow trickle over the rockwool / hydroton balls 24x7 for the first week or two, i understand now that this is not a good idea so i have switched them to 15 minutes every 4 hours to try and let the roots get some oxygen. My plant are now showing white spots, yellowing on leaves even on new leaves and not growing at all. Have i stuffed these up from the start?

The plants were growing really well for about a week or two then they all started to show signs of deficiency's, i collected some rain water and mixed up a mix of canna at an ec of 1.2 as they are starting to get out of the seedling stage. This hasnt helped at all, they still arent growing and all of the yellowing / spots etc seems to be getting worse, any ideas whats going on guys? im pullin my hair out here

Rockwool gets saturated with water and the water loses oxygen drowning your plants.

Stop watering them until the rockwool is almost dry.

Thanks for the quick reply , i just unplugged the pump now, ill keep you guys updated =]

Dr. Kriz Juan said:

when i built my DWC setup i also setup a water pump and feeding tubes which ran a slow trickle over the rockwool / hydroton balls 24x7 for the first week or two, i understand now that this is not a good idea so i have switched them to 15 minutes every 4 hours to try and let the roots get some oxygen. My plant are now showing white spots, yellowing on leaves even on new leaves and not growing at all. Have i stuffed these up from the start?

The plants were growing really well for about a week or two then they all started to show signs of deficiency's, i collected some rain water and mixed up a mix of canna at an ec of 1.2 as they are starting to get out of the seedling stage. This hasnt helped at all, they still arent growing and all of the yellowing / spots etc seems to be getting worse, any ideas whats going on guys? im pullin my hair out here

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Im thinking that if you are running a DWC then you dont really need to be top feeding them at all.
I usually hand water until I have roots comming out of the bottom of the netcup and then I fill up the bucket with water to about 2-3 inches from the bottom of the netpot, add an airstone and youre good to go. I would follow NLXSK1's advice and stop watering until the rockwool is dry, but then in addition Id Not use that top feed in a dwc. You should however be running an adaquate enough airpump to make the water turbulent with loads of bubbles bursting at the surface.(those bubbles are what encourage the roots dangling in the air above the water to grow down to the water)


Id also get rid of the rockwool cubes Ive never used them but all I have ever heard are people having problems with PH or overwatering, etc etc. I personally like the rapid rooter type plugs, they work for seeds and clones

Rockwood is tricky to work with. I lost some plants when I tried first.

FeFiFoFum is right about rapid rooter plugs. They are easy to germinate seeds in and more forgiving to the newer grower.

Wow, i thought you had to use rockwool, knowledge bombs! im off to my grow store to buy some rapid rooter plugs and get some white widow seeds in them! thanks guys!

Rapid rooter plugs are the way to go !

Hey guys the rockwool has dried out a fair bit now and the seedlings are starting to get a bit of green back into them now , should i bother running the feeding tubes at all? and if so how often, 2 mins every 6 hours or so? While my plants are recovering are there any special nutes i could get that would help them recover faster?

Dr. Kriz Juan said:

Hey guys the rockwool has dried out a fair bit now and the seedlings are starting to get a bit of green back into them now , should i bother running the feeding tubes at all? and if so how often, 2 mins every 6 hours or so? While my plants are recovering are there any special nutes i could get that would help them recover faster?

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One of the biggest problems new growers have is giving too much nutes too fast. Relax.

Are the roots getting moist or are they in the DWC already?

Haha ok yeah their roots are hanging down into the water already on all 4 of them

They should be in good shape then.

yeah no need to ever top feed for the remainder of the grow you can foliar feed if you want.

The plants have some nice dark green growth coming through and the red stems are now clearing up on the bigger one, but the rockwool is pretty much bone dry now and it looks like it has some salt left behind from the nutes after being dried out, does the rockwool need to be damp or is it fine to be dry? i think next time i flush my nutes ill run a bunch of clean water through the rockwool to get rid of the salt buildup

Dr. Kriz Juan said:

The plants have some nice dark green growth coming through and the red stems are now clearing up on the bigger one, but the rockwool is pretty much bone dry now and it looks like it has some salt left behind from the nutes after being dried out, does the rockwool need to be damp or is it fine to be dry? i think next time i flush my nutes ill run a bunch of clean water through the rockwool to get rid of the salt buildup

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The roots are now pulling nutes from the water below. Since they look healthy you do not need to keep the rockwool damp. You will not be able to fully clean the rockwool and some of that salt will remain behind.

My experiments with rockwool were a failure so that is all the info I got for ya.

FeFiFoFUM said:

Im thinking that if you are running a DWC then you dont really need to be top feeding them at all.
I usually hand water until I have roots comming out of the bottom of the netcup and then I fill up the bucket with water to about 2-3 inches from the bottom of the netpot, add an airstone and youre good to go. I would follow NLXSK1's advice and stop watering until the rockwool is dry, but then in addition Id Not use that top feed in a dwc. You should however be running an adaquate enough airpump to make the water turbulent with loads of bubbles bursting at the surface.(those bubbles are what encourage the roots dangling in the air above the water to grow down to the water)


Id also get rid of the rockwool cubes Ive never used them but all I have ever heard are people having problems with PH or overwatering, etc etc. I personally like the rapid rooter type plugs, they work for seeds and clones

Click to expand...

Bless the net! I am considering building some bubbleponic setups using 2 spare 25 gal storage containers. I got a little confused when I seen some other setups using a top feed drip line.

Once the roots are into the nutrient supply, what keeps the plants from over feeding? Do they just draw up what they need and stop?

I use rapid rooter for soil grows and rockwool for hydro grows. You don't have to have either to get a good grow, but I find that it's easier. I also found that 15 minutes on/15 minutes off using a cheap timer works as well or better than running the pump continuously. The bubbler, if used, should be on all the time. Part of the problem might be your choice in plants...white widow is not a great plant to start with and I've had leaf problems with every grow of white widow, but never any problem with Super Skunk, Pineapple Chunk, or Raw Diesel.

Your rockwool should not cause the plant to drown if you're using a bubbler...mine didn't even when I ran the water pump 24/7.

Happy Growing