Is this a cal/mag deficiency or a overlighting issue?

[KingJames]

I’m running two plants in a DWC and ONLY one of them is showing tiny brown specks. I believe this is the signs of a calcium/magnesium deficiency. The second seedling is slightly smaller but showing no similar signs, which leads me to think that it could be too much light and not a cal-mag def.

Problem is, because the seedlings so young, there’s no roots that have developed so putting cal-mag into the res won’t work. Should I add a tiny amount into the water when I top feed them?

 

[BigCube]

What are you currently feeding it? It's just a baby, right about now is when I would give it it's very first nutrients.

It would be rare for any seedling that small to show deficiencies of any kind, as everything it needs so far was included in the seed.

It is more likely an excess of something, rather than a deficiency.
Like excess top watering or excess nutrients.

For example, I sprout seeds in paper towel and ziplock bags like most people. I plant the seed in a solo cup once the tap root is at least 1/2 inch. When I put the seed in the solo cup, I water it after. I then dont water it again for about a week. Until it looks about like yours does. Then I water it with very light nutrients.

It may be the case that you are watering too much and or feeding too much. It could also be bad PH.

 

[KingJames]

Well, when I placed them in the res, even though there were no external roots, I added nutes (1/4 strength MaxiBloom).

They haven't taken any of the nutes yet (the EC has pretty much stayed the same) but I do top feed the plants with res water. Only one of my two seedlings is showing this brown deficiency though.

I might do a res change and add remove some of the nute strength. It's currently at 1.3 EC (667 ppm) which is an increase since yesterday :S

pH is 5.7.

 

[BigCube]

Try letting them dry out for a few. I assume your in rockwool? Be sure to make sure it's not already soaked before you water.

It may have been too many nutes too soon. But I feel it's more likely too much water, not enough air.

Good luck man

 

[KingJames]

Try letting them dry out for a few. I assume your in rockwool? Be sure to make sure it's not already soaked before you water.

It may have been too many nutes too soon. But I feel it's more likely too much water, not enough air.

Good luck man

Not using rockwool, I'm using root riots.

I've just had to drain and refill the res as the EC was too high (around 1.3). It's now 0.6.

pH is 6.1-6.2.

Plants have been in DWC res for 6 days and there's still no roots showing. I'd initially submerged the net pot about 1 inch, but I've stopped this now and there's an air gap between the pot and the water.

 

[Terpz719]

Not using rockwool, I'm using root riots.

I've just had to drain and refill the res as the EC was too high (around 1.3). It's now 0.6.

pH is 6.1-6.2.

Plants have been in DWC res for 6 days and there's still no roots showing. I'd initially submerged the net pot about 1 inch, but I've stopped this now and there's an air gap between the pot and the water.

FWIW, based on my experience 0.6 is still too strong for those babies. At that stage of growth, I'd go maybe 0.4 @ 5.8-5.9 pH. Good luck with your grow.

 

[KingJames]

 

[BigCube]

Not using rockwool, I'm using root riots.

I've just had to drain and refill the res as the EC was too high (around 1.3). It's now 0.6.

pH is 6.1-6.2.

Plants have been in DWC res for 6 days and there's still no roots showing. I'd initially submerged the net pot about 1 inch, but I've stopped this now and there's an air gap between the pot and the water.

Yeah, definitely sounds like an over watering issue to me. Roots need oxygen as much as they need water, maybe even more. To get roots to grow fast, you need to let the medium dry out between waterings. Not 100% dry but damn close. Roots will show faster growth if they have to search out the water.

I've tried rapid rooter type things before. I wasn't a fan. When I dwc, I use 2" rockwool or growdan in netpots with hydroton. But normally I grow in promix hp or hpcc with peat/coco/perlite/mycorrhizae.

Hopefully someone who has more experience with both DWC and binded mediums will see this and chime in

 

[KingJames]

Yeah, definitely sounds like an over watering issue to me. Roots need oxygen as much as they need water, maybe even more. To get roots to grow fast, you need to let the medium dry out between waterings. Not 100% dry but damn close. Roots will show faster growth if they have to search out the water.

I've tried rapid rooter type things before. I wasn't a fan. When I dwc, I use 2" rockwool or growdan in netpots with hydroton. But normally I grow in promix hp or hpcc with peat/coco/perlite/mycorrhizae.

Hopefully someone who has more experience with both DWC and binded mediums will see this and chime in

This makes sense and basically what I will be doing.

I've lowered the res EC to 0.4, pHd it to around 5.6-5.7 and given an inch or two of air under the pot. Fingers crossed.

 

[KingJames]

Okay so the roots have finally decided to emerge from the pots which is good.

However my res temp is 71.6 and the air temperature is increased to about 76-79 due to a heat surge. I’m going to have to put frozen bottles in there for now until I can paint my second res white and wrap it in bubble wrap and reflectix.

Also one of my seedling looks like this:

While the other one looks like this:

Which suggests to me the left one is experiencing too much light. I measured the lux on the left one and it’s always way more than the one on the right. Not sure why this is because it’s a QB strip

 

[KingJames]

I think I've figured out what the issue was - leaf burn due to oscillating fan blowing on seedlings 24/7.

 

[Aqua Man]

looks possibly fungal. Thats a high humidity area and not sure how much air ya got going in there and comin out of the tiny opening.

 

[KingJames]

looks possibly fungal. Thats a high humidity area and not sure how much air ya got going in there and comin out of the tiny opening.

I mean, I had fans blowing on them 24/7 so the airflow would have been pretty good. Are you sure it's not leaf burn?

It could also easily be nute burn. My EC was way too high initially and although my roots weren't touching the water, I was top-feeding with the nute water, so that would make sense. However, it's only one plant showing the burn and since I was top-feeding both, you would think it was both.

 

[Aqua Man]

I mean, I had fans blowing on them 24/7 so the airflow would have been pretty good. Are you sure it's not leaf burn?

It could also easily be nute burn. My EC was way too high initially and although my roots weren't touching the water, I was top-feeding with the nute water, so that would make sense. However, it's only one plant showing the burn and since I was top-feeding both, you would think it was both.

No I'm not sure but imo looks like a fungal infection. Honestly I would just clip those 2 leaves. Not something I like to do but I would rather be safe than sorry

 

[KingJames]

Damn, okay thanks.