10 day seedlings stunted? pics + deets

Hello all.

Here's my seedlings at 10 days, feeling like they're stunted. Still only at first set of leaves which are small and cotyledons still on and green. No new growth for several days now, one has drooping leaves that are pale (near right side). First roots started to show out the base of cube 2 days ago so I assumed they were just putting down roots.

11 were popped, 2 never properly appeared so were tossed. Tangie x Kosher from DNA.

Environment: temps constant 73/74F, humidity between 60-70%, indirect breeze from oscillating fan on other side of room.

Water: around 5ml pH'd tap water (base TDS= 270ppm) 2-4 times daily as the cubes seemed to be drying out pretty quick (likely from breeze and AC). Saturated but no run off.

Feed: no added notes except for a 1/8 strength GH Rapid Start yesterday to stimulate roots (NPK 1-0.5-1 off the top of my head) given yesterday.

Light: 4 bulb fluoro's on 24hrs and approx 10" above canopy. I did have only 2 bulbs running but they stretched pretty quickly so I went with all 4 bulbs after day 5. Just switched to 24/0 last night.

To me these look like 5 day seedlings with a bit of stretch (solved), possible overwatering although should be good in Rockwool. Possibly starving maybe?

What do you guys think???

I'm pretty convinced it is over watering so I just gave each cube a gentle squeeze and extracted something like 8-10ml water per cube. That seems like a lot of water sitting in the cube, right?

I did water 3hrs ago - straight pH'd tap water, 5ml each so that was probably a bunch of it.

I'm glad I ran out this excess, just hope I didn't damage any of those baby root structures.

I've not really worked with Rockwool before so finding the moisture sweet spot, especially at this delicate early stage, seems trickier than expected.

Also, I should be using the trays with square plug holes so I can hide the Rockwool cubes and roots from light penetration. Quick trip to Mr Hydro will sort that.

I, Idiot.

Dropped the cubes in the square hole type trays and added a dome. Hydro shop tossed me a sample of H&G's nitrogen boost and advised a drop or two to be added to my water since roots are starting to show out the cube bottom, which i've done.

Hopefully this is a fix but if you have different ideas i'm happy to hear it. Today seems to be a wig-out day, and we all have those sometimes...

ruwtz said:

Hello all.

Here's my seedlings at 10 days, feeling like they're stunted. Still only at first set of leaves which are small and cotyledons still on and green. No new growth for several days now, one has drooping leaves that are pale (near right side). First roots started to show out the base of cube 2 days ago so I assumed they were just putting down roots.

11 were popped, 2 never properly appeared so were tossed. Tangie x Kosher from DNA.

Environment: temps constant 73/74F, humidity between 60-70%, indirect breeze from oscillating fan on other side of room.

Water: around 5ml pH'd tap water (base TDS= 270ppm) 2-4 times daily as the cubes seemed to be drying out pretty quick (likely from breeze and AC). Saturated but no run off.

Feed: no added notes except for a 1/8 strength GH Rapid Start yesterday to stimulate roots (NPK 1-0.5-1 off the top of my head) given yesterday.

Light: 4 bulb fluoro's on 24hrs and approx 10" above canopy. I did have only 2 bulbs running but they stretched pretty quickly so I went with all 4 bulbs after day 5. Just switched to 24/0 last night.

To me these look like 5 day seedlings with a bit of stretch (solved), possible overwatering although should be good in Rockwool. Possibly starving maybe?

What do you guys think???

View attachment 3744588

View attachment 3744589

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Sure does look overwatered, i agree.
So little time when you've got so much going on huh, it can take a bit of time to dial it all down.

SPLFreak808 said:

Sure does look overwatered, i agree.
So little time when you've got so much going on huh, it can take a bit of time to dial it all down.

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Ha ha, right on. Hydro guy has got me putting the dome on but i've never done this once seedlings have sprouted, especially with humidity already in the 60's without it. Lets see how they do over the next 24hrs. I'm keeping a close eye on humidity & temps in there.

ruwtz said:

Ha ha, right on. Hydro guy has got me putting the dome on but i've never done this once seedlings have sprouted, especially with humidity already in the 60's without it. Lets see how they do over the next 24hrs.

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With a dome, you might want to check on them sooner then 24hrs. More droop = take the dome back off as it will not help an overwatering situation. I start beans at 60rh/80f with no issues if it makes you feel any better. Just keep an eye on them

SPLFreak808 said:

With a dome, you might want to check on them sooner then 24hrs. More droop = take the dome back off as it will not help an overwatering situation. I start beans at 60rh/80f with no issues if it makes you feel any better. Just keep an eye on them

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Yeah as I say I took out much of the excess leaving the cubes moist but not wet. Room = 73F/65%, and in the dome this has climbed slightly over the 1hr or so since adding it, so will be checking on this all day. If the numbers sky then the dome is coming off. I've never domed seedlings at this stage and with ambient RH looking fine I don't know why Mr Hydro recommended it, but here we are.

Way over watered.

Doming works well. make sure the dome has air holes and the medium is nearly dry. Dont add any nutes - way to early (IMO)

OK a couple hours' later in the dome and inside temps have spiked to 86F with RH63% (pretty much the same as room). Dome has come off and i'm knocking the lights down to 2 bulb from 4. These are T5HO fluoros, 54w each so two bulbs is plenty methinks.

The oscillating fan on the other side of the room has been knocked off and there's plenty circulation from the AC vent a couple of feet away.

tldr:subbed

Room temps constant at 72F, under the lights still at 82F, higher than I would like. Temps may have stayed high since killing the oscillating fan.

So I have a toss-up between running 2 bulbs at around 8" off the plants and getting heat, or 4 bulbs hung higher (more power $) and therefore possibly cooler.

I did have 2 bulbs at 12" approx a few days ago but thats when I got stretch (tallest was nearly 2" on first set of leaves). Ergo, light height and intensity is clearly a critical balancing act at this stage.

What would you do?

A bigger intake (which should be down low) and /or a bigger exhaust vent (which should be up high).

You have to get that hot air out.

Osculating fan in room is also good.


Edit..i just converted ur temps to C.(around 25c)..there not to high. Temp is not ur problem

ruwtz said:

Room temps constant at 72F, under the lights still at 82F, higher than I would like. Temps may have stayed high since killing the oscillating fan.

So I have a toss-up between running 2 bulbs at around 8" off the plants and getting heat, or 4 bulbs hung higher (more power $) and therefore possibly cooler.

I did have 2 bulbs at 12" approx a few days ago but thats when I got stretch (tallest was nearly 2" on first set of leaves). Ergo, light height and intensity is clearly a critical balancing act at this stage.

What would you do?

Click to expand...

Foliage temp through radiant transfer is 82f? That sounds pretty good imo but one thing about growing is finding what works for you.
A plant with a foliage temp of 82f will metabolize faster then a plant with a foliage temp of 76f, however the metabolism speed will be limited by the weakest link and you need to stay under that weak link which is only determined by your grow style/genetics and environment.

Seedlings are pretty sensitive,to overwatering and that itself will show major problems if not corrected first

SPLFreak808 said:

Foliage temp through radiant transfer is 82f? That sounds pretty good imo but one thing about growing is finding what works for you.
A plant with a foliage temp of 82f will metabolize faster then a plant with a foliage temp of 76f, however the metabolism speed will be limited by the weakest link and you need to stay under that weak link which is only determined by your grow style/genetics and environment.

Seedlings are pretty sensitive,to overwatering and that itself will show major problems if not corrected first

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Thanks! This is why I asked here! Lets see how they bounce back from the overwatering and I won't sweat the temperature differential for now.

Just make sure u open those vents or burp em...else i smell powder mildew

Lucky Luke said:

A bigger intake (which should be down low) and /or a bigger exhaust vent (which should be up high).

You have to get that hot air out.

Osculating fan in room is also good.


Edit..i just converted ur temps to C.(around 25c)..there not to high. Temp is not ur problem

Click to expand...

Sealed room so I don't exhaust. Really there is no hot air to remove - AC maintains the room and there its slightly warmer at the plant canopy from the T5, but obviously this height can be adjusted to find the sweet spot.

Oscillating fan was running on other side of room and indirect to the plants but I killed it as it was contributing to the cubes drying out too fast and tempting me into the overwatering situation.

Dome has been off since yesterday when temps were up to 86F with no noticeable difference in RH (steady across the room at 65%), ergo dome was doing nothing.

Canopy is 82F / 65-68% today with plants looking a little perkier, so I think we're good. Less watering and moving the cubes into a square hole tray seems to have helped a lot.

Thanks all for your thoughts.

Girls are looking a little perkier today, with cotyledons starting to yellow and fall away, and a couple have really gone for it with their second set of leaves overnight.

Pics may not show too well but there is the slightest pale discoloration on the leaf edges, and some leaves were crinkled although that has reduced a lot since addressing the overwatering. To me they look hungry but I can't be sure.



There looks like there will be one who casualty who looks like she's about to curl over completely, weak/thin stem and dead looking leaves (top middle). Funnily enough she was the first out the blocks and the tallest at one point just a few days ago. I'd like to know which of my poor husbandry skills has killed her.



This is my first turn with seeds in Rockwool and i'm just not convinced that they won't appreciate a light feeding at the 2 week mark, so they've each had 5ml 1/4 strength blend of nutes, rhizo, CaMg and Rapid Start. Several roots continue to reveal themselves out the base on all but the smallest ones, and some advice says this is the point at which seedlings can be fed rather than going by time or size or leaf development; please comment if you have something to add here as i'm very interested to hear from other rockwool seeders.

Also the dome is back on so the cubes don't dry so fast and I can still keep ambient air moving with a fan. Cubes were feeling pretty dry when I came in today. The dome seems to maintain the ambient humidity fine but temps do spike to 85-86F inside.

Otherwise temps at 82F, 65% humidity, T5HO lights at 24/0.

Once we have a few nodes they will be moving into 6" Grodan blocks before flowering in coco, so it really is imperative that I master the watering balance with the rockwool medium.

Any advice appreciated, cheers.

Look really small and unhealthy for two week olds. (pic in my sig of a 15 day old that I had already topped)

I dont use rockwool so im no use to you..lol

Lucky Luke said:

Look really small and unhealthy for two week olds.

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Exactly why I started this thread.