Day 8 Since Germination...Seeing Trouble with Young Seedlings

[Millwill]

Hello everyone! I am a first time grower. I planted seeds 8 days ago and my progress pictures are attached to this post.

I am seeing a few potential problems and a requesting some advice from experienced growers before I try and solve these issues.

1.) Middle area of first set of real leaves are yellow
2.) Tips of first set of real leaves are brown and strange growth on cotyledon leaves
3.) First set of leaves are curling up​

What do you think are the causes for the issues I am seeing and what type of solutions do you recommend? Any and all advice is welcomed!

Background Info:

(10) seeds were germinated using the paper towel method. I soaked the Rockwool cubes over night in pH adjusted water (5.0 to 5.5) before planting the seedlings. I have (softened) well water, so I pH'd it down from 7.0-7.5 to 5.0 to 5.5. I measured 183 PPM of the water.
Once the seeds started to germinate, I moved them to Rockwool cubes (one seed per cube). I am not using nutrients at this point.
The Rockwool cubes are sitting underneath a T5 grow light with (4) lamps (all of which are being used; I can turn off half). I was misting the dome and seedlings daily with pH down adjusted water (5.5 - 6.0) once the seedlings were planted in the Rockwool cubes, but recently stopped altogether. I also removed the clear plastic cover of the humidity dome.
The tallest seedling (2" tall) is 14" away from the light.
I have a timer which turns off the T5 light for 4 hours per day. During the other 20 hours, all (4) lamps are on.

Today when the lights were on, the humidity of the area where the seedlings are was at 35% and the temperature was 82 degrees Fahrenheit.
Later today, when the lights were off, the humidity increased to 43% and the temperature decreased to 74 degrees Fahrenheit.
I have (2) fans running, one which oscillates back and forth (but isn't quite tall enough to directly reach the seedlings; the seedlings are not having air blown directly at them) and one which is pointed up and out from the area where the light and seedlings are at.
I have also removed the toothpicks from the Rockwool cubes which can be seen in the pictures (they were markers for the strains).
Once I overcome these issues, this will be a hydro grow with drip lines.

If you need further background information, just let me know and I will reply ASAP.

Thank you in advance!

Pictures:

Yellow Area Middle of Leaves:


Brown Tips/Strange Growth:


Leaves Curling Up:

 

[*BUDS]

Its a hard one this, i think the seeds are poor quality or could be over watering. When you water the cubes only wet them 50% not saturate them. The seedlings like the medium to dry a little between watering's after germination. Use scales to roughly judge how to wet them 50% then go by feel. No more misting etc.

 

[Bugeye]

Is your water softener salt based? If so, stop using it for plants.

Never dome seedlings or mist them, this only leads to damping off (not your problem here).

I think you need to add some cal/mag. Seedlings don't need much nutes, but a little cal/mag in your water is important.

Try to get your temps down below 80F.

 

[Millwill]

Is your water softener salt based? If so, stop using it for plants.

Never dome seedlings or mist them, this only leads to damping off (not your problem here).

I think you need to add some cal/mag. Seedlings don't need much nutes, but a little cal/mag in your water is important.

Try to get your temps down below 80F.

Thank you for your reply. My water softener is salt based. If I am never to dome or mist the seedlings, would I need to add water directly to the Rockwool cube? Would it be OK if I used distilled water for the seedlings? If so, do you have an amount in mind for how much Ca/Mg would be needed?

 

[Millwill]

Its a hard one this, i think the seeds are poor quality or could be over watering. When you water the cubes only wet them 50% not saturate them. The seedlings like the medium to dry a little between watering's after germination. Use scales to roughly judge how to wet them 50% then go by feel. No more misting etc.

Thank you the reply. The Rockwool cubes were more than 50% saturated when I planted the seedlings, which may part of the reason why they are possibly overwatered.

 

[Millwill]

Should I flush the Rockwool cubes soaked in the softened water with distilled water to try and remove excess salt? My worry is that apart from using softened water, that I overwatered it to begin with and flushing out the cubes will saturate them even more. To flush, or not to flush?

 

[Bugeye]

Should I flush the Rockwool cubes soaked in the softened water with distilled water to try and remove excess salt? My worry is that apart from using softened water, that I overwatered it to begin with and flushing out the cubes will saturate them even more. To flush, or not to flush?

Just switch to something else at next watering. If it is distilled or RO water, something with little or no ppm, you need to add cal/mag to it. Just follow the directions on whatever product you use, typically 1 tsp per gallon. Good luck!

 

[Millwill]

Just switch to something else at next watering. If it is distilled or RO water, something with little or no ppm, you need to add cal/mag to it. Just follow the directions on whatever product you use, typically 1 tsp per gallon. Good luck!

Thank you for the advice! I didn't read this reply until now, so it has been about a week and I have been using just distilled water (pH adjusted down to around 6.0). The new growth looks green and healthy. I am going to order some cal/mag tonight per your recommendation.

The picture below is of the seedling that had yellow/brown tipped leaves:


The seedling below had the growth on its first set of leaves: