Is anyone able to help identify the type of damage on my seedlings? I have some theories below but would like an eye from an experienced grower
Here is the damage today on one of them, at 26 days old:
Here is the damage when I first noticed it on the same plant, at around 21 days old:
Here is some data about my setup:
I am a first time grower, growing in a DWC hydro setup, following the “Lucas formula”.
Plant Age: My seedlings are 26 days old from the day I put them in a wet paper towel to pop them.
Before the damage was clear to me my reservoirs are 5 gallon buckets and were fed with:
- 3ml/Gal General Hydroponics Micro (Mixed first)
- 6ml/Gal General Hydroponics Bloom (Mixed second)
- A little less than a 1/2 tsp Great White Mycorrhizae (Mixed third)
- General Hydroponics pH Down to adjust to pH target (Mixed fourth)
Before the damage was clear to me here was my environment:
- Light: 200W LED 40%-70% power at least 24” from the top of the plant
- Air temp: 68F-75F
- Humidity: 40%-60% (was usually closer to 40)
- VPD: Around 1.00-1.2
- Water pH: 5.5 - 6.5
- Water Temp: 68F-71F
- Water EC: 600-900
- Water source: tap water
- Chloramine / Chlorine levels negligible according to water quality report
- Under 200 PPM out of the tap
- Water level: .24” below basket, with top feeding ring to help provide root moisture
- Air stones: yes
Theories:
Transplant Shock - the plant that has more damage now was the more robust sprout in my humidity dome out of my two babies. I waited a day or two for the second sprout’s root system to ‘catch up’ before transplanting, at the expense of the first plants root’s poking out of the rockwool being exposed to more light and air. Additionally, the water level in my reservoirs after transplant was beneath the basket. While I did have a top-feeding ring to help keep the root area wet, the plants were not able to immediately find water below. A couple weeks in I did raise the water level up in my reservoirs and roots have grown into the water.
Splash Damage - I initially had a top feeding ring I was using after transplant to help the roots grow in the basket. It was causing a lot of splashing on the leaves as you can see in the earlier picture.
Great White Mycorrhizae Issues - A youtube grower that had what looks like a very similar damage profile claims it was from bunk great white: https://youtu.be/oK10Cm4L6KI?list=PLdjpcVa8bsh2cLKxPl2ULjMxPc0I1qKF0&t=691
Transpiration Issues - I realized that my humidity at around 45% could’ve been quite low for the seedling stage.
Actions Taken:
I have rinsed the roots in tap water, rinsed the reservoir, and re-fed without Great White
I have purchased a humidifier and keep humidity around 75%, VPD around .4-.8
Overall throughout this I see continued root growth and new leaf growth. I try not to compare to other grows too much but they do seem to be stunted from all this, which is what spawned my initial concern. I hope the babies will turn out OK!
