Gold yellow spots on my seedlings, what might it be?

[ChalupaBatman]

Hey guys,

First time grower here. I have two seedlings right now set up in a grow tent, my very first operation and I want to make sure I diagnose any issues as quickly as possible. I've noticed some yellow/gold spots on one of my seedlings that I suspect is related to light burn but want to make sure. Below are the specifications for my grow:

Time so Far: one week in soil
Soil: Nature Care Organic Potting Soil (I know some people are going to be upset with this, but it's what I have, its inexpensive and i wanted to try my best with this)
Nutrients: none, since I've read I should avoid nutes for 3-4 weeks
Water: distilled water, I've been watering every other day, ph level is around 6.
Tent Size: 3 x 3 feet
Grow Light: viparspectra 300w set at a height of 30 inches as the manufacture recommends 26-32 inches (i've moved the light up to 31 in case)
Temperature Range: I have it maintained at a range of 70-85 degrees Fahrenheit
Humidity Range: humidity has been harder to control, it's now ranging from 57 - 70% but 2 times the humidifier was set accidentally too high and for 5/10 minutes hit the 90s. Wondering if this may be the issue.
Ventilation: I have two fans running, one blowing near the plants and another exhausting

I think that should cover it, I have a picture of the soil ph level as well. Any ideas how I should proceed? It's my first grow so I knew I would run into some issues. I've been told this might be a calcium deficiency because I am using distilled water.

 

[AdaminCO]

Hey guys,

First time grower here. I have two seedlings right now set up in a grow tent, my very first operation and I want to make sure I diagnose any issues as quickly as possible. I've noticed some yellow/gold spots on one of my seedlings that I suspect is related to light burn but want to make sure. Below are the specifications for my grow:

Time so Far: one week in soil
Soil: Nature Care Organic Potting Soil (I know some people are going to be upset with this, but it's what I have, its inexpensive and i wanted to try my best with this)
Nutrients: none, since I've read I should avoid nutes for 3-4 weeks
Water: distilled water, I've been watering every other day, ph level is around 6.
Tent Size: 3 x 3 feet
Grow Light: viparspectra 300w set at a height of 30 inches as the manufacture recommends 26-32 inches (i've moved the light up to 31 in case)
Temperature Range: I have it maintained at a range of 70-85 degrees Fahrenheit
Humidity Range: humidity has been harder to control, it's now ranging from 57 - 70% but 2 times the humidifier was set accidentally too high and for 5/10 minutes hit the 90s. Wondering if this may be the issue.
Ventilation: I have two fans running, one blowing near the plants and another exhausting

I think that should cover it, I have a picture of the soil ph level as well. Any ideas how I should proceed? It's my first grow so I knew I would run into some issues. I've been told this might be a calcium deficiency because I am using distilled water.

That’s a liquid pH tester... not for soil.
The soil pH testers have metal prongs, but really don’t work. Slurry tests are really the only way to find out soil pH.
You typically want to be feeding after two weeks. Your input pH should be 6.3 in soil. Start off 1/4 strength and work you way up. Looks like Calcium or Magnesium deficiency. Just need to feed.

I recommend the “How to water” article in my signature.