Leaves yellowing in the middle?

[deadkndys]

So a few days ago I noticed some yellowing in the middle of a lower fan leaf. Today I noticed some yellowing in the upper fan leaves.
Any idea what the cause is?

Soil Growers:
1. Are you growing from seed or clones?
Seed

2. How old are your plants?
2 months maybe

3. How tall are your plants?
7 inches

4. What size containers are they planted in?
A medium size pot

5. What is your soil mix?
Kellogs patio mix

6. How often do you water and what type of water do you use and how much you give per watering?
Every 3 days until the soil is saturated and also with tap water.

7. What is the pH of your water? 7.0

8. What kind of fertilizer do you use and what is its NPK ratio?
Pure Blend Pro Grow 3 - 1.5 - 4

9. Do you foliar feed or spray your plants with anything? I sometimes drip some of the water/nutrient solution on top of the plants when watering.

10. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights")
150 watt hps

11. How close are your lights to the plants?
About a foot

12. What size is your grow space in square feet? 2 square feet.

13. What is the temperature and humidity in your grow space?
N/A but I would guess 78-86

14. What is the pH of the soil?
7.0

15. Have you noticed any insect activity in your grow space?
spider mites on a clone I bought but took care of them with organocide.

 

[vapor]

"9. Do you foliar feed or spray your plants with anything? I sometimes drip some of the water/nutrient solution on top of the plants when watering."

this can burn plants in light. Your plants look like they want more food how often and at what ppm do you feed?

 

[deadkndys]

ppm is unknown and I feed once per week.

 

[willyweed]

looking at the first photo,looks like too much feed ! they have a big tip burn on them and with the yellowing that would be my guess.try watering with no feed for a watering or 2 !
and the second photo the lips on the edge of the leaf look slightly upturned suggesting too much heat .good luck willy weed

 

[festerous]

Fungus gnat larvae snacking on your roots?