35 sick plants! possible deficiency?

[NEHeads203]

• Hydro or Soil: Soil, Farfax 3B mix
• Type of light? 400W MH 3 feet from plants. also 2x40W T12 floro's on 4 plants, all have problem
• "Atmosphere" Conditions: 70 degrees 68% humidity, 18 inch fan circulating. 4x8x7 grow tent indoor
• Waterings: Watering twice a week with tap water, all are in 1gallon to 1.59 gallon pots
• PH Range: just took test said it was neutral at least 7.0 maybe .1 or .2 higher
• Nutrients/Supplements: Miracle Grow Tomato plant food 18-18-21. watering with nutrients once a week usually go through 2 gallons of nutes when watering 1tbsp/gallon
• Design and Dates 4x8x7 grow tent. they have been in the tent for about a week before that they were in a 3x7 closet and they did not yellow in there. there are 35 plants of unknown strain all 1 month old in the vegetative stage. The discoloration started a few days ago and is now starting to get bad. It looks like a magnesium deficiency to me but I am really just not sure. heres pics of a few of them

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lights seem to be abit to far away(normally around 18") your ph should be no higher than 6.8

[smokeandmirrors]

Originally Posted by NEHeads203

Miracle Grow Tomato plant food 18-18-21. watering with nutrients once a week usually go through 2 gallons of nutes when watering 1tbsp/gallon

simple solution - start using some nutes designed for MJ and not tomatos