All my plants leaves look like this. I’m growing in soil and the ph is 7.0, 7.1. Iv been using miracle grow soluble fertilizer. I’m using a 600 watt hps in a 2x4 tent. The light is 18 inches above the plants. Temps are around 80. Could it be light burn? Any help would be much appreciated. Thanks.
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It could be. That’s a lot of light for a 2 x 4 and that’s very close. PH would be better at 6.5.
Also think there are better nutrients you could use. Just my opinion.
Try raising your light and adjusting PH and see what happens.
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I agree. Looks like your ph could be too high @Justsmkn locking out some nutrients like mg and zinc. But Im no expert with chemical fertilizers…
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It’s boron…
But no, seriously, raise you light and drop you’re starting feed pH to 6.5 and it should take care of itself in a few days…
Soil likes to buffer pH and starting at 7 means its gonna raise a bit as it goes through and sets in your soil… so may be locking things out pretty quick… damage doesn’t look terrible, so should work out well.
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What they said 
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Thanks @Floyd @Upstate @toastyjakes @Jinglepot I will do that
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I’m with @Jinglepot on this 1… also possible overwatering? How wet is your soil ? Is it drying back??
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I water until it runs off then dries out pretty good and repeat
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Can you dim your light? I like 600w per 4x4. 300 to 400w is more than plenty for a 2x4. I have 400w of led that i can only run around 250 to 300w or I get yellowing like that in a 2x4.
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How dry would you say it is? 
like 2 inches of top soil dry?
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IDK about that, my buddies and I used to run 630W son agro HPS lamps in our 32"x32" closets. We could consistently achieve 1oz per plant in 6x6 containers after a one week veg period… that is 84.375 watts per square foot…16 plants per closet. We also ran 1000 watters in 3x3 tents…36 plants per light… with a little over 1 oz per plant yields. That was ~111 watts per square foot. And we never had deficiencies. The plants can take it as long as all other inputs are dialed in. This chlorosis can be from any of the above mentioned divergences from the stated norms. Here is a short read which outlines possible issues which can cause leaf chlorosis:
Why Cannabis Leaves Turn Yellow - Marijuana Grow Shop
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Your too funny.
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Thanks guys. No I can’t dim it. I do believe now it’s most likely a combination of high ph and light burn. I do notice the plants going down last few hours of the on cycle then perk right back up after light comes on.
I want to think that the light will be ok after I flip to 12/12 because they won’t get so much of it…
@Terpsnpurps yes I would say I wait until the top 2 inches of soil is dry before I water. Yeah sounds about right.
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Hey Hun— I’m not the expert-but do have many years of growing under my belt-- and you have multiple issues going on here, some things that Draig and I used to do way back when-and found that it was not the best for our plants…
{I’m growing in soil and the ph is 7.0, 7.1}. :Soil pH should be kept between 6.3 and 6.7 for optimal uptake of nutrients. Always pH the water you use, and the nutrient solution to as close to 6.5 as you can.
{Iv been using miracle grow soluble fertilizer.} Miracle grow is a last resort, as it is not balanced for the needs of your plants, is 100% chemical ,and can be way too harsh for them…use at 1/2 strength!
If you MUST use it, make sure it is their bloom formula! The regular formula has too much nitrogen!
{I’m using a 600 watt hps in a 2x4 tent} That’s a bit much for that size- It can bleach the plants, and dehydrate them…but if it’s what you have - you need to make some adjustments… Keep an eye on the humidity, so it doesn’t get too low- and watch the temps/air circulation (more on that in a minute)
{The light is 18 inches above the plants} It isn’t about the measurement-- it’s about the heat… hut your hand flat at the top of your plants-- if you can feel the heat from the light- it is too close!
{Temps are around 80.} That’s pretty good, if you can get it down closer to 70f you’d be better off… especially with that much light.
You didn’t mention the type of ventilation or fans you are using…You could be drying them out if the fans are blowing right on them instead of circulating the air around them.
Hope this helps you a bit…good luck hun…make some adjustments, and they’ll bounce right back!
[EDIT–NOTE!}
forgot to mention…If you use Miracle Grow because it’s what the store near you carries-- check for bags of something called Espoma Bloom Tone…almost all hardware stores carry it… it is a granular all-organic mix that works well with weed… rub a tablespoon into the top of the soil in your 3-5gallon planters…it takes a couple weeks to kick in-- but you have MG already in there…just use water when the top 3’’ of soil are dry and the planter starts feeling light…and adjust the pH to 6.5 if at all possible!
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Thanks @Lady.Zandra63. I’ll do that. Thanks for the help!
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I have the bulb in a 6 inch cool tube with a 6 inch infinite on the other end. Seems to keep it pretty decent in the tent…
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No Probs hun!
It’s why we all come here-- to help each other!
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With a light meant to cover 2-3x that size tent- you need to keep your temps down around 70-75…and need an oscillating fan or multiple small fans circulating the air in the tent… but not blowing ON the plants!
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I have 2 small hurricane tent pole fans on there way. I’ll make sure of that.
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