Too much or too little of something (npk)

Hey guys i've got 4 sweet seeds autos under a 250w and in erin multi purpose compost. On the auto blackjack i've got some marks on the leaves I think it's a deficiency rather than nute burn. I haven't fed anything because of the nutrients in the compost and i'm thinking maybe I need to now, so I gave the first feed today which was plant magic organic oldtimer grow which has an npk of 5-3-3. I'm in the UK so I can't imagine any of you in the U.S or anywhere else in the world knowing much about plant magic but it's quite popular here in the UK. Any of you guys give me a second opnion? Also the tips of newer growth are yellow to white in colour. The blackjack is the plant on the back right in the picture of all 4 in the tent. There's nothing wrong with the environment so it must be lacking something nutritional and if it was too much of something it would have happened a long time ago when they were young.

Anybody? Be nice to know if i'm on the right track or not.

I'm thinking either P or mg deficiency or both.

looks fine, if it gets worse, ping us back.

I've found that in plants grown in soil usually show signs of a calcium or magnesium deficiency at about 5 weeks. You can add 1 teaspoon of hydrated lime to 1 gallon of water for a calcium deficiency, which it looks like you could have. I use Calmag personally for the added magnesium it gives. How's your ph?. That can cause similar issues if there are fluctuations in the levels. Remember 6-6.5 is your target. Nice plants by the way. Good luck.

Jimdamick is probably right about the calcium, either from lack of calcium or pH lockout.

Is the oldtimer grow food nitrate based N or urea? If it's nitrate based, it probably has a lot of calcium (check for calcium too), but if it's urea, you'll need to lime the soil.

Thanks guys, is there a way I can check ph of the soil without having to water again to test run off? I can't find any information on the nutes i'm using if it is nitrate or urea. It's getting a little bit worse so if the ph is low then I need to add lime right?

just heat stress is all i see. whatre your temps?

It can't be heat stress, temps are 26c light on and 20 off.

I agree with the cal-mag and/or pH lockout.

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hmm well call me an ignorant american but idk c to f conversion hahaha. but if your temps are solid the i agree with the post above me. or manganese not to be confused with magnesium

Happy Growing

Thanks again guys I can get some garden lime locally if that will give a calcium boost. The ph of water going in is around 7.5 but i'm in compost. Would foliar feeding a bit of garden lime be ok while they're drinking up what I gave them yesterday and then put some in the soil? I appreciate the help guys.

1tsp of epsom salt per gal will take care of her. and for spraying same dilution.

Happy Growing

NWGrower7 said:

1tsp of epsom salt per gal will take care of her. and for spraying same dilution.

Happy Growing

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I thought epsom salts are just for treating magnesium def and would make a cal def worse. I have some epsom salts somewhere so i'll spray them just before the light goes out.

DUUUHH yeah im medicated had that back words.. haaaha

possibly Calcium deficiency

and im not sure about the foliar feed of lime, but if you try it, dilute/mix it well, cus it might burn the leaves

whoa whoa do not spray with lime, from my understanding it will burn it.. but not sure

I'll give it a go at half strength foliar and when they're due another feed which is tomorrow i'll do 1tbsp a gallon and when I mix it i'll put an airstone and pump in the bucket overnight. I found a few threads on fixing cal def and a lot of people have mentioned foliar feeding with garden lime.

Don't foliar feed limestone, it's not really water soluble. It will just get lime powder on the leaves. There's really no point in foliar feeding nutes period.

is your thermometer in your canopy? ambient air can be way cooler than canopy.