Yellowing lower leaves N def or Mg def???

My 2 autos (Critical Nevilles Haze auto) lower leaves are yellowing. A few leaves have gone a yellow tan colour but the latest leaf is going yellow with green veins.

Nutrient or magnesium def? Which one? Both?

Story so far:
On day 32 from seed
Height: 1 is 45cm the other is nearly 60cm.
Pot- 5 gallon smart pot
Soil: Biobizz light
Nutes: Voodoo juice. Biobizz grow/bloom/topmax, calmag
Feeds: mainly Ph 6.5 water with voodoo juice 2 ml first 2 weeks. Then ph water with 2ml grow in week 3. Noticed slight nute burn then just water for rest of week 3. Started yellowing added grow with next feed in week 4 then added cal mag the other day.

Aside from lower leaves everything else looks good. Leaves do look thin but this is a sativa so thought it was normal. Have not got a soil meter so not sure what ph that is I've just been testing the water for ph 6.5

Am I in trouble? Recommendations please?

Pics:

its a lower leaf, no longer needed, clip it off and carry on.
a deficiency does not mean need to add something, more often than not...
its just the opposite unless you're growing in a dish sponge

chemphlegm said:

its a lower leaf, no longer needed, clip it off and carry on.
a deficiency does not mean need to add something, more often than not...
its just the opposite unless you're growing in a dish sponge

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Thanks for the quick reply, appreciated. Is this normal then for them to go yellow like that? My plant are quite bushy for a auto sativa and the lower one aren't getting any light. I just thought I needed to add grow and cal mag as I read that the plant is taking nitrogen from lower leaves to feed the higher ones hence the added grow feed. Then when I noticed the green veins I added cal mag before it gets any worse. Am I panicking for nothing and started doing more harm than good?

Forgot to mention humidity is 55% and temps are 22c day and 17c at night (can't be helped it's cold where Iam). Oh and I have clipped 4-5 yellowed leaves so far. Scared of doing more.

Viridios said:

. Am I panicking for nothing and started doing more harm than good?

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yes, very few issues are resolved with additions of anything.
overfeeding/watering causes more issues than underfeeding.

chemphlegm said:

yes, very few issues are resolved with additions of anything.
overfeeding/watering causes more issues than underfeeding.

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Thanks I will take heed and feed just water on next couple of feeds. Appreciate it bro.

Viridios said:

Thanks I will take heed and feed just water on next couple of feeds. Appreciate it bro.

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you likely have about 4 gallons of soil in the pot.
fill a pot with four gallons of dry mix and lift it, feel the weight, kick it.
add 1/4th the soil volume in water=1 gallon, all at once.
lift the bag, feel the weight, kick it.

dont water again no matter what until the bag feels like it did when it was dry, right before the plant wilts.

On top of all the good advice above, I would simply say this. If the yellowing on your lower leaves is even in color across the entire leaf, and all the rest of the plant is green and vibrant, don't worry too much and don't change the way you are feeding it. You might let the soil dry a bit more between watering. If the yellowing is between the veins and you see splotches develop, then check your ph and make sure that is correct. If not, fix it. If it is, then you have a deficiency. A little epsom salt might be in order.

DankyDoodle said:

On top of all the good advice above, I would simply say this. If the yellowing on your lower leaves is even in color across the entire leaf, and all the rest of the plant is green and vibrant, don't worry too much and don't change the way you are feeding it. You might let the soil dry a bit more between watering. If the yellowing is between the veins and you see splotches develop, then check your ph and make sure that is correct. If not, fix it. If it is, then you have a deficiency. A little epsom salt might be in order.

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Thanks bro - The leaves start going yellow and the entire leaf spreads the same whilst twisting in the edges with what looks like burn, the veins are the last to go so that's why I added calmag. I think you may be right on the overwatering too as I get worried the top 3 inches are bone dry although there is moisture the rest of the way and I water. Going to leave it to dry throughout them water just ph water then wait to dry and add ferts slowly. Hopefully this will sort it

I'll let everyone know how I go.

Hey fellows just an update it's day 34 took off yellowing leaves-that sort of just came off easily anyway. Can't see anymore yellowing. Hopefully its done the trick. Maaan it's hard just thinking what nutes to put in I know on my next feed I'm just doing water but already thinking about the next feed after: do I add 1ml (half recommended) of grow and bloom (too early for bloom??) or do I go 1/4 strength at 0.5 ml; damn I need a finer tuned pipette! This is the first time I'm growing a plant full stop let alone this lol!!!

I've always found that in general weed is the type of plant that actually thrives on the dry side. I've had scenarios where I'm growing outdoors in 85 - 90 degree direct sun & only had to water once in a 7 day span and the plants loved it. Unlike vegetable plants that needed daily water to avoid death.

How often do you water?

jbcCT said:

I've always found that in general weed is the type of plant that actually thrives on the dry side. I've had scenarios where I'm growing outdoors in 85 - 90 degree direct sun & only had to water once in a 7 day span and the plants loved it. Unlike vegetable plants that needed daily water to avoid death.

How often do you water?

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Hey thanks for the reply. The first 3 weeks was once every 3-5 days. Now I'm on day 42 and it's once every 2-3 days. Was worried I was underwatering and now overwatering. I always wait for the soil to dry out completely and check every day.

Just to chime in, i have a WW auto and all large fan leaves are fully yellow, but close to harvest. Day 73 and harvesting on friday. While your plant is still young ive seen auto being finished at 53 days from seed so that could be a factor as well. Also to one post above, i have 3.9 gal pots and coco and ive only fed once a week and they seem to be growing fine as WW was said to be a light feeder so that is somethi g to concider in feeding lesser or more.

MATTYMATT726 said:

Just to chime in, i have a WW auto and all large fan leaves are fully yellow, but close to harvest. Day 73 and harvesting on friday. While your plant is still young ive seen auto being finished at 53 days from seed so that could be a factor as well. Also to one post above, i have 3.9 gal pots and coco and ive only fed once a week and they seem to be growing fine as WW was said to be a light feeder so that is somethi g to concider in feeding lesser or more.

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Thanks for the post. The yellowing is still happening on lower leaves but not as much. My tent is small so as they are quite bushy I'm assuming this is due to lack of light as everything else on the plants look healthy and due to recent feeds it can't nutrient or mg def. I'm getting more worried about light burn now as they have gone tall and only a few inches from my led 650w. What do you think? Is the white pistils normal?

While i am approaching my first harvest after trying various methods of growing and some complications, ive been rrading since 2012 and yelling leaves getting old at the bottom tend to just get used up and fall off. You might not have any problem at all and they are just naturally leaves the plant is done with. Id say just keep monitoring and let her do her thing. Also believe led need 12" from top of plant or youll get light bleaching and white as hell plants. Higher light and plants will grow taller. Pistels start white and turn dark close to harvest but super albino white means light bleaching.

Your situation sounds like mine that I had awhile back. I did some auto experiments and most all of them acted the same. It was always a couple weeks into flower then the issues would arise. I finally began adding a little calcium and magnesium and the probs went away. The don't take well to be overfed though thats for sure