Cannabis Leaves Turning Yellow What Gives?

[ShadowKhan]

Hey all, my girlfriend and I have recently started growing and so far so good, we've had our ups and downs of course but now we are having another down. Recently, we managed to get our hands on a REAL grow light, and installed it in our grow tent. We had this crappy light we picked up from walmart and finally manged to get it replaced. After we replaced the lights, the plants leafs became droopy and the bottom leafs began turning this yellowish white color. We gave her some more water then we usually do because we suspected underwatering, and a half dose of her first nutrients (apart from what was in the soil of course.) Her leaves perked back up, but the yellowing hasn't gotten any better, thoughts?

 

[BigBlonde]

Those bottom leaves are cotyledons. They emerge from the seed and their purpose is to provide nutrients for the seedling. They normally turn yellow and drop off as new leaves develop.

Your plant does look small and frail, though. It's hard to see, but I don't think it's the light, unless there's too much of it. Seedlings need low light levels.

It may be a soil or nutrient problem. Can you post a still picture that's larger?

I had plants that looked like that. The problem was soil that wasn't absorbing moisture, so the roots couldn't grow. It's best to start them in small pots. I start them in a small four-inch pot. Then I transplant them to a one-gallon pot. Then I transplant them to the final five- or seven-gallon fabric pot. They grow slowly when they're started in a large pot.

 

[ShadowKhan]

Those bottom leaves are cotyledons. They emerge from the seed and their purpose is to provide nutrients for the seedling. They normally turn yellow and drop off as new leaves develop.

Your plant does look small and frail, though. It's hard to see, but I don't think it's the light, unless there's too much of it. Seedlings need low light levels.

It may be a soil or nutrient problem. Can you post a still picture that's larger?

I had plants that looked like that. The problem was soil that wasn't absorbing moisture, so the roots couldn't grow. It's best to start them in small pots. I start them in a small four-inch pot. Then I transplant them to a one-gallon pot. Then I transplant them to the final five- or seven-gallon fabric pot. They grow slowly when they're started in a large pot.

Hey Blonde! Thank you so much for responding. Those bottom leaves are cotyledons? You're sure? I only ask because there was a set of cotyledons on the plant that shriveled up and died weeks ago so I guess I just wasn't aware that a cannabis plant could have multiple sets. Secondly, we are indeed aware of the frailty of the plant, as around the beginning of last month she got really sick along with two other plants that ended up dying. We did an emergency transplant into the pot you see her in now. As for nutrients, as I had stated before we recently gave her, her first dose of nutrients we have ever given her. We only gave the plant about a half dose and she perked up a little bit.

 

[GNick55]

the yellowing won’t go away if anything it’ll slowly get worse..
what’s that black tube in the soil?
and what’s a half dose? how much of what?

 

[ShadowKhan]

the yellowing won’t go away if anything it’ll slowly get worse..
what’s that black tube in the soil?
and what’s a half dose? how much of what?

If it's the black tube I think you are referring to, it's a temperature reader from the heating mat sitting under the pot, so we could keep track of soil temperature. We gave her .3 mL of general hydroponics nutrients.

 

[GNick55]

If it's the black tube I think you are referring to, it's a temperature reader from the heating mat sitting under the pot, so we could keep track of soil temperature. We gave her .3 mL of general hydroponics nutrients.

ok no need for heating mat now..
take a picture of the plant looking down at her..

 

[BigBlonde]

Those bottom leaves are cotyledons? You're sure?

Yes, from what I could see. Cannabis is in the group of plants known as dicotyledons. The name refers to one of the typical characteristics of the group: namely, that the seed has two embryonic leaves or cotyledons.

As @GNick55 said, we need better pictures.

 

[N1ghtL1ght]

Yes, from what I could see. Cannabis is in the group of plants known as dicotyledons. The name refers to one of the typical characteristics of the group: namely, that the seed has two embryonic leaves or cotyledons.

As @GNick55 said, we need better pictures.

No, the yellow leaves are the first set of true leaves which for a Cannabis seedling has only 1 leaflet. The node below there would be the cotyledons but they are already gone. You're plant shows typical signs of a nitrogen deficiency, which is characterized by yellowing from the bottom up and easy leaf-fall after that.

What kind of a soil is this, it's very unusual happening that early in such a big pot.

 

[BigBlonde]

No, the yellow leaves are the first set of true leaves which for a Cannabis seedling has only 1 leaflet. The node below there would be the cotyledons but they are already gone.

Okay, you're correct. I couldn't see the leaves very well. I looked again and can see it now. Sorry about the mistake. My 71-year-old eyes don't see well sometimes.

You're plant shows typical signs of a nitrogen deficiency, which is characterized by yellowing from the bottom up and easy leaf-fall after that.

Yes. I've seen that nitrogen deficiency problem with some of my plants, too. Nitrogen is a mobile macronutrient.

 

[Deadstill]

Yeah, as Gnick said, the yellowing won't go away.

Once a leaf is damaged it generally stays damaged, I've never seen a leaf repair itself in all my years of growing. What you want to avoid is having it happen again to the newer leaves.

I, too, am curious what kind of soil you are using? And is this an autoflower strain? Otherwise I generally avoid using such large pots for seedlings. It makes watering a little more difficult in a large pot.
But yeah as Nightlight said, it looks like it needs some nitrogen. Are you using a coco or soilless medium? If so, may need to up your nutrients just slightly. Also keep in mind, if you are in fact in coco, you'll want to use a little more cal-mag than you would use in soil.

Idk. I just woke up but those are my initial thoughts.

Keep up the hard work and keep us posted, there's a lot of very knowledgeable growers here, and we're happy to help!

 

[ShadowKhan]

Yeah, as Gnick said, the yellowing won't go away.

Once a leaf is damaged it generally stays damaged, I've never seen a leaf repair itself in all my years of growing. What you want to avoid is having it happen again to the newer leaves.

I, too, am curious what kind of soil you are using? And is this an autoflower strain? Otherwise I generally avoid using such large pots for seedlings. It makes watering a little more difficult in a large pot.
But yeah as Nightlight said, it looks like it needs some nitrogen. Are you using a coco or soilless medium? If so, may need to up your nutrients just slightly. Also keep in mind, if you are in fact in coco, you'll want to use a little more cal-mag than you would use in soil.

Idk. I just woke up but those are my initial thoughts.

Keep up the hard work and keep us posted, there's a lot of very knowledgeable growers here, and we're happy to help!

We are unaware of what kind of strain this is, as this is our first grow and we just picked up bag seed from our local dispo . We are using Root Organics 707 as our medium. We transplanted her in the pot she is in now on 4/5/23 so we knew that the nutrients would run out eventually, I guess we just waited a little too long... whoops.

 

[ShadowKhan]

No, the yellow leaves are the first set of true leaves which for a Cannabis seedling has only 1 leaflet. The node below there would be the cotyledons but they are already gone. You're plant shows typical signs of a nitrogen deficiency, which is characterized by yellowing from the bottom up and easy leaf-fall after that.

What kind of a soil is this, it's very unusual happening that early in such a big pot.

Hey N1ght, the soil we are using is Root Organics 707. She's been in that pot for a little over a month now, so maybe the nutrients in the soil is running out?

 

[ShadowKhan]

ok no need for heating mat now..
take a picture of the plant looking down at her..

Here you go :), sorry the picture is so crappy, I tried my best but my camera sucks.

 

[BigBlonde]

My current grow of Amnesia Haze just didn't want to grow. The plants looked like miniatures. After a month, the leaves barely spanned the width of a quarter, and the stem was smaller than a pencil lead. I eventually decided any attempt to get them to grow was worth the risk of losing them. So, I took them out of their 4-inch pots and found that the soil underneath the plants was dry, even though I had watered them carefully. The problem was the soil! I knocked most of the soil off the roots and put the plants in the soil mix I had prepared for the next level of pot size. To give them a boost, I mixed nutrients in a gallon jug of water and poured small amounts of that solution (about 40 ml) near the stem (which is often not recommended because can retard root growth) till the plants started growing normally. I added the nutrient solution because the plants were so small and weak. The plants quickly recovered and are now in one-gallon pots and ready for transplanting to their final homes.

Here you go :), sorry the picture is so crappy, I tried my best but my camera sucks.

I saw this after I typed my story. Thanks for the pics. They help a lot.

 

[alpha.ganjaguy]

What light are you running, what is the wattage? How far from your plant is it?

 

[ShadowKhan]

What light are you running, what is the wattage? How far from your plant is it?

I'm running the Phantom Pheno 440, and it's about 3 feet away from the plant.

 

[alpha.ganjaguy]

I'm running the Phantom Pheno 440, and it's about 3 feet away from the plant.

440w at three feet should be fine, most likely upping the wattage made her start photosynthesizing more which now is displaying itself on the lower leaves as it wants some food now. You may want to start her off at 50% the suggested feed rate for your nutes.

Also what are your temps and rh like?

 

[ShadowKhan]

440w at three feet should be fine, most likely upping the wattage made her start photosynthesizing more which now is displaying itself on the lower leaves as it wants some food now. You may want to start her off at 50% the suggested feed rate for your nutes.

Also what are your temps and rh like?

Ever since we've added the pheno 440 (we just got it a couple of days ago) the temp has been ranging from 75-78 degrees. Before, with the old light we had it had been ranging from 68-73 degrees. We keep a relative humidity level of around 60-65%

 

[alpha.ganjaguy]

Ever since we've added the pheno 440 (we just got it a couple of days ago) the temp has been ranging from 75-78 degrees. Before, with the old light we had it had been ranging from 68-73 degrees. We keep a relative humidity level of around 60-65%

those numbers are good, so the environment has just changed to a more hospitibal place for the plant, I would expect it to really start to take off now..

I stick with my opinion of starting her on a 50% feed strength and seeing how she responds. Yellowed leaves will not change back to green but keep an eye on the new growth to show you how she's taking to the feed.

 

[Poekie]

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Here you go :), sorry the picture is so crappy, I tried my best but my camera sucks.

You just need to focus the camera on the plant.
Now the soil is sharp and the plant is not.