Yellow New Growth During Vegetation

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BigBlonde

BigBlonde

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Hello,

We are new to indoor growing and have a problem. The leaves are yellowing badly on one of our plants and slightly on the other plant. Just about everything we've done regarding soil, water, light, etc. as been the same. The biggest difference between the plants is that the yellow plant is several weeks older. We've searched the web and talked with a grower friend and are confused by what we've found so far. We don't know the pH and could use some advice about how to test it. We suspect the most likely problem is the soil and/or the nutrients, but we're not even sure if we have too much or too little.

Our answers to the questions for soil growers are at the bottom of the post.

This the older plant and is the worst.
Yellow leaves on older plant


This plant is several weeks younger. There is slight yellowing.
Yellow leaves on younger plant


Edit:
In a close-up picture, I noticed the points of the leaves have white tips.
Fan leaves close up picture



Questions for Soil Growers:
1. Are you growing from seed or clones?
Seeds.

2. How old are your plants?
About two months. One is a few weeks older than the other.

3. How tall are your plants?
21” and 15” from the soil to the tops of the plants.

4. What size containers are they planted in?
10-gallon fabric grow bags

5. What is your soil mix?
We used MiracleGro potting soil. That may have been a mistake.

6. How often do you water and what type of water do you use?
We water daily and use tap water that has been in an open container for a day.

7. What is the pH of your water?
We don’t know and are trying to find out.

8. What kind of fertilizer do you use and what is its NPK ratio?
We’ve been using a water-soluble 18-18-21 fertilizer that’s marketed for vegetables.

9. Do you foliar feed or spray your plants with anything?
No.

10. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights")
We have a LED light: The Viparspectra XS2000. It has Samsung LM301B Diodes and is 240 Watts of power.

11. How close are your lights to the plants?
31" and 25" from the light to the tops of the plants. The light is at 90% power.

12. What size is your grow space in square feet?
We have a 48" x 48" x 80" Viparspectra enclosure.

13. What is the temperature and humidity in your grow space?
When the lights are on, the temperature is about 78F and the humidity is about 55%.
When the lights are off, the temperature is about 66F and the humidity is about 68%.

14. What is the pH of the soil?
We don’t know and need to learn how to test it.

15. Have you noticed any insect activity in your grow space?
No.

16. How much experience do you have growing?
We’ve grown outside a few times with good results. This is our first attempt at growing inside.
 
Last edited:
mysticepipedon

mysticepipedon

3,629
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The yellowing you see is an immobile nutrient deficiency symptom. This is often caused by pH being too high or too low. Some people use pH indicators for soil pH, others use pH meters or pens.

You are watering way too often and you should find more suitable fertilizers.

Without knowing anything about the pH of your soil and water, the only thing you can do is buy some suitable soil and transplant this plant into it, shaking off as much of the MG soil as possible, without hurting the plant. Then water thoroughly and only water again when the pot feels light, like it did before it was ever watered.
 
BigBlonde

BigBlonde

201
63
The yellowing you see is an immobile nutrient deficiency symptom. This is often caused by pH being too high or too low. Some people use pH indicators for soil pH, others use pH meters or pens.

You are watering way too often and you should find more suitable fertilizers.

Without knowing anything about the pH of your soil and water, the only thing you can do is buy some suitable soil and transplant this plant into it, shaking off as much of the MG soil as possible, without hurting the plant. Then water thoroughly and only water again when the pot feels light, like it did before it was ever watered.
Thanks. This helps us rule out the lights. We'll test pH soon. I suspect it's too high. This is a problem I wasn't expecting to have. We have grown in pots outdoors with about the same soil and had good results. So it's time to read more about immobile nutrient deficiency.
 
GNick55

GNick55

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could be light stress
hard to tell but in first picture the yellowing seems to be starting in all the leafs affected in between the veins? and not starting to yellow closer to the stem of the leaf..
plus the white tips..
light stress is part of it if not the cause of it..
 
BigBlonde

BigBlonde

201
63
could be light stress
hard to tell but in first picture the yellowing seems to be starting in all the leafs affected in between the veins? and not starting to yellow closer to the stem of the leaf..
plus the white tips..
light stress is part of it if not the cause of it..
At first, we thought the plant was getting too much light because some of the leaves were dark green to brown and curling downward, so we reduced the light level and increased watering. That initial problem went away and was replaced by this yellowing problem. Using a light level phone app, I measured 13,000 lux at the top of the plant. I don't know what a good light level would be, though. So maybe we can't rule out a problem with the lights. This is our first time growing with lights, so we expected this would be a learning experience.

Now I'm wondering if the problem was the soil we used or possibly the pH of the water. We ordered a colormetric pH test kit and it should be here in a few days. That will help us know the pH of the water. I need to learn how to test the soil pH.

The distance between nodes is shortest I've ever seen on a plant. I usually think that the distance is determined by the amount of light, with short distances indicating ample light. Now I'm learning that the short distance can also be due to nutrient deficiency. These plants seem to be growing slowly, as well, possibly indicating a nutrient or pH problem.
 
S

Sunasun

78
18
It's definitely light stress. The lower plant is getting a lower dli, hence less yellowing for now. It's so crazy how powerful these lights are. My grand daddy purple couldn't go above 750 dli even in flower without stressing. I've found that indicas tolerate less light strength then sativas. My Maui wowie, I was able to go to 1000 easily. Lower your light intensity and they should start looking way better and even grow faster.
 
S

Sunasun

78
18
At first, we thought the plant was getting too much light because some of the leaves were dark green to brown and curling downward, so we reduced the light level and increased watering. That initial problem went away and was replaced by this yellowing problem. Using a light level phone app, I measured 13,000 lux at the top of the plant. I don't know what a good light level would be, though. So maybe we can't rule out a problem with the lights. This is our first time growing with lights, so we expected this would be a learning experience.

Now I'm wondering if the problem was the soil we used or possibly the pH of the water. We ordered a colormetric pH test kit and it should be here in a few days. That will help us know the pH of the water. I need to learn how to test the soil pH.

The distance between nodes is shortest I've ever seen on a plant. I usually think that the distance is determined by the amount of light, with short distances indicating ample light. Now I'm learning that the short distance can also be due to nutrient deficiency. These plants seem to be growing slowly, as well, possibly indicating a nutrient or pH problem.
So, how much more are you watering? Are you now possibly over watering?
 
freezeland2

freezeland2

2,540
263
It's definitely light stress. The lower plant is getting a lower dli, hence less yellowing for now. It's so crazy how powerful these lights are. My grand daddy purple couldn't go above 750 dli even in flower without stressing. I've found that indicas tolerate less light strength then sativas. My Maui wowie, I was able to go to 1000 easily. Lower your light intensity and they should start looking way better and even grow faster.
750 DLI? You sure about that.
 
Aqua Man

Aqua Man

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Your watering to often which results in poor gas exchange and creates uptake issues. That in turn leads to not enough nutrients to support the photosynthetic demands of the plant and that equals light stress.

Back the light off as far as possible for a few days.

Allow for a longer dry back period. Water to saturate the soil with some run off. Then do NOT water again until the pots are light… they will be noticeably lighter and if you question if they are ready then they are not.

Read this on watering and see how fast they recover from underwatering in the clone video ill link so you can see how easy they recover. Over watering is caused by watering to often not to much



 
S

Sunasun

78
18
Your watering to often which results in poor gas exchange and creates uptake issues. That in turn leads to not enough nutrients to support the photosynthetic demands of the plant and that equals light stress.

Back the light off as far as possible for a few days.

Allow for a longer dry back period. Water to saturate the soil with some run off. Then do NOT water again until the pots are light… they will be noticeably lighter and if you question if they are ready then they are not.

Read this on watering and see how fast they recover from underwatering in the clone video ill link so you can see how easy they recover. Over watering is caused by watering to often not to much



This.
 
BigBlonde

BigBlonde

201
63
I stopped watering yesterday. The plants seem a little greener and perkier. I'll read the watering article and watch the video soon. We also think the plants need to be warmer.
 
BigBlonde

BigBlonde

201
63
Your watering to often which results in poor gas exchange and creates uptake issues. That in turn leads to not enough nutrients to support the photosynthetic demands of the plant and that equals light stress.

Back the light off as far as possible for a few days.

Allow for a longer dry back period. Water to saturate the soil with some run off. Then do NOT water again until the pots are light… they will be noticeably lighter and if you question if they are ready then they are not.

Read this on watering and see how fast they recover from underwatering in the clone video ill link so you can see how easy they recover. Over watering is caused by watering to often not to much
I read your post about watering and watched the video. They were both very helpful. Thanks so much. I can tell you've put a lot of thought into it. You might like this document that I found "CONTAINER SOILS ARE DIFFERENT" that also discusses the perched water table and container gardening. It pretty much says the same as what you wrote. In my other gardening, I have used methods like hugelkultur and bottom watering with success. I have some pots that have gauges that tell how much water is in the reservoir at the bottom of the pot. My Fuscias and Nasturtiums really like those pots and the gauges really help.

I am letting the soil dehydrate and am watching the plants carefully. This is the third day without adding water and they seem to like the change. From what I have learned about immobile nutrients, I understand that I'll need to watch for greener color in the new growth. At this point, the plants have a healthier look to them.

I really appreciate all the help here.
 
BigBlonde

BigBlonde

201
63
The plants started wilting yesterday, which was day five of no watering. We gave both plants about a half gallon of water. They responded quickly, just as Aqua Man said they would. Today the plants look good, but there's still some yellowing. A day after the first watering, they look about the same as they did the last day without water--so no observable change. Now that we have a better understanding of how to water, we can move on to the next learning opportunity.

We finally received our pH test kit. Our water tested at about 7.5 using a colormetric test. A friendly neighbor had the same result. I suspected our water was slightly alkaline. So we'll need to lower the pH. We need something that's best for a few plants growing in soil. At this point, I'm only focusing on adjusting the input water, as it is the next obvious problem. I've been reading about lowering pH, it seems a product like "General Hydroponics PH Down" would be best for my purposes. The product description indicates it can be used to condition water for soil growing.

In other news, we ordered a second 120 Watt light for our 4x4 tent. It should arrive in a few days and we'll before we get to the flowering stage. We're really starting to think ahead to flowering. Before we get there, however, I'm wondering about how to add a second light without stressing the plants and may post about it.
 
Aqua Man

Aqua Man

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The plants started wilting yesterday, which was day five of no watering. We gave both plants about a half gallon of water. They responded quickly, just as Aqua Man said they would. Today the plants look good, but there's still some yellowing. A day after the first watering, they look about the same as they did the last day without water--so no observable change. Now that we have a better understanding of how to water, we can move on to the next learning opportunity.

We finally received our pH test kit. Our water tested at about 7.5 using a colormetric test. A friendly neighbor had the same result. I suspected our water was slightly alkaline. So we'll need to lower the pH. We need something that's best for a few plants growing in soil. At this point, I'm only focusing on adjusting the input water, as it is the next obvious problem. I've been reading about lowering pH, it seems a product like "General Hydroponics PH Down" would be best for my purposes. The product description indicates it can be used to condition water for soil growing.

In other news, we ordered a second 120 Watt light for our 4x4 tent. It should arrive in a few days and we'll before we get to the flowering stage. We're really starting to think ahead to flowering. Before we get there, however, I'm wondering about how to add a second light without stressing the plants and may post about it.
Measure some if the runoff to see what the ph in the soil is. Imo you dont need to ph water. If tou jeed to lower soil ph aomething like aluminum sulfate is a good option but you should test the soil ph before doing so.

If you can link your water report i can better tell you if there is anything in there of concern and if hardness may or may not be an issue. Ph is a result of acid to alkaline nothing more.

 

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