[rainAgI4]

Hi all got some mandala babys bout 2 weeks old

The other day I started feeding them a little bit of Canna's Rhizotonic, and I added a Odor Killer Gel container to the room.

Yesterday I noticed some yellow spots forming on 2 of the babys, I tried rubbing them off but they wouldn't really go away.

It's just some yellow spots, I don't know how else to describe it, but today it has spread and gotten bigger.

For now I have removed the Odor Killer Gel and am discontinue feeding any nutes to see if it clears up.

Any idea what it is mike?

And, when a plant starts yellowing its bottom leaves and gradually yellows the other leaves 1 by 1 what is this caused by?

[rainAgI4]

I have come to the conclusion the yellow spots were caused by water droplets forming on the leaves and then the HPS light burns the leaf and causes the yellow spot.

The reason I believe this is I put water on my fingers and tried rubbing the yellow spots off one of the plants, it didn't come off. But the next day the entire leaf was yellow and curled, and it is now dry and basically a dead leaf.

When water droplets get on the leaves they act like magnifying glasses and make the HPS light burn the leaf.

Could anyone confirm this theory for me? I'd really like to figure out what the hell is causing this :-(

As for the leaves yellowing on the bottom and gradually moving up the plant, I believe this is a nitrogen deficiency after reading about that, is this true? The first set of leaves turn completely yellow, dry up, and fall off. And each leaf does this 1 by 1 going up the plant.

[rainAgI4]

Mike, I emailed Canna, my nutrient company, and they responded with this:

Off hand I would say they could be one of 2 things depending on if they are just on the leaf surface or on both upper and lower leaf surfaces. Probably you are seeing endema, a condition caused by water relations problems. If they are coming out of a period of poor water uptake due to any reason such as many cloudy days then full sun, being kept a little dry then holding wet for a period, or, on cuttings, an extended period of root formation and associated lack of water uptake then sudden and quick availability of water from a full on root system (the likely culprit). It is not pathogen based but rather caused by 'blisters' in the leaf cuticle which form in damaged tissue and burst causeing a yellow moving to tan/brown small spots. It should not spread and will not go away as the tissue is dead. After plant establishment, the affected leaves will likely finish yellowing up and fall off.

[MandalaMike]

Originally Posted by rainAgI4

I have come to the conclusion the yellow spots were caused by water droplets forming on the leaves and then the HPS light burns the leaf and causes the yellow spot.

The reason I believe this is I put water on my fingers and tried rubbing the yellow spots off one of the plants, it didn't come off. But the next day the entire leaf was yellow and curled, and it is now dry and basically a dead leaf.

When water droplets get on the leaves they act like magnifying glasses and make the HPS light burn the leaf.

Could anyone confirm this theory for me? I'd really like to figure out what the hell is causing this :-(

As for the leaves yellowing on the bottom and gradually moving up the plant, I believe this is a nitrogen deficiency after reading about that, is this true? The first set of leaves turn completely yellow, dry up, and fall off. And each leaf does this 1 by 1 going up the plant.

Ok, first of all don't panic and take a deep breath.
Water drops are not going to burn the plant unless your lamp is much too close. In which case they are already burning from the heat anyway.

The yellowing can be from a nitrogen deficiency. BUT a 2 week old plant doesn't just get an N deficiency unless there is a serious problem in plant care: pH imbalance, small pots, crappy soil are the most common culprits.

The yellow spots can be caused by the Rhizotonic in which case symptoms should stop when you discontinue it. I also advise against using root boosters.

The following can help determine what, if any, action needs to be taken:

1. Check the pH of the water - it should be 6.2-6.5. Make sure your meter is calibrated if you are using one!
2. Provide the following info:
what soil mix do you have, how big are the pots, what is the distance to the lamps?
3. Are you watering a lot, have you ever flushed the pots, is the soil soggy-wet at any time? Or have the pots dried out often?
4. Have you used any pesticides?

[rainAgI4]

1. Check the pH of the water - it should be 6.2-6.5. Make sure your meter is calibrated if you are using one!

- I just bought a ph meter so I will check with my next waterings, I am a soil grower though, so I can't measure my soil, just the water I feed with.

2. Provide the following info:
what soil mix do you have, how big are the pots, what is the distance to the lamps?

- Fox Farm Ocean Forest Soil, No additives like perlite, just out of the bag.
- They were in solo cups for 2 weeks, now in 2 gallons.
- 150 Watt HPS, Was about 1 foot away, now 1.5 to 2 feet away.

3. Are you watering a lot, have you ever flushed the pots, is the soil soggy-wet at any time? Or have the pots dried out often?

- Water when the top layer gets dry, Never flushed, Never soggy, I would always let the top layer dry out before watering, not sure about underneath.

4. Have you used any pesticides?

- No

[MandalaMike]

Originally Posted by rainAgI4

I just bought a ph meter so I will check with my next waterings, I am a soil grower though, so I can't measure my soil, just the water I feed with.

Thanks for the info.
This explains the yellowing. You don't need to check the soil pH if you are using quality potting soil like Fox Farm.
BUT you must always water the correct pH. Otherwise nutrients become unavailable (locked) for the plant.
The plants should recover within the next week once you water with the correct pH.

A lamp distance of 1- 1.5ft with a 150W HPS is possible. It is only going to stress them if they get light but not enough nutrients. Once they are all green and perked up you can lower the lamp again.

Cheers,
Mike

[rainAgI4]

Im sorry i dont understand, What causes the yellowing??? Your saying the water's pH did it?

Could you explain this:
It is only going to stress them if they get light but not enough nutrients.

So your saying they have enough light but not enough nutrients? And the reason they dont have enough nutrients is the ph?

The yellowing seemed to stop, I find it hard to believe it was from deficiency or even incorrect PH because only 2 or 3 of them did it and I have 17 mandalas total.

But what I did notice is this: I got 1 of the leaves wet cuz I tried to wipe off the yellow spots, and the next day the whole leaf was yellow, dry and brittle. Because the water drys too fast on the leaf under the HPS or something, and cooks it, this is true, I have heard of this many times and seen it happen in both my last 2 grows.

The yellow spots in 2 weeks growth is new to me though, but I am convinced it's from some water droplets splashing on there and drying too quickly under the hps...

Because how can only 2 have a problem when they're all in the same space, same water, same nutes???

I am not saying your theory is incorrect, I just don't understand how only 2 can be showing symptoms if they all get the same soil and water.

[rainAgI4]

I just checked the pH of some water I used a few days ago, it has about 10-20% nutrients in it (of recomended).

The meter was saying 6.7

Since the last watering I havn't noticed any more yellowing, I have also made sure all leaves are dry after I water.

What should my water's pH be?

[rainAgI4]

Well this sucks my apt has black mold so I gotta relocate for awhile, same with my babys

I'll be back with updated news