Can anybody tell me what this is please?

[Ryandep6]

Can any one tell me what this is please?

 

[Mothman]

Looks like the initial symptoms of Mg deficiency to me, but there are some other possibilities.

Are you using Epsom salt or a cal-mag product?

 

[Ryandep6]

No im only feeding coco a and b atm, plant is 25 days old, its a autoflower, 16hours on 600w. Light is 20inches from canopy

 

[Ryandep6]

Looks like the initial symptoms of Mg deficiency to me, but there are some other possibilities.

Are you using Epsom salt or a cal-mag product?

No im only feeding coco a and b atm, plant is 25 days old, its a autoflower, 16hours on 600w. Light is 20inches from canopy. Its only the one lower leaf like this

 

[BigBlonde]

My first thought was an Mg deficiency. My second thought was slight light stress that can show on lower leaves first, due to them being older. Supplementing with Epsom Salts or Cal-Mag would be a good bet.

 

[Mothman]

My first thought was an Mg deficiency. My second thought was slight light stress that can show on lower leaves first, due to them being older. Supplementing with Epsom Salts or Cal-Mag would be a good bet.

Yup. It fits. Strong LED hanging close would do it. Plant can’t keep up with Mg demand at the top and pulls from the bottom leaves.

One of the old timers here adds 1/4 tsp of Epsom to each watering/feeding, so I adopted that approach. Seems solid.

Edit: And maybe back away the light or turn down the power a tad. Watch your remaining leaves to see if the symptom worsens.

 

[Ryandep6]

Yup. It fits. Strong LED hanging close would do it. Plant can’t keep up with Mg demand at the top and pulls from the bottom leaves.

One of the old timers here adds 1/4 tsp of Epsom to each watering/feeding, so I adopted that approach. Seems solid.

So ahould i turn my light down? Get some epsom salt and start introducing that? Im currently feeding every 3 days, should i add the salt every feed or every over? Sorry im new to all this. Would you like any more pictures?

 

[Mothman]

So ahould i turn my light down? Get some epsom salt and start introducing that? Im currently feeding every 3 days, should i add the salt every feed or every over? Sorry im new to all this. Would you like any more pictures?

Personally I’d back off the light about 6-8 inches for a few days. Do you have it where the light mfr recommends for this stage?

Adding 1/4 tsp Epsom per gallon (every feed and water) is almost nothing, so shouldn’t hurt anything and likely will help. It’s more of a maintenance dose. The magnesium sulfate will provide Mg and sulfur in low doses—generally a good thing.

And yes, sharp pix of the whole plant helps to confirm.

I’m not familiar with your nutes and tried looking them up but the coco a&b name seems to be used by multiple brands. I assume your soil medium is a blend of coco and peat?

 

[Ryandep6]

Personally I’d back off the light about 6-8 inches for a few days. Do you have it where the light mfr recommends for this stage?

Adding 1/4 tsp Epsom per gallon (every feed and water) is almost nothing, so shouldn’t hurt anything and likely will help. It’s more of a maintenance dose. The magnesium sulfate will provide Mg and sulfur in low doses—generally a good thing.

And yes, sharp pix of the whole plant helps to confirm.

I’m not familiar with your nutes and tried looking them up but the coco a&b name seems to be used by multiple brands. I assume your soil medium is a blend of coco and peat?

Its plant magic, thats the brand. Just coco. I turned the light up monday and this appeared today, so im guessing its the light.

 

[transient.bean]

This chart may be helpful in the future

 

[Mothman]

Its plant magic, thats the brand. Just coco. I turned the light up monday and this appeared today, so im guessing its the light.

Ok thx. I’ll look for that bottle. Do you have a smartphone with a par meter app? It’d be good to have an idea how much or how little light they’re getting in each stage.

A bigger concern may be your watering. I’ve never grown in pure coco but I’m told it’s normal to water it daily and even 2x a day! Tell us about your watering—how much, size of pot, how frequent, runoff if any.

Your nutes claim to have an increased level of calcium, so get some concurrence from a more experienced grower before dumping in more Ca via calmag. But the Epsom advice (for Mg) stands. You can get that for cheap at any pharmacy or grocery store.

 

[BigBlonde]

I turned the light up monday and this appeared today, so im guessing its the light.

LED light intensity and the plant's magnesium needs are related. My understanding is that cannabis needs more magnesium when grown under LED lights than when grown under other types of lighting. So, the problem is not just the light or Mg. It's both.

 

[Harpua88]

Coco......a & b ?

What does that mean?

Do we know why LEDs tend to give plants this problem? And is Epsom salts the best thing to add? Is there something better?

 

[memnoch]

Can any one tell me what this is please?

I noticed one of mine is doing the same thing today. It is in plain miracle grow and the others are in better stuff. Bigblonde is correct, It's both the led being to close and magnesium from it being to close. Mine was way closer than the manufacturers recommended. hope raising them fixes this for both of us.

 

[Ryandep6]

Ok thx. I’ll look for that bottle. Do you have a smartphone with a par meter app? It’d be good to have an idea how much or how little light they’re getting in each stage.

A bigger concern may be your watering. I’ve never grown in pure coco but I’m told it’s normal to water it daily and even 2x a day! Tell us about your watering—how much, size of pot, how frequent, runoff if any.

Your nutes claim to have an increased level of calcium, so get some concurrence from a more experienced grower before dumping in more Ca via calmag. But the Epsom advice (for Mg) stands. You can get that for cheap at any pharmacy or grocery store.

Thats both my plants…

 

[Ryandep6]

Coco......a & b ?

What does that mean?

Do we know why LEDs tend to give plants this problem? And is Epsom salts the best thing to add? Is there something better?

Im in the uk. Feed brand is pant magic coco a and b 2 diff bottles

 

[Ryandep6]

Also im not using led. Its hps 600w

 

[Harpua88]

Im in the uk. Feed brand is pant magic coco a and b 2 diff bottles

Ah......it seemed like there were 2 different kinds of coco coir itself. You're referring to a nutrients product.

 

[Harpua88]

Also im not using led. Its hps 600w

Another Ah.......a 600w High Peessure Sodium.....

Years ago I used a Metal Halide. The vommon belief was that Metal Halide was for growth, High Pressure Sodium was for flowering. If you could grow with a Halide and add HPS into flowering that was the best.......one could grow and flower with only Metal Halide, and, one could grow and flower with only HPS.........

But......now I'm just digging in to my way back old memory banks, of which I've made a lot of withdrawals.... ;). But I think I remember reading that using only HPS for the veg cycle wasn't the most ideal spectrum, and maybe it could lead to some minor nutrients issues....

 

[Crabgrassfarms]

I had a similar problem early on, just noticeable, so I introduced cal/mag to my watering and it went away. However, I grow in organic dirt so your results may be different.