What causes this rusting?

[Naturalx]

Hey,

So my one autoflower is very slowly flowering compared to the rest but is developing some serious rusting on the leaves.

I’m about to feed them. Curious what could be causing this?

 

[Mr Bee]

It kinda looks kinda like heat or possibly wind burn.is it near either a hot light or a fan?

 

[Naturalx]

It kinda looks kinda like heat or possibly wind burn.is it near either a hot light or a fan?

Nope, it’s about 75f and the fan in there is on low and not pointed at this. I had it before in a plant and it continued to get worse and that one had a hollow main stem assuming from lack of cal mag

 

[Jimster]

Some strains have hollow stems, so that shouldn't be an issue. I've seen that type of damage from higher humidity and foliar feeding, where the water gets trapped between two leaves and the damage appears at the main points of contact (on top of the leaf ridges). No chance of spider mites, right? They can cause damage somewhat similar to this, but there are usually tiny red dots on some of the larger fan leaves in addition to the rusting. The damage probably happened at least a week or 10 days ago... it can take that long to appear. Deficiencies can cause some issues as well, but this doesn't look like a deficiency or an overdose, at least to me. What medium are you using? It's kind of hard to tell from a single photo of a leaf, but it is probably OK. I'm not one for pouring stuff on a plant to try to counteract something else that was put on the plant previously, but maybe a dose of foliar applied cal-mag might help. The leaf looks non-specific to me, so I'd just let it grow and see what happens rather than trying to figure out what, if anything, that you did to it.

 

[Seraphine]

What’s your pH when feeding and watering?

 

[Naturalx]

What’s your pH when feeding and watering?

I am growing in coco and start my ph in a lower range 5.8-6.0 and then raise it as it gets into flowering usually 6.3-6.0.

Due to where my plants are currently located I am unable to feed daily. So maybe they are receiving too little nutrients in my schedule as is, and with the delay in days it is maybe advancing this problem further

 

[Naturalx]

Some strains have hollow stems, so that shouldn't be an issue. I've seen that type of damage from higher humidity and foliar feeding, where the water gets trapped between two leaves and the damage appears at the main points of contact (on top of the leaf ridges). No chance of spider mites, right? They can cause damage somewhat similar to this, but there are usually tiny red dots on some of the larger fan leaves in addition to the rusting. The damage probably happened at least a week or 10 days ago... it can take that long to appear. Deficiencies can cause some issues as well, but this doesn't look like a deficiency or an overdose, at least to me. What medium are you using? It's kind of hard to tell from a single photo of a leaf, but it is probably OK. I'm not one for pouring stuff on a plant to try to counteract something else that was put on the plant previously, but maybe a dose of foliar applied cal-mag might help. The leaf looks non-specific to me, so I'd just let it grow and see what happens rather than trying to figure out what, if anything, that you did to it.

Growing in coco, using general hydroponics nutrients micro and bloom as well as cal mag. I’m going to up the calmag and see if that has any indication. It is also showing a nitrogen deficiency in new growth. This auto just won’t quit growing in size. It pre flowered and is still just putting on size

 

[Seraphine]

I grow in coco too. Make sure when you skip a day you get a lot of run off when feed/water next to flush the salt build up out. I would also cut back on the nitrogen a bit. What are you feeding them? Are you feeding every time you water? Some plants like a higher pH, even in coco. I keep my pH around 6.2 even in veg, every now and then I’ll drop it to 6.0 or 5.9

 

[Seraphine]

I am growing in coco and start my ph in a lower range 5.8-6.0 and then raise it as it gets into flowering usually 6.3-6.0.

Due to where my plants are currently located I am unable to feed daily. So maybe they are receiving too little nutrients in my schedule as is, and with the delay in days it is maybe advancing this problem further

Can I see a pic of the whole plant under normal lighting? That leaf you posted looks really green which makes me think you’re nutrient levels Are too high. I would adjust you’re pH before increasing nutrient strength. If anything reduce nutrients and up your pH to 6.1-6.3

 

[Kingjoshh]

Hey,

So my one autoflower is very slowly flowering compared to the rest but is developing some serious rusting on the leaves.

I’m about to feed them. Curious what could be causing this?

Have you been spraying anything on it, looks like when I leave water on my leaves

 

[Naturalx]

Have you been spraying anything on it, looks like when I leave water on my leaves

I was spraying water weeks ago to keep humidity up but not for two weeks.

 

[Kingjoshh]

I was spraying water weeks ago to keep humidity up but not for two weeks.

Then check soil acidity, good luck !

 

[Naturalx]

Can I see a pic of the whole plant under normal lighting? That leaf you posted looks really green which makes me think you’re nutrient levels Are too high. I would adjust you’re pH before increasing nutrient strength. If anything reduce nutrients and up your pH to 6.1-6.3

I will get a photo next time I am there. I have not done any plain water flushing at all. In my previous plant that had this happen it got aggressively worse during the final flush as well.

 

[Naturalx]

Then check soil acidity, good luck !

Maybe my ph pen could use a re adjustment.

 

[Seraphine]

Possibly. Try putting just a little less pH down. It doesn’t take muck to make a difference with that stuff. Are you still using all three GH flora bottles during flower? If so, cut out the grow and stick with the micro and bloom during flower. When you let coco dry out, salts build up on the roots. You need to make sure to get plenty of run off the next time you water/feed when you miss a day. I am guilty of skipping a day too.

 

[Seraphine]

I used to use GH flora but now I use masterblend dry will never switch back to liquid nutrients again. You still have to mix the masterblend with water but I am getting awesome results with that stuff and it is so much more budget friendly!

 

[Naturalx]

I used to use GH flora but now I use masterblend dry will never switch back to liquid nutrients again. You still have to mix the masterblend with water but I am getting awesome results with that stuff and it is so much more budget friendly!

Because I’m growing in plastic pots over fabric the coco doesn’t seem to dry out like it used to so I don’t water every day. When I get them in my house I will be. But I can make the trip every day to water them right now. I’m just waiting on a few things to get finished up in my new place so I don’t need to worry about maintenance coming in

 

[Naturalx]

I do

I used to use GH flora but now I use masterblend dry will never switch back to liquid nutrients again. You still have to mix the masterblend with water but I am getting awesome results with that stuff and it is so much more budget friendly!

not use the grow at all actually. Never have.

Right now I’m watering at 4ml micro and 8ml bloom per gallon. I have switched to Gaia green outside but because I didn’t mix it up very well one plant I can tell just wasn’t getting the nutrients and the colors was very light. They are also lagging about a week behind where they should be possibly because the weather isn’t optimal I might just start them over.

 

[Seraphine]

Because I’m growing in plastic pots over fabric the coco doesn’t seem to dry out like it used to so I don’t water every day. When I get them in my house I will be. But I can make the trip every day to water them right now. I’m just waiting on a few things to get finished up in my new place so I don’t need to worry about maintenance coming in

That makes sense. I really like fabric pots, no issues with rootbound or root root/overwatering.

 

[Naturalx]

That makes sense. I really like fabric pots, no issues with rootbound or root root/overwatering.

Me too. I wanted to give plastic pots a try for training autoflowers I find it significantly easier but it doesn’t appear to dry out nearly as quick and as nice.