disease Dark spots on leaves

[knidik]

Hi,

I'm currently growing habanero chocolate. I have some plants outside and some inside.

Outside plants are doing great. Its currently about 25-29C and 70-80% humidity outside.

Inside though it's a bit more tricky. Temp is 25C and humidity ranges from 30% to 65% (AC turned on and no humidifier).
Bottom leaves of the inside plants are developping brown spots and turning yellow. I'm growing in biobizz light mix soil, adding 2ml/L of biogrow and started adding calmag since I know water here is soft. New growth is fine.

I'm guessing that since the only diff between inside and out is the humidity, that's probably the issue. But then again what do you all think ?

Thanks a lot

 

[CaneDog]

Hey, knidik.

That looks environmental. I don't think your heat or humidity is the issue, but if so it would most likely be too much humidity, not too little. Soil composition and proper watering are the most likely culprits here. It sounds like your container soil is a good one (I haven't used that before, but recognize the name), so watering is probably what to focus on. As easy as proper watering sounds, it's not always easy as there are many variables that can get involved.

I can see cupping/canoeing in the leaf in the upper left of the picture. That supports that the roots aren't as happy as they could be, often either a congenital root issue or the soil is holding too much water too much of the time.

I suppose there could be fertilization considerations too, but I can't see enough of your grow to get a better idea. I suspect though that if the condition of the soil is good and with proper watering - especially letting them get reasonably dry before re-watering - the plants should be doing well without much in the way of supplemental nutrients.

 

[knidik]

Hi,

Thanks a lot
I am letting them dry out before i water again.
I do have springtails in most pots (they are still alive even though I let it dry out before watering again). Might that be the issue?

Thanks again!

 

[CaneDog]

Great pictures of your peppers! They look in good shape - the outdoor ones especially! Those are still cupped a little, but they're reaching up suggesting they're quite happy now. They'd probably benefit from bigger containers soon.

The indoor ones have droopy leaves with some misshaping. They don't seem in any immediate danger, but they look like they've been in damp conditions too much. Letting them dry out well between waterings and watering thoroughly is how I would address that. In fact, I'd probably go a step further and repot them, removing the extra soil around the main clump of root ball and getting them into fresh soil, perhaps with a simultaneous pot-up. That's probably not necessary, but I typically re-pot in these situations because I want to get the roots exposed and in contact with new soil right away.

I haven't had to deal with springtails before. My understanding is they like wet conditions and some varieties will chew on roots. They might contribute to the problem. Hard to say. Greater support that they've been a little too wet if they're in the mix, though.

 

[knidik]

Yep they stayed in the humidity dome a while since I had issues in the main room. I'm drenching the soil to get rid of them, and after that i'll let it dry out, transplant, and water well.
Thanks for your advice, it's much appreciated !

 

[knidik]

Hi, little update. So new leaves are a bit greener but they seem to be yellowing from the outside in. They’re not dropping as much as before. The yellowing looks to me as a deficiency. It’s starting from the bottom so I’d guess a mobile nutrient like Mg. Water here is soft so I do add 1ml/l of calmag. Maybe a little bit of potassium deficiency too.
What do you think?
Thanks a lot

 

[CaneDog]

What it looks like to me is that the plants are cannibalizing some lower leaves for nutrients to support the new growth. I don't think your soil mix lacks proper nutrients. I read up on the biobizz light mix. Apparently, it's a medium-ec mix with organic components, so it should be adequate for pepper plants for a reasonable time. Likely, the nutrient deficiency is not in the soil, but is a result of the plants being unable to access/utilize the nutrients. This is common in circumstance where dampness is an issue. If it actually is a deficiency of the soil, a decent broad coverage fertilizer is often the best application, as it provides a balanced diet and you don't have to troubleshoot which specific nutrients to add.

My experience is that once the plant has started to mobilize a given leaf's nutrients, that process continues with the leaf being dropped, eventually (typically, the margins and interveinal areas of the older leaves are first affected, which is consistent with your pictures). So, if your plants had started to draw nutrients from certain leaves before you improved their conditions, they will continue to do so and the leaf will continue to look worse, despite that the newer parts of the plant are looking better. For this reason, I always look to the new growth in these situations to determine if the condition is improving, because the older growth may continue to look worse, despite.

What sort of light and light cycle are you running on these?

 

[knidik]

I’m using gavita 1700e running at 50% and 48in above canopy (that’s about 2-300ppfd) during the time they are recovering. I run them 16/8. Humidity isn’t an issue anymore vpd is around 1.2. New growth is looking better.

 

[CaneDog]

That all sounds positive. I would just continue to monitor the new growth.

 

[knidik]

Thanks a lot

 

[knidik]

Hi again

Update on the grows.
- Inside ones have flowered and one is even growing a pepper. I did start some new ones inside and they have the same symptoms as the first grow : starts well, then leaves start to yellow from the bottom and the edge of the leaves have brown spots. Just like the first grow. And I’m pretty sure I’m not overwatering (I let the soil get really dry and keep it that way 1-2 days). Plants aren’t wilting so I guess no underwater it either.
I moved a plant outside to see if it would get better : in one week it thrived. Leaves that’s were curled under started to flatten out and new growth can be seen. So this tells me it’s environmental. Only difference : humidity is 55-60% inside and 70% outside. Temps is 25-26 inside and out.
What could be the cause of this?

Thanks a lot

 

[CaneDog]

Hey Knidik. Sorry to hear you're still having issues. Looking at the plants, to my eye it still appears to be root issues caused by too much water retention and possibly related compaction of the soil. It's not just the deficiencies, it's the growth habit of the plants and shape/drooping of the leaves that gives me this impression. Once the roots are affected it's hard to turn them around by focusing only on optimal watering. However over time, if the condition isn't too bad, the roots will fill out the space in the container and better "control" the moisture level and the plant will often grow out of the condition. Moving a plant outside often helps accelerate recovery. The factors that come to mind as possible differences are natural sunlight, greater day/night fluctuations in temperature (and perhaps humidity), and better air circulation. For whatever reasons, natural outdoor conditions seem to fix a lot of problems.

When I'm trying to recover a plant quickly indoors, I do the transplant like you did previously and that seems to give me the best results. In a little more detail, I transplant when the plant is in a lower-medium level of soil dampness - very close to when I'd be watering again. I mix the soil in another container to where it is only slightly damp, definitely not wet. I remove extra soil around the root ball, then I carefully fill the container and transplant trying to minimize any compaction of the soil - minimal "patting down" of the soil - and I don't water after transplant because I want to make it as easy as possible for the roots to reach into the new soil which means loose soil with lots of air content between the partials. I'll even go so far as to water only slightly at the very base of the transplant for the next couple waterings, to keep the new soil as inviting and uncompacted as possible until the plant has established roots into the new soil.

I know I'm not providing much of a new opinion here, just more detail, but I haven't seen anything to change my thought that the soil is staying too wet and compacting early and that's retarding root development. Proper transplanting gives the roots a new start and, once they fill out the container, a plants seems to be able to better deal with watering and soil condition issues.

Maybe someone else can provide different insight. Hopefully you'll be able to get things back on track and have a happy grow.

 

[knidik]

Thanks a lot for your detailed response.
Thing is, this is only a test grow for the next one : I’m going to be growing medical marijuana for a research program. I have experience growing that (to me much easier than habaneros haha), but the grow room is new, and I’m terrified by the fact that it might be an environmental issue. Moving the plant outside and see it recover in a week did stress me out. While I wait for my cannabis seeds, I’ll follow your advise by transplanting on a bigger container and follow your guidelines. And just pray is recovers like outside.

Thanks a lot for the input,

Seb

Édit : just transplanted the small yellowing one which was starting to get rootbound. Didn’t water and made sure there were no pressure points so soil is loose. Keep you posted

 

[knidik]

Little update : seems like they’re doing better
Thanks for all the help !

 

[CaneDog]

Great to see those pods!