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blotchy yellowing leaves on pepper plants

Posted by dlboone indoor (My Page) on
Sun, Jan 6, 13 at 11:41

Hi all,

First post here. Hoping this works...

I've started growing pepper plants indoors (Jalapenos, bell peppers, etc.) using a 400W MH light and a 400W HPS light source.

My first battle has been with fungus gnats. I found a post that recommended crumbling "mosquito dunks" and sprinkling the crumbs on the soil. That in combination with fly ribbon has helped, but just started about a week ago.

My question is about a couple of my pepper plants. Their leaves are turning yellow, not all at once, but in a blotchy pattern. Has anyone seen this? Any ideas what could be causing it? Is this root-rot?

Thanks in advance,

Follow-Up Postings:

RE: blotchy yellowing leaves on pepper plants

to avoid the fungus gnats.. sterilize all your media before planting ... see link

and get better control on letting things dry out a bit more ...

do you have this pot in pot.. whats the small circle near the trunk??? .. i never had very good luck with peat pots ...

whats the scale on this pic?? .... its either huge compared to all behind.. or supreme closeup ...

whats the research on using mosquito dunks on edible food plants????

are you hoping there are no residuals ....

i will let someone else talk about the yellow ...


Here is a link that might be useful: link

RE: blotchy yellowing leaves on pepper plants

No problem w/ mosquito dunks as they affect fly larvae not plants.

Beyond that, we need more info, including the following:
- What are you using for potting mix? In what size pots?
- What fertilizer, if any, are you using? And how often? And at what dose?
- What lights are you using?
- Number of hours lights are on each day?

Then please add anything else you think might be pertinent.

RE: blotchy yellowing leaves on pepper plants

A problem with Fungus Gnats begins when the soil the plants are growing in is kept too moist. Yellowing of plant leaves, Chlorosis, can also be caused by soils that are too wet because the plants are unable to uptake necessary nutrients. Plants need moisture to uptake soil nutrients but too much can also prevent that uptake as well as excluding the air that plant roots also need.

Here is a link that might be useful: Chlorosis

RE: blotchy yellowing leaves on pepper plants

i figured chlorosis.. but wasnt sure ...

but my question about the peat pot.. in the larger pot.. is still key ... [and i understand i am speculating.. as OP has not responded to this conjecture]

when you have two divergent media types.. as in here with pure peat in the peat pot.. and NOT in the surrounding media ... you have 'designed a problem' .. in that each holds and drains water differently ... so one might be sopping wet.. and the other.. reasonably dry ... and the plant can not cope ....

your seedling media.. and your eventual potting media. .. must be engineered to work together ...


RE: blotchy yellowing leaves on pepper plants

Thank you for all the helpful feedback!!

I'll read up on Chlorosis more. I did have problems with yellowish leaves on some Basil so I started adding magnesium to the soil (via a light sprinkling of Epsom Salt on top of the soil) and that helped a lot.

Soil is Miracle Grow garden soil.

I water them using tap water but I adjust the pH to around 6.5 or a little higher but less than 7.0.

Roughly every other week I have added individual packets of dissolving Miracle Grow fertilizer to the water (1 packet per gallon). Once about 2 weeks back I added a teaspoon of Epsom Salt per 1 gallon of water that I used to water the pepper plants, too.

The plant in the picture was grown from seed in that peat pot, then the entire peat pot was put in a pot just a little smaller than a 3-gallon nursery pot (with drain holes on bottom and sides).

I have noticed that most of the plants I started in the peat pots are much smaller than plants I started in plain old solo cups. Interesting comment from Ken on the difference in water drainage. It's possible I've been drowning them by watering inside the peat pot too much. I'm done with peat pots!

I'm using two iPower 400W light kits. (See link.) In one kit I'm using the Metal Halide bulb and in the other kit I'm using the High Pressure Sodium bulb. The plant in the pic was almost directly under the MH light, roughly 3 feet away from it; and diagonal from the HPS light, roughly 8-10 feet from it, and slightly shaded from the HPS light by another plant. I keep the lights on 16 hours per day using a timer.

I try to keep the temperature in the room at 76 degrees F, but since the fungus gnats started multiplying heavily I've kept the door closed (thermostat outside room) and the lights put off so much heat that I opened a window. Temps have been around 75-85F during the day and on the nights I forget to close the window as the lights turn off, temps drop to probably 50-65 F.

Yes, I have probably been keeping them too moist, watering every day, and watering directly inside the peat pots.

For reference, the Mosquito Dunks' active ingredient is a bacteria called Bacillus thuringiensis subspecies israelensis (BTi) that kill the larvae of a few Dipterans including mosquitos and fungus gnats. An EPA report states that BT is naturally occurring and has been in widespread use for over 30 years with no confirmed reports of health concerns (except to honey bees and Daphnia (water fleas), which I don't have - or want - inside my house ;). I'd have to look up the URL, but I also read that BTi can be used without losing "organic" certification status.

Is chlorosis reversible or should I terminate the few plants that show these symptoms?

A few more pics:

Thanks again!

Here is a link that might be useful: iPower light kit at Amazon

RE: blotchy yellowing leaves on pepper plants

Hi & welcome to Gardenweb!

"The plant in the picture was grown from seed in that peat pot, then the entire peat pot was put in a pot just a little smaller than a 3-gallon nursery pot (with drain holes on bottom and sides)."

If you stop using peat pots you will have much better results, or at least I have. Moisture will not cross that barrier properly. Trying to tear those pots away usually results in disaster and unnecessary stress on plants.

When you put a tiny root ball in a huge pot, especially absent the heat and sun of summer, problems can occur. That pot looks like it could probably go for weeks before it dried out, that's not good. Whenever it's taking more than a few days for a plant to dry out, root rot and other problems can occur. When you add fertilizer, it's going to concentrate in areas where the roots haven't permeated yet. I can't tell if your plants are chlorotic or burned from fertilizer - either too strong, or by building up in the surrounding soil.

The mosquito dunks should be dissolved in water, then applied (when the plant is thirsty.) I don't know anything about using it on food crops or not.

RE: blotchy yellowing leaves on pepper plants

It's possible I've been drowning them by watering inside the peat pot too much. I'm done with peat pots!

===>>> BINGO ... BANGO.. I WIN AGAIN ...


carp.. sorry about the caps ...

just happen to have some pix in my PB acct .. see below for your perusal ... 6 0z solo cups with 3 razor cuts on the bottom edge...

you might also think about up-potting.. to 8 and then 16oz cups..

that leap to 3 gallons ... is a waste of media.. and can really set back a babe ... i dont know why.. but it does ...

my theory.. was the pure peat.. in the peat pot ... its too acidic.. and that drainage issue ...

why would you terminate.. an experiment??? ...

IMHO.. you can do MUCH BETTER.. than miracle grow media .. find the nearest greenhouse [not many left] .. and ask them to sell you one of their giant bags of PROfessional mix ... insist on a dry bag.. and store it in a clean plastic garbage can ... a 5 year supply.. probably at what it cost you for a few bags of the MG carp ....

think of it this way.. you have a state of the art light system... and wallyworld media.. whats that all about ...

the pro's know how to manage water.. in the media.. it is.. engineered for such ... its not just a gelatinous blob of dark brown goo into which you hope to grow roots ...

media management.. is you next great leap on your learning curve ...

and dont forget.. TO STERILIZE IT ... from the get go ...

i dont have time to run out to the pole barn.. to tell what the 50# bag was.. i bought in fall.. send me an email.. should i forget for a week.. lol ...

great on the mosquito dunks.. i didnt have time to look it up when i wrote that post ... but never forget.. PREVENTION rules ... there is no 'fixing' the plague of the gnat ... [though i have some vague recollection of the dog getting fleas.. and a flea bomb cleaning out the gnats.. but that was 20 years ago ... lol ... but one thing for sure.. it is NOT a temp issue.. i dont know why you think that matters ...

i gotta run.. [read that.. hit send w/o final edit] .... gnats .. in the life cycle ... 3 types. ... those flying around.. eggs.. and larvae ... you have to kill all 3.. for a month.. to get rid of the problems... figure out how ....





and since you are interested.. lol... a rooting chamber ... on top of my science work station .. lol


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