looks like cold damage to me ... keep clicking the image until you get a super close up ...

it appears .... that there was individual plant cell damage with near freezing temps ...

one might wonder how you established 38 degrees... was the thermometer at the warm end.. or the cold end ...

i think you already diagnosed your problem.. when you noted that the problem is at the end.. furthest from the heater ... its apparently much colder down there...

having never run a greenhouse.. if you cant increase heat.. can you increase air movement????

ken

{{gwi:2524}}

Ken,

Thank you for your response. At this point I think that the best answer would be if it was, indeed, the cold. If it is my potting soil then, well, I have a problem. I have eight pallets of it sitting in my yard right now.

The thermometer was centrally located in the greenhouse on that very cold nigh. There is a good chance that that end of the greenhouse got colder.

I *can* increase the heat, I am just hoping that I don't need to. Propane is not cheap right now and that stupid money tree I bought off of eBay has yet to produce a yield. I may try putting a fan in there to increase circulation on the next cold night we have.

We are testing our soil and growing conditions right now and hoping to pin down the exact cause.

If anyone else has any other input, it would certainly be appreciated. Thank you for your time.

Your second picture looks like severe iron deficiency. I guess you could give them a little iron, and see if they perk up. Make sure it is just a little. Too much iron can be toxic (phytotoxic in the case of plants.)

But in case it isn't a nutrient problem, try to eliminate soil-borne diseases. Carefully remove one or more of the plants from the pot, shake off the growing medium, and inspect the stem at the soil line for signs of stem rot, either bacterial or fungal. And inspect the root system. Try to determine if the roots are alive or dead. If the roots are dead, then the plant is obviously dying and done for. If the stems and roots of the sick seedlings are alive, then an environmental or nutrient problem is a possibility.

Incidentally, just because you "are not dropping dead when we walk in" doesn't mean the heater couldn't be behind the problem, possibly by not keeping the greenhouse warm enough. Make sure your heater is getting actual propane, and not a mix containing some butane. Butane is bad for plants. You might want to check with your County Agent on this problem.

ZM

Zenman,

Thank you for your reply. Attached is a picture of one of the pepper plants that was also out in the greenhouse with the petunias. As you can see, all of the leaves have fallen off. However, inspecting the stem, there are no signs of discoloration or weakness, The roots are white and seem to be in good shape.

two things...

first.. at your photo site.. at the very bottom right.... it says ... GET EMBED CODES ...

copy the HTML code... and paste it right where you type.. on preview.. if you see it.. we will see it ...

second ...

you dont have to turn up the heat.. the close end proves such ...

you need to MOVE AIR ...

what about two box fans .. in the middle .. one to each side... facing each direction.. to create a circular air pattern ... i think thats the definition of circulation.. lol ...

zenny is prime on seed growing.... but those look like good roots to me ... with what??... 95% of your crop being good.. i would be leery to go changing much of anything ....

you used new media.. yes???

if recycled ... that could be a problem.... but the location thing begs to differ...

that was a third thing.. so i ..

wish you luck

ken

Thank you Ken. I didn't know that GardenWEB allowed embedded HTML. I will remember that for future use.

I don't think the pictures are really showing the extent of the damage. I only wish it were 95% good :(

The greenhouse is set up the same way it was last year but, I'm willing to embrace change. Circulation fans were on my to-do list for this year anyway, I guess I will just be getting them a little earlier.

The media is all new, no recycled potting soil.

ZM and Ken, I strongly feel you are correct.
My young petunias last year were all over the yard. Suddenly I would get one like the ones you show. They would just die. I freaked thinking this would spread. I carefully pulled each plant that was affected. The adjoining plants continued to grow. I determined that some petunia seedlings were genetically resistant to the Phytophthora virus attack.
Something that has stuck in my mind every since I read it years ago on the Wave Petunia site. It said never plant petunias in the same bed the following year, rotate because of disease. I haven't; I get some that get attacked; the rest flourish.
Another interesting observation for me this year:
The seedlings this year have weathered freezing temperatures (not a prolonged deep freeze) without being cover.
Regarding the peppers, I get that also. For me it is the soil disease: Phytophthora blight. Similar thing that kills the petunias (Phytophthora nicotianae)