Hi Danielle,

Well, it's hard to tell. It could be some kind of disease like blight or gray mold. Mold could be caused by over-watering, damp conditions, and/or lack of good air circulation. If it is some kind of disease, it's going to be hard to stop it. Prevention, rather than cure, is usually suggested.

I'm wondering if it could be as simple as a lack of potassium. You said you fed the plants with a diluted fish emulsion. Is that the only fertilizer you used? Fish emulsions are relatively mild fertilizers and usually quite low on potassium (5-1-1 or maybe 5-2-2). You might want to try fertilizing with something like diluted Miracle-Gro Tomato Plant Food (18-18-21). It also contains many micro elements like Magnesium, Copper, Iron, and Zinc.

Sorry I can't be of more help,

Art

Yes, that's the only fertilizer I've used at this point. Similar to what I would typically do with outdoor seedlings....my cucumbers, melons and moonflower always went bananas when I did this, although I usually did full strength since they were older baby plants.

I really do not think that overwatering is the problem in my case, however circulation might be. I have yet to add a circulation fan which I said I was going to do from the get go and did not. I'll pick one up next time I'm in town.

Should I be plucking the diseased leaves to prevent spread to other leaves, assuming this is not a systemic problem? Again, I didn't know what impact plucking any leaves, even infected ones would have on plants this young. They all have true leaves at this point but some only 2 or 3 depending on the crop.

I can try the diluted miracle grow next time I fertilize and see if there is improvement. They are planted in a mixture containing potting soil (as well as sphagnum peat moss and some perlite added for aeration). I assumed there were some nutrients present in the potting soil but perhaps not enough, it was not a high quality one.

How often should I be fertilizing? Weekly? Every couple of weeks?

Thanks for any input.
Danielle

Danielle,

Regarding the question of whether or not to remove the affected leaves, I don't know. The problem is that we don't really know what's wrong with the leaves :-) Personally, I'd probably remove them, but that's just me.

How often to fertilize? The problem there is that we don't know whether or not your potting soil already contains fertilizer (or how much). At least for awhile (and while the plants are that small), I'd probably mix the liquid fertilizer at about one forth (1/4) strength and use it every time I watered the plants. If things improve and as the plants grow larger, you could gradually work up to what the manufacturer recommends (every 7 to 14 days full strength during the growing season).

Art

I know it may be too late by now, but that looks a lot like fertilizer burn from too much of it, too strong.

Hey all,

I'm still not sure what the diagnosis is/was. I did remove the affected leaves before our trip and watered well. The lights were on a timer for 16 hours a day while we were gone and the plants look healthier now that we're back. Maybe I should go on vacation more often lol.

Susan, thanks for the reply. You could be correct, I just don't know. But I wouldn't think fish emulsion at half strength would burn them.

I did not have a chance to try the miracle grow before I left in case it was that they weren't getting enough nutrients. Now that we're back I've repotted most of them today and will try miracle grow or something of that nature next to see how they respond. Again this is my first attempt at this so maybe I am wrong, but they do seem small to me for 8 week old plants. Of course letting them dry out too much set them back I'm sure.

They also were moved out into the greenhouse a couple of days ago and they also seem "perkier" in the cooler temps since doing so. Again as a first timer I'm not sure if this was a smart thing to do or not but I need to make room on the indoor light rack for some ornamental seeds. I've observed daytime winter temps in there up to 85 and nighttime usually stays 40-50 with the wood stove on below freezing nights. The sunlight does concern me though so I'll have to monitor them.....I have not yet set up any supplemental lighting out there and this time of year the daylight may not be sufficient to keep them growing well.