Interesting. I hadn't noticed any thrips around (not that I'm totally sure I could identify them), but there haven't been any insect infestations that I'm aware of. Today, there was a single white fly and what may or may not have been an egg on the leaves (which I removed). I'll try and get a decent picture tomorrow. Any sort of damage control I can start right away in the morning? Thanks for your help.

Thanks for the additional info. First, the mix you are using is not condusive to success with seedlings. Compost not only compacts in containers, drains poorly as you have discovered, but provides no nutrients to the plants because there is no active soil micro herd in the mix to aid in the decomposition or convert the nutrients in it to a form usable by plants. Compost and small containers just don't jive with each other well. Add to that the sparse root development you have seen and "water-on-schedule-need-it-or-not" approach and you have the answer to the condition of the plants - the mix you are using and the over-watering. I don't know why you elected to use the mix you did rather than one of the many classic soil-less growing mixes but you have unfortunately learned the hard lesson we all had to learn at one time. If you are inclined to transplant your plants yet again into a quality soil-less potting mix, water them only when the soil 1/2 way down is dry to the touch, and set up a weekly feeding schedule of a 1/2 strength diluted well balanced fertilizer they will improve quickly. What everyone who seems to be devoted to only organic nutrient sources needs to understand is that without an active soil web of beneficial bacteria, which don't exist in any container unless you add them, granular and non-liuid forms of organic fertilizers cannot work. Either switch to one of the many liquid organics or go with one of the synthetics and save the organics for after transplanting. I understand the problems with temp control in greenhouses after my years in the nursery/greenhouse business. Unfortunately developing a way to control it is vital to plant health as either extreme is harmful to them. Automated systems are the ideal of course but many can't make that investment. But that doesn't mean you cannot and should not prevent the 100 degree days. Ideal minimum is 45, ideal maximum is 65-70. Increase your venting, employ shade cloth, add a box fan for exhausting hot air and pulling in fresh cooler air, increase the air humidity levels, etc. are just a few of the temp control measures available. Much more info is available on the Greenhouse forum here. Hope this helps. Dave PS: As any experienced grower can tell you, rootbound plants, no matter where you might see them or how they may appear to the eye, are never healthy plants. But that apparently isn't the issue here anyway.

" I actually think it's when true leaves are adapted to the lower radiation levels of artificial indoor light that the plant becomes prone to sun damage. I would guess that, as soon as the growing tip starts producing the first indications of true leaves, that's when you have to start being super careful about sun damage." I'd agree if for no other reason than the cotyledons alone aren't capable of photosyn, only the true leaves. But many times that distinction isn't included in the advice. Shoot I have lost trays of young seedlings sitting in the greenhouse from sunburn, much less outside. What I take issue with is the broad statements made on so many blogs. Utube and even sometimes here, that putting your seedling out in full sun is no problem - no guidelines, no qualifications, no age guidelines, no distinction between full sun in AZ vs. full sun in MN, etc. Newbies read those claims and next thing you know they have a tray full of sun and wind burned plants or dead ones and want to know what happened to them. There is a thread running on this right now over on Vegetable Gardening with pics of young seedlings that were put outside early on and the damage that happened. So the safest approach is to not do it unless you are experienced and really know what you are doing and if you are going to do it be prepared to possibly lose some of your seedlings. If you have 200 of them it is no big deal but if you only started 10-12 plants it can literally wipe you out. But people get impatient and they don't want to bother with proper hardening off procedures. Their choice but they have to pay the price. Dave

Thanks for taking a look! I originally planted them in this seed starting mix in this 72-cell flat. They were on a heating mat controlled by a thermostat, set to about 83F. Once they had their true leaves, I separated the seedlings (I planted multiple per cell) and transplanted them into this Vigoro potting mix in square pots that were 3.5” across and 5” deep, and took them off the heat mat. Before this initial transplantation I saw that some had yellowish leaves. I thought that perhaps they didn’t like the heat mat now that they had germinated, and I hoped that transplanting them (and getting them off the heat mat) would help. However, the yellowing got worse. I fertilized the yellow seedlings with very dilute Miracle-Gro 15-30-15 (1/2 teaspoon per gallon of water) and put a fan on all of the seedlings. Around this time I posted this question. The consensus there was that the potting soil was holding too much moisture (I hadn’t noticed that it was advertised as retaining moisture), so I re-transplanted them into this Miracle Gro potting mix. When I re-transplanted them I also put them into smaller pots (about 3” across by 3” deep), so that they would dry out faster. Over the course of a couple of weeks the yellowing went away. Backing up: before the re-transplanting, some of the seedlings had purple undersides and mild twisting of the leaves. (The Cherokee Purple seedlings definitely had this; I’m not sure which others had it.) It didn’t seem to be causing any problems, though, so I didn’t worry about it. When the curling got worse, I thought perhaps it was left over from being too damp, and hoped that it would get fixed by the re-transplanting like the yellowing got fixed, but the twisting/curling has gotten slowly worse. The Cherokee Purple seedlings did not get the initial fertilizer, since they weren’t yellowing. However, the Omar’s Lebanese and Brandywine probably did get the fertilizer, since they were yellow. So there doesn’t seem to be any correlation between these seedlings and the ones that were previously yellow (and previously received dilute fertilizer). The only pattern I can see right now is that it follows the variety: if one seedling of a variety is affected, all are. A couple weeks after the initial fertilization, I fertilized all of the seedlings, again with the same dilute fertilizer. A week or so after that, I watered all of the seedlings with 1 tablespoon of Epsom salt per gallon of water, in case the magnesium would help with the purple leaves. This was only a couple of days ago, which is why the potting soil is still damp in the photos. The Epsom salt may have helped with the purple coloration, but it hasn’t helped the twisting so far. The seedlings aren’t near a window. We’ve had the heat set at 66F, and it’s been pretty consistently that temperature inside except for a few days recently when it’s gotten closer to 80F. The twisting started before those hot days, though. As mentioned, I had a fan blowing on all of the seedlings, but I stopped that about a week ago in case it was somehow causing the twisting. So far stopping the fan hasn’t made a difference. I think I’ll turn it back on to help the soil dry out faster again.