albjen, welcome to the forum. If you will go back to your profile and put in your location/zone information, people will have information to help. Without that, any response is a pure guess in the dark. Also, what is the soil, lighting, temperatures, watering pattern, etc. These are all needed to give you a quality response. Good luck!

Agree that MUCH more info is needed. The photo looks more like frost damage than scorch. But if all the different plants are affected then the cause is something they have in common - soil mix used, over-watering, some fertilizer used, etc.

The most common cause of seedling death is over-watering. No one thinks they are doing it but they are. But this is all just guessing without much more info.

Dave

Sorry I'm new.
The starts are indoors. I keep the room warm 75ish degrees. I have been watering them with tap water. I water them regularly. The starts were all doing fine until about a week and a half ago. What other info would be helpful to know?

I'll post a few more photos.

They are not adjusted to the sun. Keep them moist and keep them outside in partial shade.

Squash

lettuce

soil mix used, over-watering, some fertilizer used, how much and what kind?

Plus what type of lights are you using? T5, T8, etc.

The tomato plant photo shows clear nutrient deficiency so the soil mix used and fertilizer used question is very important.

And last - where are you located and what is your gardening zone? Note how in all the other posts they include their zone and location?

Dave

I see a possible nutrition deficiency there. POSSIBLE !

How and What are you feeding your seedlings ? What is your soil mix ? How often do you water them ? How do you water : from top or bottom ? How many hours of light ? and how close ?

Zone 4 South east Id

Jiffy Ferry Morse G316 Jiffy Organic Seed Starting Jiffy-Mix

My bulbs are Hydrofarm Dayspot CFL 26W/65K, 100W Eq.

I water when the soil is dry.

I haven't used any fertilizer. I'm happy to use organic but do not know what to use. I am very much a beginner.

I leave the grow lights on 24/7 is that bad? I water from the top.

One thing - that Jiffy mix is just for seed starting not growing. It is also noted by others on the Growing from Seed forum as having drainage problems. So first thing I'd suggest is buying a bag of one of the many good soil-less potting mixes and transplanting the ones that look salvageable into it.

Second, you are using peat pots. They are also well known as being problematic for several different reason - mostly because they encourage over-watering by making the soil appear drier than it really is.

Then, once plants develop true leaves they have to be fed - no matter what they are growing in (with a few exceptions). The only organic fertilizer that is somewhat effective in this situation is one of the many fish emulsion/kelp mixture liquids. There simply isn't any active soil bacteria in you mix to convert other organic fertilizers to a form usable by plants.

Organic gardening in containers, especially small ones is a totally different ballgame then growing organically in containers. There are many discussions here about this. So even those of us who garden organically will often use a diluted to 1/2 strength Miracle Grow of one of the similar brands for our seedlings.

Since you are using Hydrofarm high capacity bulbs I assume they are in Hydrofarm fixtures? If not then they sure should be. LOTS of heat from those. Unlike the standard cool white fluorescent fixtures they are NOT kept close to the plants as they can burn them. They have a 4' footprint and are normally kept 12-18" above the plants and no closer to avoid burning. So it is possible that is contributing to your leaf problems.

But the most likely cause IMO is poor soil quality, that it is a only a seed starting mix, they have been given no nutrients, and have been very likely over-watered and the roots are rotting causing the leaves to die. Your last pic is classic of those problems.

Dave

Thank you so much for taking the time to help. I'll get to work.

I also had a poor experience once with Jiffy and I have heard others say the same. So I never use Jiffy or peat pots. Is there also some evidence of mildew on the soil surface in a couple of those photos? I had some difficulties when I first started growing under lights and with a suggestion from someone, to add a fan to the mix, I've had a lot more success and fewer problems.

Sounds like a good idea to try.
No mildew. I may be having problems because I originally planted my seeds in peat pellets and then just stuck the pellets in the peat pots with jiffy. Perhaps that is a factor in root rot because they may be holding a lot of water in the pellet and I don't know it when I start watering.

Not to suggest that was your main problem, because the advice you've been given sounds right on the mark to me. Just as you are tweaking things, adding a fan is often suggested and I've found it helped a lot to keep things dry and keep the air moving. Especially when I was growing in the basement. It also helps make tomato stems sturdier.

I originally planted my seeds in peat pellets and then just stuck the pellets in the peat pots with jiffy.

This is new info and yes, it only compounds the water problems. Did you remove the netting from the pellets before putting them in the pots? Definitely need to do that.

Dave

My experience with peat pellets was that the roots of many plants weren't able to penetrate into the pellet. Even properly soaked they were too dense.

I was appalled at how horrible the roots were for most of those seedlings.