1. No dome or any other type of covering over the seedlings as soon as the seeds have germinated (sprouted).

2. Peat pellets are terrible, it is really hard to control their moisture.

3. Too much water

If they seem to be bending/wilting at the soil line or beneath the seed leaves you have dampening off disease. Look at the FAQs on this forum for help on saving them and/or the rest of your plants.

If they are not..

Replant in large pots (3" or so) with moist sterile soil. Keep the air temps 75-60 degrees, decrease water and increase artificial light and air circulation. And TAKE OFF THE DOME on all of our plants once germinated.

Make sure you remove the netting on all of your peat pellets because roots can not grow through them, the tips will be ripped off in the process but they should bounce back.

Keriann~

I agree with Keri that the most likely problem is they developed damp-off while under the dome. Dome is for germination only and simply must come off just as soon as the germinating seed breaks the soil surface.

Many of us never use a dome or any kind of plastic cover at all just to avoid this sort of problem.

The second most likely cause would be excessive watering causing overly wet soil and subsequently root rot and death.

Too much water kills more seedlings than anything else.

And for future reference when you get the chance you may want to browse through all the past discussions here on the many problems of using peat pellets and peat pots. Both should be avoided IMO.

Be sure to check out the picture in this discussion on root bound plants in peat pellets.

Dave

I use peat pellets, but I don't use the domes. You really need to keep
an eye on them. Anything with peat can dry out quickly. I think the
plants you transplanted were already too wet. You can take the dome
off and let the pellets air out.

The trouble with anything peat is that when it dries out it clumps in a solid mass that is hard to wet again. It simply runs water --like water off a ducks back to use a cliche.

Another problem with peat is that it is too acidic and can cause problems with alkaline loving plants. In addition when it gets too wet it holds too much water and plants damp off. I tried all different ways of planting and anything peat is on my never use list at least for starting plants.

The only use I have for peat is to spread a thin layer on my flower beds for extra organic matter and I always follow with some agricultural lime to counteract the acidity of peat.

Sorry my temps were way off...

Air temps for seedlings should be 50-65 degrees.

I push it and mine do pretty well at 65-70 but they would be happier a bit colder.

Keriann~

Thank you all for your advice I wouldn't have known being I'm fairly new at this. I'm definitely going to replant the healthy plants asap.

Something has changed with the product over the years. I am now finding the netting that holds the peat does not break apart and ends up girdling and killing my seedlings. I remember when the netting had a perforated side that allowed the plant roots to break the netting.. Now the perforated side is gone. I just dug up some easy to grow marigolds grown in peat potsthat are stunted. The netting was extremely tight and did not break away allowing the plant roots to seek out water and nutrients. I have cut and removed the netting in the hope to save my seedlings. I don't recommend this product at all now and won't use it again. No doubt the change in the product was to increase profits. I also noticed the jiffy pellet growing kit has an extremely cheap and flimsy plastic cover that barely works and makes the grower prone to dropping the tray. What a disappointment in a product.

I use 1/4 teaspoon builders sand on top of each pellet and after a few seedlings break the surface i remove the cover and add a fan to try to keep the top dryer than the bottom.

I use peat pellets to start some seeds, but not to grow on -- I transplant the seedlings into 2" or 4" plastic pots with peat-based potting mix when they have their first set of true leaves or soon thereafter.