Those are sometimes referred to as helmet heads. One thing that helps is planting the seeds a little deeper so the seed coats are more likely to be scraped off as the seedling fights its way to the surface. You can keep putting drops of water or spit on the seed coat to soften it up. If the seedlings cotyledons don't come out by themselves after a day or two often you can pull the softened seed coat off by hand, being very gentle. Sometimes though you will accidentally rip the top off the seedling and kill it.

I won't tell anybody else in the house I'm going to spit on my helmet heads. They'll think I've lost it !

Thanks for the tip, and also the advice to plant deeper. =:)

I have to ask though......why spit? Just because it's easy?

Because it's easy, lubricates better than water and won't damage the plants like soap or oil.
Don't plant too deeply next time. 1/8" is deep enough if you slightly pack the soil, 1/4" max IMO. I plant 1/8" and had one helmet head out of 66 plants but it didn't need any help.

I had this problem with one of my heirlooms, can't remember which one, and the attached seed coats prevented any leaves from emerging. I had to start a second batch of seeds, and I clipped off a tiny sliver of the seed coat with very sharp scissors before planting. That solved the problem and the seeds developed normally. Tom

Spit is the common way of removing them - enzymes in the saliva. But also keep in mind that removing them isn't "crucial" as in life threatening. If you have just a few plants fine but with hundreds of plants you'd quickly run of out spit. :) Most do fine if just left alone.

Dave

Saliva enzymes....hmmm, I hadn't considered that. Makes sense, though. I thought it was just because it stuck onto the seed coat better and stayed wet longer than water.

nutsaboutflowers: I don't let people at my house see me putting spit on the plants either :) There are a few other gardening practices I hide from them, too.

I use water and a very thin wire. I drip water on to the openig of the seed coat and then slide the wire in and push it off.

The water and wire sound like an interesting idea.

I'll try all methods.

Thanks!

MIST OFTEN. ALSO CAN USE A TWIZZER INSTEAD OF BARE HAND.

I second the mist and tweezer method. Wire sounds interesting. In my experience, the ones that get deformed seed leaves generally don't do quite as well. Part of that might be that the plant is less vigorous to begin with. Sow redundantly if you can.

(With tiny seedlings like petunias, helmet head is often fatal and I haven't found a solution. It's especially frustrating given the cost of the seed and the amount of seed per packet.)

This is a cultural problem, not the kind of seeds you're growing. "helmet head" is caused by lowering the humidity too quickly after the root part of the plant emerges from the seeds. Keep those germination domes on for a few days after radicle emergence (root part). If the humidity stays higher until the seed coat splits, there will be no problems.