I think more than 50% of my seeds come up like this, and man I get real tired of doing the surgery.
How do you prevent this crap?
I’ve heard scarification of the seed with sand paper will make it less likely, but is that true?
If you do get a helmet head, how do you deal with it?
I spray water on the seed shell every chance I get for about 24 hours, and then hold the plant with a tweezer while I poke the shell off with a needle.
Seems to me the basic problem is the hinge between the two half shells. Anything that weakens that will help.
Maybe a little filing back there before soaking? 
or by other means…
Cheers
G
Plant seed a little deeper. ???
Yeah that ^^
And pointy side up, let geotropism do the work
Sometimes I just pull them by hand, like a sock.
Some stock will do it more than others.
If I were you I’d stick with the tweezers and a good soak.
It sucks to rip the cotylydons a bit but not the end of the world.
All the best.
Sow deeper, pack harder, don’t let the wet spot dry out.
Spritz the helmets and they’ll come loose.
leave them, when the cotyledons open up, itll force the casing to fall off.
natures been doing that since the dawn of time.
Planting them just a little bit deeper helped a ton when I started seeing to many helmets.
If they sit like that for more than a day or two, it seems like they have a hard time getting going. If its bought seeds, I mist them and give it a day, then help em out if needed. If its my seeds, where I have a bunch, I just let the strong survive.
I soak the seeds for 24-48 hours before sowing, most will usually crack and have tails by then, and I think the soak weakens the helmet making it easier for them to fall off naturally, but I still have to pull 1 or 2 off occasionally. +1 for planting them deeper, that’s something I need to be better with.
…reminds me of a story from my dad…
he decided to let 4 yr-old me & 2yr-old 'sis help plant some ornamental seeds out front & instructed us to make a hole with our finger & sprinkle a few in.
needless to say I began excavating a large hole while my sister flung the seeds in the street.
Spray mist them a couple of times a day. It’s like a chicken breaking out of it’s egg – If the plant cannot shed the moist husk it probably does not have the energy to suffer through life.
I really must not be planting deep enough because this one fully popped out of the coco and was laying across it sideways.
I performed helmet surgery number 20,999 and I created a small hole and tried to place the seedling in without damaging the tap root.
Cotyledons are yellow for some reason and so are the first set of true leaves
Going to see what happens next 24 hours but not much hope for this young Skywalker
Dying over here picturing this 
Had one crawl out of the hole in the rock wool (looked deep to me) crawl across the tray, a couple runs back.
I agree with letting nature do it’s thing but you can scuff them up by gently using some very light sandpaper or soak them in a diluted hydrogen peroxide mix over night.
I think it’s 10:1 water to peroxide
You can’t…it’s protein that needs to dissolve. The more it splits can carefully w a nail or tweezer help it lose. I lightly try to loosen the split and see if I can pull it off gently. Sometimes it’s stuck, so do little bits at a time to keep helping it along, until I can finally remove the husk off
Another good way to get it off is increasing the humidity by placing a clear solo cup over it make sure there are a few holes in the cup. You can also put a baggie over the bottom of the cup of needed just keep an eye out. In a few hours under the humidity, the shell will easily slide off.
I am trying out little wet paper towel squares over freshly sowed seeds, so i can water without displacing the soil until they come up. 
I used to mist or use my finger or syringe to leave a single drop on it’s head
I have a little bottle, maybe 1 by 2 inches, that I lined with a piece of sandpaper. Drop your seeds in there and give it a shake. I have fairly rough sandpaper in mine and shake it for maybe 30s or so. You should see the edges of the seeds being slightly scuffed. When or if the seedlings helmet, they crack open much easier. I can remove most of them with my fingers by just trying to gently split the seed open.
You might want to try some bagseed to check how long you need to shake for. Then as everyone has suggested plant them a little deeper.
