The new central growth looks fine. So if the leaves with brown edges are from last year, they're old and should be removed. If they're from this year, likely temporary low root function while the leaves were growing.

Jean is right - definitely root related. I have seen similar from the soil being too wet OR too dry and also from a bit too much fertilizer.
hortster

Someone else mentioned to me that tap water with chlorine can cause this. If you look at the edges they are not only brown but a blueish/purple. That could be over fertilization or most likely chlorine/chloromine in the water. I dont know though, that is only what I have heard/read.

Mine have begun to do the same thing but in only one pot that I fertilized. The other non fertilized pot is fine. I do know that I have some chlorine in my water, not much though but enough to kill most of my seedlings.

why is it potted??

is frost/freeze a possibility???

did the pots ever dry out too much???

whats your potting media ... looks like pure peat almost??

is it outdoors.. is there sufficient light?:?

ken

that letting water stand for a day or two.. will allow the city water additives .. like chlorine and fluoride.. to dissipate ...

i used to fill gallon milk jugs with water ... and let them stand for a few days.. cycling thru them ...

any reality to that theory???

ken

"...any reality to that theory??? "

Only for chlorine. Fluoride stays and I'm not sure if chloramine ever dissipates unless the water is boiled.

tj

I've got the same problem with my strawberries. Worrying me a bit. I put them in a mixture of organic potting mix and peat moss. I read yesterday though, that peat moss can make the soil too acidic. That might be something for us both to check into.

Potassium deficiency, perhaps.