More information is required....what is your general location, are you attempting to grow your tumeric (Curcuma longa) in containers permanently? And will you be growing them inside or outside?

The browning of the edges is caused by something going on with the roots and potting medium, usually too much moisture.

Hi Rhizo, i am so sorry! I live in an apartment with a big window facing south east. I live in the netherlands 8b zone. The growing medium is for raised beds and pots specially formulated for growing food. It's 1/3 vermiculite ,1/3 compost and 1/3 turf. I water once a week till I see water coming out and if it's hot I'll poke my finger in the dirt to feel if it needs watering. I do not feed extra because the mix has nutrients in it. This is how it looks now. The new leave is stil bright but it Wil start to turn brown soon. I hope I can solve this soon. Thank you so much

I suspect that the potting mix is part of the problem. Vermiculite does very little if anything to promote the excellent porosity required by tumeric. If anything, it can create a sodden, boggy medium as the vermiculite particles begin to collapse. Vermiculite is very soft and weak structurally....you can test that by moistening some then rubbing gently between your fingers.

The product to use with the other ingredients (peat and compost) is vermiculite. The particles are extremely porous and resistant to collapse. I'd even consider using a greater proportion of perlite than your other components.

That may be leaf scorch something with several causes. A soil that is too wet, too much sun, too much fertilizer, but for some reason the leaves are not getting enough moisture to transpire.

Perhaps this article will be of some help.

http://extension.colostate.edu/topic-areas/yard-garden/leaf-scorch-2-911/

Are there drainage holes in the pot?