If you fill out
the troubleshooting form you will get more help and more definitive answers.
It may be a deficiency but it does
not look like a Nitrogen deficiency to me. N defs start with yellowing of the lower leaves and works its way up usually with a noted paleness as it does. It doesn't just affect the tips and edges or make them crispy and up-curled quite like that. It is more likely nute burn, which does start at the leaf tips and edges. It is hard to say with such limited information however.
Here is a great link on deficiencies and other plant troubles.