This is an irregular verb. It follows the conjugation pattern of the verb ficar.
Present:
A Ana seca o cabelo depois do banho.
Ana dries her hair after the shower.
Preterite:
O Miguel secou a louça rapidamente.
O Miguel secou a loiça rapidamente.
Miguel dried the dishes quickly.
Conditional:
A Clara secaria as roupas do lado de fora.
A Clara secaria a roupa lá fora.
Clara would dry the clothes outside.