diff --git a/src/USER-PLUMED/fix_plumed.cpp b/src/USER-PLUMED/fix_plumed.cpp
index 4bf5acedc5b5046b0f8751e3e3d2aa969a59fd32..635d08c573b00939b5247fe4d92d243b390e7d2e 100644
--- a/src/USER-PLUMED/fix_plumed.cpp
+++ b/src/USER-PLUMED/fix_plumed.cpp
@@ -213,7 +213,7 @@ FixPlumed::FixPlumed(LAMMPS *lmp, int narg, char **arg) :
 
   // Define compute to calculate potential energy
 
-  id_pe = new char[7];
+  id_pe = new char[8];
   strcpy(id_pe,"plmd_pe");
   char **newarg = new char*[3];
   newarg[0] = id_pe;
@@ -226,7 +226,7 @@ FixPlumed::FixPlumed(LAMMPS *lmp, int narg, char **arg) :
 
   // Define compute to calculate pressure tensor
 
-  id_press = new char[9];
+  id_press = new char[11];
   strcpy(id_press,"plmd_press");
   newarg = new char*[5];
   newarg[0] = id_press;