diff --git a/training_config/bidaf.jsonnet b/training_config/bidaf.jsonnet
index 48b0f8f0c35..33f8bcc3c08 100644
--- a/training_config/bidaf.jsonnet
+++ b/training_config/bidaf.jsonnet
@@ -15,7 +15,8 @@
           "byte_encoding": "utf-8",
           "start_tokens": [259],
           "end_tokens": [260]
-        }
+        },
+        "min_padding_length": 5
       }
     }
   },
diff --git a/training_config/bidaf_elmo.jsonnet b/training_config/bidaf_elmo.jsonnet
index bad16be964e..c16cd68edb6 100644
--- a/training_config/bidaf_elmo.jsonnet
+++ b/training_config/bidaf_elmo.jsonnet
@@ -18,7 +18,8 @@
           "byte_encoding": "utf-8",
           "start_tokens": [259],
           "end_tokens": [260]
-        }
+        },
+        "min_padding_length": 5
       }
     }
   },
diff --git a/training_config/coref.jsonnet b/training_config/coref.jsonnet
index 2b27810c2f0..a5fb819484d 100644
--- a/training_config/coref.jsonnet
+++ b/training_config/coref.jsonnet
@@ -9,7 +9,8 @@
         "lowercase_tokens": false
       },
       "token_characters": {
-        "type": "characters"
+        "type": "characters",
+        "min_padding_length": 5
       }
     },
     "max_span_width": 10
diff --git a/training_config/dialog_qa.jsonnet b/training_config/dialog_qa.jsonnet
index 8639a5a0887..532030f5d0e 100644
--- a/training_config/dialog_qa.jsonnet
+++ b/training_config/dialog_qa.jsonnet
@@ -17,7 +17,8 @@
                     "start_tokens": [
                         259
                     ]
-                }
+                },
+                "min_padding_length": 5
             }
         }
     },
diff --git a/training_config/ner.jsonnet b/training_config/ner.jsonnet
index 4af5c3d3d17..2a1785eb05f 100644
--- a/training_config/ner.jsonnet
+++ b/training_config/ner.jsonnet
@@ -11,8 +11,9 @@
         "lowercase_tokens": true
       },
       "token_characters": {
-        "type": "characters"
-      },
+        "type": "characters",
+        "min_padding_length": 3
+      }
     }
   },
   "train_data_path": std.extVar("NER_TRAIN_DATA_PATH"),
diff --git a/training_config/ner_elmo.jsonnet b/training_config/ner_elmo.jsonnet
index 7fdd76beb87..b9668b7491b 100644
--- a/training_config/ner_elmo.jsonnet
+++ b/training_config/ner_elmo.jsonnet
@@ -19,7 +19,8 @@
         "lowercase_tokens": true
       },
       "token_characters": {
-        "type": "characters"
+        "type": "characters",
+        "min_padding_length": 3
       },
       "elmo": {
         "type": "elmo_characters"