diff --git a/strbuf.c b/strbuf.c
index bc3a0802e..73e040059 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -30,8 +30,10 @@ void strbuf_init(struct strbuf *sb, size_t hint)
 {
 	sb->alloc = sb->len = 0;
 	sb->buf = strbuf_slopbuf;
-	if (hint)
+	if (hint) {
 		strbuf_grow(sb, hint);
+		sb->buf[0] = '\0';
+	}
 }
 
 void strbuf_release(struct strbuf *sb)