diff --git a/include/econfig-spec.h b/include/econfig-spec.h
index 96e2ebdc..4c3fdd84 100644
--- a/include/econfig-spec.h
+++ b/include/econfig-spec.h
@@ -177,7 +177,7 @@ EMPCFBOTH("buil_tower_bt", buil_tower_bt, double, NSC_DOUBLE, 0,
 EMPCF_COMMENT("\n\n### Land Units")
 EMPCFBOTH("land_mob_scale", land_mob_scale, float, NSC_FLOAT, 0,
     "Land unit mobility accumulation (land_mob_scale * ETUs per update)")
-EMPCFBOTH("land_grow_scale", land_grow_scale, int, NSC_INT, 0,
+EMPCFBOTH("land_grow_scale", land_grow_scale, float, NSC_FLOAT, 0,
     "How fast efficiency grows for land units each update (* ETUs)")
 EMPCFBOTH("land_mob_max", land_mob_max, int, NSC_INT, 0,
     "Maximum mobility for land units")
@@ -189,7 +189,7 @@ EMPCFBOTH("morale_base", morale_base, int, NSC_INT, KM_INTERNAL,
 EMPCF_COMMENT("\n\n### Planes")
 EMPCFBOTH("plane_mob_scale", plane_mob_scale, float, NSC_FLOAT, 0,
     "Plane mobility accumulation (plane_mob_scale * ETUs per update)")
-EMPCFBOTH("plane_grow_scale", plane_grow_scale, int, NSC_INT, 0,
+EMPCFBOTH("plane_grow_scale", plane_grow_scale, float, NSC_FLOAT, 0,
     "How fast efficiency grows for planes each update (* ETUs)")
 EMPCFBOTH("plane_mob_max", plane_mob_max, int, NSC_INT, 0,
     "Maximum mobility for planes")
@@ -199,7 +199,7 @@ EMPCFBOTH("money_plane", money_plane, double, NSC_DOUBLE, 0,
 EMPCF_COMMENT("\n\n### Ships")
 EMPCFBOTH("ship_mob_scale", ship_mob_scale, float, NSC_FLOAT, 0,
     "Ship mobility accumulation (ship_mob_scale * ETUs per update)")
-EMPCFBOTH("ship_grow_scale", ship_grow_scale, int, NSC_INT, 0,
+EMPCFBOTH("ship_grow_scale", ship_grow_scale, float, NSC_FLOAT, 0,
     "How fast efficiency grows for ships each update (* ETUs)")
 EMPCFBOTH("ship_mob_max", ship_mob_max, int, NSC_INT, 0,
     "Maximum mobility for ships")
diff --git a/src/lib/commands/vers.c b/src/lib/commands/vers.c
index 364703d3..085b9d69 100644
--- a/src/lib/commands/vers.c
+++ b/src/lib/commands/vers.c
@@ -133,9 +133,9 @@ vers(void)
        (int)(plane_mob_scale * (float)etu_per_update),
        (int)(land_mob_scale * (float)etu_per_update));
     pr("Max eff gain per update\t\t--\t%d\t%d\t%d\n",
-       min(ship_grow_scale * etu_per_update, 100),
-       min(plane_grow_scale * etu_per_update, 100),
-       min(land_grow_scale * etu_per_update, 100));
+       min((int)(ship_grow_scale * (float)etu_per_update), 100),
+       min((int)(plane_grow_scale * (float)etu_per_update), 100),
+       min((int)(land_grow_scale * (float)etu_per_update), 100));
     pr("\n");
     pr("Ships on autonavigation may use %i cargo holds per ship.\n", TMAX);
     if (opt_TRADESHIPS) {
diff --git a/src/lib/global/constants.c b/src/lib/global/constants.c
index 1b27a8b6..2a60501f 100644
--- a/src/lib/global/constants.c
+++ b/src/lib/global/constants.c
@@ -107,9 +107,9 @@ int start_unit_type[START_UNITS] = { 0, 1 };	/* type of unit */
 /* opt_FUEL */
 int fuel_mult = 10;		/* 1 fuel = 10 mob */
 
-int land_grow_scale = 2;	/* how fast eff grows for land units (xETUS) */
-int ship_grow_scale = 3;	/* how fast eff grows for ships (xETUS) */
-int plane_grow_scale = 2;	/* how fast eff grows for planes (xETUS) */
+float land_grow_scale = 2.0;	/* how fast eff grows for land units (xETUS) */
+float ship_grow_scale = 3.0;	/* how fast eff grows for ships (xETUS) */
+float plane_grow_scale = 2.0;	/* how fast eff grows for planes (xETUS) */
 
 double fgrate = 0.0012;		/* food growth rate (dt * fert) */
 double fcrate = 0.0013;		/* food cultivate rate (dt * workforce) */
diff --git a/src/lib/update/land.c b/src/lib/update/land.c
index 09202718..3614918f 100644
--- a/src/lib/update/land.c
+++ b/src/lib/update/land.c
@@ -269,8 +269,8 @@ landrepair(struct lndstr *land, struct natstr *np,
     delta = roundavg((double)avail / w_p_eff);
     if (delta <= 0)
 	return 1;
-    if (delta > etus * land_grow_scale)
-	delta = etus * land_grow_scale;
+    if (delta > (int)((float)etus * land_grow_scale))
+	delta = (int)((float)etus * land_grow_scale);
 
     /* delta is the max amount we can grow */
 
diff --git a/src/lib/update/plane.c b/src/lib/update/plane.c
index 2be2f545..8e64ae2a 100644
--- a/src/lib/update/plane.c
+++ b/src/lib/update/plane.c
@@ -182,8 +182,8 @@ prod_plane(int etus, int natnum, int *bp, int buildem)
 	    delta = roundavg((double)avail / w_p_eff);
 	    if (delta <= 0)
 		continue;
-	    if (delta > etus * plane_grow_scale)
-		delta = etus * plane_grow_scale;
+	    if (delta > (int)((float)etus * plane_grow_scale))
+		delta = (int)((float)etus * plane_grow_scale);
 	    if (delta > left)
 		delta = left;
 
diff --git a/src/lib/update/ship.c b/src/lib/update/ship.c
index a597e1fe..5e8e5652 100644
--- a/src/lib/update/ship.c
+++ b/src/lib/update/ship.c
@@ -333,8 +333,8 @@ shiprepair(struct shpstr *ship, struct natstr *np,
     delta = roundavg((double)avail / w_p_eff);
     if (delta <= 0)
 	return 1;
-    if (delta > etus * ship_grow_scale)
-	delta = etus * ship_grow_scale;
+    if (delta > (int)((float)etus * ship_grow_scale))
+	delta = (int)((float)etus * ship_grow_scale);
     if (delta > left)
 	delta = left;