diff --git a/frontend/src/components/Mowing/MowingExecutionModal.js b/frontend/src/components/Mowing/MowingExecutionModal.js
index 3553de1..1e66cb0 100644
--- a/frontend/src/components/Mowing/MowingExecutionModal.js
+++ b/frontend/src/components/Mowing/MowingExecutionModal.js
@@ -112,6 +112,10 @@ const MowingExecutionModal = ({ plan, onClose, onComplete }) => {
         }
       } catch {}
 
+      // Ensure positive, non-zero totals for backend validation
+      const totalMeters = Math.max(Math.round(totalDistance*100)/100, 0.01);
+      const avgMph = Math.max(averageSpeed, 0.1);
+
       const payload = {
         propertyId: plan.property_id,
         lawnSectionIds: sections.map(s=>s.id),
@@ -119,12 +123,15 @@ const MowingExecutionModal = ({ plan, onClose, onComplete }) => {
         cutHeightInches: plan.cut_height_inches,
         direction: plan.direction,
         gpsTrack: { points: gpsTrack, totalDistance: Math.round(totalDistance*100)/100, duration: durationSeconds, averageSpeed: Math.round(averageSpeed*100)/100 },
-        averageSpeed: Math.max(averageSpeed, 0.1),
+        averageSpeed: avgMph,
         durationSeconds,
-        totalDistanceMeters: Math.round(totalDistance*100)/100,
-        areaCoveredSqft,
+        totalDistanceMeters: totalMeters,
         notes: ''
       };
+      // Only include areaCoveredSqft if we computed a number
+      if (typeof areaCoveredSqft === 'number' && !Number.isNaN(areaCoveredSqft) && areaCoveredSqft > 0) {
+        payload.areaCoveredSqft = areaCoveredSqft;
+      }
       await mowingAPI.createLog(payload);
       await mowingAPI.updatePlanStatus(plan.id, 'completed');
       toast.success('Mowing session saved');