diff --git a/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx b/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
index 69dfdf3..3366777 100644
--- a/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
+++ b/frontend/src/app/fertilizer/_components/FertilizerEditPage.tsx
@@ -369,7 +369,10 @@ export default function FertilizerEditPage({ planId }: { planId?: number }) {
   const getPlanAvailableStock = (fertilizer: Fertilizer) => {
     const stock = getStockInfo(fertilizer);
     if (!stock) return null;
-    return getNumericValue(stock.available_stock);
+    const serverAvailable = getNumericValue(stock.available_stock);
+    const initialReserve = initialPlanTotals[fertilizer.id] ?? 0;
+    const currentPlanTotal = colTotal(fertilizer.id);
+    return serverAvailable + initialReserve - currentPlanTotal;
   };
   const getPlanShortage = (fertilizer: Fertilizer) => {
     const available = getPlanAvailableStock(fertilizer);