diff --git a/ApiCore-Frontend/src/app/(app)/colonies/[id]/feeding-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/colonies/[id]/feeding-edit-dialog.tsx
index 19821b6..5bd3301 100644
--- a/ApiCore-Frontend/src/app/(app)/colonies/[id]/feeding-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/colonies/[id]/feeding-edit-dialog.tsx
@@ -108,6 +108,7 @@ export function FeedingEditDialog({ feeding }: { feeding: Feeding }) {
               <Input
                 id="feeding-edit-amount"
                 type="number"
+                min={0}
                 value={amount}
                 onChange={(event) => setAmount(event.target.value)}
               />
diff --git a/ApiCore-Frontend/src/app/(app)/colonies/[id]/varroa-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/colonies/[id]/varroa-edit-dialog.tsx
index d430fad..503a340 100644
--- a/ApiCore-Frontend/src/app/(app)/colonies/[id]/varroa-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/colonies/[id]/varroa-edit-dialog.tsx
@@ -111,6 +111,7 @@ export function VarroaEditDialog({ measurement }: { measurement: VarroaMeasureme
             <Input
               id="varroa-edit-count"
               type="number"
+              min={0}
               value={miteCount}
               onChange={(event) => setMiteCount(event.target.value)}
             />
@@ -120,6 +121,7 @@ export function VarroaEditDialog({ measurement }: { measurement: VarroaMeasureme
             <Input
               id="varroa-edit-duration"
               type="number"
+              min={0}
               value={durationMinutes}
               onChange={(event) => setDurationMinutes(event.target.value)}
             />
@@ -130,6 +132,7 @@ export function VarroaEditDialog({ measurement }: { measurement: VarroaMeasureme
               id="varroa-edit-calculated"
               type="number"
               step="0.1"
+              min={0}
               value={calculatedValue}
               onChange={(event) => setCalculatedValue(event.target.value)}
             />
diff --git a/ApiCore-Frontend/src/app/(app)/extractions/[id]/extraction-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/extractions/[id]/extraction-edit-dialog.tsx
index b449004..0263e06 100644
--- a/ApiCore-Frontend/src/app/(app)/extractions/[id]/extraction-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/extractions/[id]/extraction-edit-dialog.tsx
@@ -78,6 +78,7 @@ export function ExtractionEditDialog({ extraction }: { extraction: Extraction })
               <Input
                 id="extraction-edit-amount"
                 type="number"
+                min={0}
                 value={amount}
                 onChange={(event) => setAmount(event.target.value)}
               />
@@ -97,6 +98,8 @@ export function ExtractionEditDialog({ extraction }: { extraction: Extraction })
               <Input
                 id="extraction-edit-water"
                 type="number"
+                min={0}
+                max={100}
                 value={waterContent}
                 onChange={(event) => setWaterContent(event.target.value)}
               />
diff --git a/ApiCore-Frontend/src/app/(app)/extractions/new/page.tsx b/ApiCore-Frontend/src/app/(app)/extractions/new/page.tsx
index f0e7966..ef9f2b7 100644
--- a/ApiCore-Frontend/src/app/(app)/extractions/new/page.tsx
+++ b/ApiCore-Frontend/src/app/(app)/extractions/new/page.tsx
@@ -123,6 +123,7 @@ export default function NewExtractionPage() {
                 id="extraction-amount"
                 type="number"
                 inputMode="decimal"
+                min={0}
                 className="h-11"
                 value={amount}
                 onChange={(event) => setAmount(event.target.value)}
@@ -143,6 +144,8 @@ export default function NewExtractionPage() {
                 id="extraction-water"
                 type="number"
                 inputMode="decimal"
+                min={0}
+                max={100}
                 className="h-11"
                 value={waterContent}
                 onChange={(event) => setWaterContent(event.target.value)}
diff --git a/ApiCore-Frontend/src/app/(app)/feedings/new/page.tsx b/ApiCore-Frontend/src/app/(app)/feedings/new/page.tsx
index db958bd..1a10c49 100644
--- a/ApiCore-Frontend/src/app/(app)/feedings/new/page.tsx
+++ b/ApiCore-Frontend/src/app/(app)/feedings/new/page.tsx
@@ -158,6 +158,7 @@ export default function NewFeedingPage() {
                   id="feeding-amount"
                   type="number"
                   inputMode="decimal"
+                  min={0}
                   required
                   className="h-11"
                   value={amount}
diff --git a/ApiCore-Frontend/src/app/(app)/harvests/[id]/harvest-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/harvests/[id]/harvest-edit-dialog.tsx
index 13b5e2f..15021d3 100644
--- a/ApiCore-Frontend/src/app/(app)/harvests/[id]/harvest-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/harvests/[id]/harvest-edit-dialog.tsx
@@ -88,6 +88,7 @@ export function HarvestEditDialog({ harvest }: { harvest: Harvest }) {
               <Input
                 id="harvest-edit-gross-weight"
                 type="number"
+                min={0}
                 value={grossWeight}
                 onChange={(event) => setGrossWeight(event.target.value)}
               />
@@ -97,6 +98,7 @@ export function HarvestEditDialog({ harvest }: { harvest: Harvest }) {
               <Input
                 id="harvest-edit-weight"
                 type="number"
+                min={0}
                 value={netWeight}
                 onChange={(event) => setNetWeight(event.target.value)}
               />
@@ -106,6 +108,7 @@ export function HarvestEditDialog({ harvest }: { harvest: Harvest }) {
               <Input
                 id="harvest-edit-supers"
                 type="number"
+                min={0}
                 value={honeySuperCount}
                 onChange={(event) => setHoneySuperCount(event.target.value)}
               />
diff --git a/ApiCore-Frontend/src/app/(app)/harvests/new/page.tsx b/ApiCore-Frontend/src/app/(app)/harvests/new/page.tsx
index 2cc402d..76aa604 100644
--- a/ApiCore-Frontend/src/app/(app)/harvests/new/page.tsx
+++ b/ApiCore-Frontend/src/app/(app)/harvests/new/page.tsx
@@ -202,6 +202,7 @@ export default function NewHarvestPage() {
                 id="harvest-super-count"
                 type="number"
                 inputMode="numeric"
+                min={0}
                 className="h-11"
                 value={honeySuperCount}
                 onChange={(event) => setHoneySuperCount(event.target.value)}
@@ -213,6 +214,7 @@ export default function NewHarvestPage() {
                 id="harvest-gross-weight"
                 type="number"
                 inputMode="decimal"
+                min={0}
                 className="h-11"
                 value={grossWeight}
                 onChange={(event) => setGrossWeight(event.target.value)}
@@ -224,6 +226,7 @@ export default function NewHarvestPage() {
                 id="harvest-net-weight"
                 type="number"
                 inputMode="decimal"
+                min={0}
                 className="h-11"
                 value={netWeight}
                 onChange={(event) => setNetWeight(event.target.value)}
diff --git a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/add-measurement-dialog.tsx b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/add-measurement-dialog.tsx
index d8fd8cc..7c86ad6 100644
--- a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/add-measurement-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/add-measurement-dialog.tsx
@@ -70,6 +70,8 @@ export function AddMeasurementDialog({ honeyBatchId }: { honeyBatchId: string })
               id="measurement-water"
               type="number"
               inputMode="decimal"
+              min={0}
+              max={100}
               required
               value={waterContent}
               onChange={(event) => setWaterContent(event.target.value)}
diff --git a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/extraction-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/extraction-edit-dialog.tsx
index eb99369..a53d1de 100644
--- a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/extraction-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/extraction-edit-dialog.tsx
@@ -77,6 +77,7 @@ function ExtractionEditForm({
         <Input
           id="extraction-edit-amount"
           type="number"
+          min={0}
           value={amount}
           onChange={(event) => setAmount(event.target.value)}
         />
@@ -96,6 +97,8 @@ function ExtractionEditForm({
             id="extraction-edit-water"
             type="number"
             step="0.1"
+            min={0}
+            max={100}
             value={waterContent}
             onChange={(event) => setWaterContent(event.target.value)}
           />
diff --git a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/honey-batch-edit-dialog.tsx b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/honey-batch-edit-dialog.tsx
index 7a72095..a019839 100644
--- a/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/honey-batch-edit-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/honey-batches/[id]/honey-batch-edit-dialog.tsx
@@ -72,6 +72,7 @@ export function HoneyBatchEditDialog({ honeyBatch }: { honeyBatch: HoneyBatch })
               id="batch-edit-amount"
               type="number"
               inputMode="decimal"
+              min={0}
               value={amount}
               onChange={(event) => setAmount(event.target.value)}
             />
@@ -82,6 +83,8 @@ export function HoneyBatchEditDialog({ honeyBatch }: { honeyBatch: HoneyBatch })
               id="batch-edit-water"
               type="number"
               step="0.1"
+              min={0}
+              max={100}
               value={waterContent}
               onChange={(event) => setWaterContent(event.target.value)}
             />
diff --git a/ApiCore-Frontend/src/app/(app)/storage/create-stock-item-dialog.tsx b/ApiCore-Frontend/src/app/(app)/storage/create-stock-item-dialog.tsx
index b3aae4d..5d6e1c8 100644
--- a/ApiCore-Frontend/src/app/(app)/storage/create-stock-item-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/storage/create-stock-item-dialog.tsx
@@ -109,6 +109,7 @@ export function CreateStockItemDialog() {
               id="item-quantity"
               type="number"
               inputMode="decimal"
+              min={0}
               value={quantity}
               onChange={(event) => setQuantity(event.target.value)}
             />
diff --git a/ApiCore-Frontend/src/app/(app)/storage/edit-stock-item-dialog.tsx b/ApiCore-Frontend/src/app/(app)/storage/edit-stock-item-dialog.tsx
index b11a8cb..7515a87 100644
--- a/ApiCore-Frontend/src/app/(app)/storage/edit-stock-item-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/storage/edit-stock-item-dialog.tsx
@@ -112,6 +112,7 @@ export function EditStockItemDialog({ item }: { item: StockItem }) {
               id="item-edit-min-threshold"
               type="number"
               inputMode="decimal"
+              min={0}
               value={minThreshold}
               onChange={(event) => setMinThreshold(event.target.value)}
             />
diff --git a/ApiCore-Frontend/src/app/(app)/storage/record-movement-dialog.tsx b/ApiCore-Frontend/src/app/(app)/storage/record-movement-dialog.tsx
index 03f704d..9e4783d 100644
--- a/ApiCore-Frontend/src/app/(app)/storage/record-movement-dialog.tsx
+++ b/ApiCore-Frontend/src/app/(app)/storage/record-movement-dialog.tsx
@@ -87,10 +87,15 @@ export function RecordMovementDialog({ stockItemId }: { stockItemId: string }) {
               id="movement-quantity"
               type="number"
               inputMode="decimal"
+              min={type === "ADJUSTMENT" ? undefined : 0}
               required
               value={quantity}
               onChange={(event) => setQuantity(event.target.value)}
             />
+            <p className="text-xs text-muted-foreground">
+              Bei Eingang/Ausgang/Umlagerung immer positiv angeben - die Richtung ergibt sich aus
+              der Art. Nur bei Korrektur ist ein negativer Wert möglich.
+            </p>
           </div>
           {error ? (
             <p role="alert" className="text-sm text-destructive">
diff --git a/ApiCore-Frontend/src/app/(app)/varroa/new/page.tsx b/ApiCore-Frontend/src/app/(app)/varroa/new/page.tsx
index 64f6f71..d124442 100644
--- a/ApiCore-Frontend/src/app/(app)/varroa/new/page.tsx
+++ b/ApiCore-Frontend/src/app/(app)/varroa/new/page.tsx
@@ -149,6 +149,7 @@ export default function NewVarroaMeasurementPage() {
                 id="varroa-mite-count"
                 type="number"
                 inputMode="numeric"
+                min={0}
                 className="h-11"
                 value={miteCount}
                 onChange={(event) => setMiteCount(event.target.value)}
@@ -160,6 +161,7 @@ export default function NewVarroaMeasurementPage() {
                 id="varroa-duration"
                 type="number"
                 inputMode="numeric"
+                min={0}
                 className="h-11"
                 value={durationMinutes}
                 onChange={(event) => setDurationMinutes(event.target.value)}