diff --git a/backend/app/config.py b/backend/app/config.py
index bdde0ca..3ecbcfb 100644
--- a/backend/app/config.py
+++ b/backend/app/config.py
@@ -9,7 +9,7 @@
 REPO_ROOT = BACKEND_ROOT.parent
 
 
-def _default_data_dir() -> Path:
+def get_data_dir() -> Path:
     configured_data_dir = os.getenv("DATA_DIR")
     if configured_data_dir:
         candidate = Path(configured_data_dir)
@@ -26,7 +26,8 @@ def _default_data_dir() -> Path:
     return Path("/tmp/gitplant-data")
 
 
-def _ensure_writable_data_dir(path: Path) -> Path:
+def ensure_data_dir() -> Path:
+    path = get_data_dir()
     try:
         path.mkdir(parents=True, exist_ok=True)
         return path
@@ -37,7 +38,7 @@ def _ensure_writable_data_dir(path: Path) -> Path:
 
 
 # Vercel serverless functions run on a read-only filesystem except for /tmp.
-DEFAULT_DATA_DIR = _ensure_writable_data_dir(_default_data_dir())
+DEFAULT_DATA_DIR = get_data_dir()
 DEFAULT_DB_PATH = DEFAULT_DATA_DIR / "edms.db"
 DEFAULT_DATABASE_URL = f"sqlite:///{quote(str(DEFAULT_DB_PATH), safe='/')}"
 DEFAULT_STORAGE_DIR = DEFAULT_DATA_DIR / "documents"
@@ -103,17 +104,32 @@ def sanitize_database_url(database_url: str) -> str:
     return parsed._replace(netloc=netloc).geturl()
 
 
-def _ensure_path(path: str) -> Path:
+def _resolve_path(path: str) -> Path:
     configured = Path(path)
     if not configured.is_absolute():
         configured = (BACKEND_ROOT / configured).resolve()
+    return configured
+
+
+def _ensure_path(path: str) -> Path:
+    configured = _resolve_path(path)
     configured.mkdir(parents=True, exist_ok=True)
     return configured
 
 
-def get_document_storage_path() -> Path:
-    return _ensure_path(settings.document_storage_dir)
+def get_document_storage_path(*, ensure_exists: bool = True) -> Path:
+    if settings.document_storage_dir == str(DEFAULT_STORAGE_DIR):
+        base_path = ensure_data_dir() / "documents" if ensure_exists else get_data_dir() / "documents"
+        if ensure_exists:
+            base_path.mkdir(parents=True, exist_ok=True)
+        return base_path
+    return _ensure_path(settings.document_storage_dir) if ensure_exists else _resolve_path(settings.document_storage_dir)
 
 
-def get_plant_storage_path() -> Path:
-    return _ensure_path(settings.plant_storage_dir)
+def get_plant_storage_path(*, ensure_exists: bool = True) -> Path:
+    if settings.plant_storage_dir == str(DEFAULT_PLANT_STORAGE_DIR):
+        base_path = ensure_data_dir() / "plant" if ensure_exists else get_data_dir() / "plant"
+        if ensure_exists:
+            base_path.mkdir(parents=True, exist_ok=True)
+        return base_path
+    return _ensure_path(settings.plant_storage_dir) if ensure_exists else _resolve_path(settings.plant_storage_dir)
diff --git a/backend/app/db.py b/backend/app/db.py
index a3ff2f6..583c7d9 100644
--- a/backend/app/db.py
+++ b/backend/app/db.py
@@ -3,13 +3,13 @@
 from app.config import resolve_sqlite_path, settings
 
 sqlite_path = resolve_sqlite_path(settings.database_url)
-if sqlite_path is not None:
-    sqlite_path.parent.mkdir(parents=True, exist_ok=True)
 
 engine = create_engine(settings.database_url, echo=False)
 
 
 def init_db() -> None:
+    if sqlite_path is not None:
+        sqlite_path.parent.mkdir(parents=True, exist_ok=True)
     SQLModel.metadata.create_all(engine)
 
 
diff --git a/backend/app/routers/documents.py b/backend/app/routers/documents.py
index 200fa9a..7b7f176 100644
--- a/backend/app/routers/documents.py
+++ b/backend/app/routers/documents.py
@@ -54,7 +54,7 @@
 
 router = APIRouter(prefix="/documents", tags=["documents"])
 
-DOCUMENT_STORAGE_DIR = get_document_storage_path()
+DOCUMENT_STORAGE_DIR = get_document_storage_path(ensure_exists=False)
 
 
 def record_audit_event(
@@ -91,7 +91,7 @@ def _clear_documents_and_storage(session: Session) -> None:
     session.exec(delete(Document))
     session.commit()
 
-    for path in DOCUMENT_STORAGE_DIR.glob("*.pdf"):
+    for path in get_document_storage_path(ensure_exists=False).glob("*.pdf"):
         path.unlink(missing_ok=True)
 
 
@@ -352,7 +352,7 @@ def create_documents_from_pdf_upload(
         session.refresh(document)
 
         file.file.seek(0)
-        destination = DOCUMENT_STORAGE_DIR / f"{document.id}.pdf"
+        destination = get_document_storage_path() / f"{document.id}.pdf"
         with destination.open("wb") as output_stream:
             output_stream.write(file.file.read())
         document.file_path = str(destination)
@@ -395,7 +395,7 @@ def upload_plant_revision(
         raise HTTPException(status_code=400, detail="Only PDF files are supported")
 
     next_revision = _next_revision(document.current_revision)
-    destination = DOCUMENT_STORAGE_DIR / f"{document_id}.pdf"
+    destination = get_document_storage_path() / f"{document_id}.pdf"
     file.file.seek(0)
     destination.write_bytes(file.file.read())
 
diff --git a/backend/app/routers/projects.py b/backend/app/routers/projects.py
index 75ec9e8..258b875 100644
--- a/backend/app/routers/projects.py
+++ b/backend/app/routers/projects.py
@@ -30,7 +30,10 @@
 
 ACTIVE_WORKING_STATUSES = {"WORKING", "READY"}
 WORKING_STORAGE_DIR = (BACKEND_ROOT / "storage" / "projects").resolve()
-WORKING_STORAGE_DIR.mkdir(parents=True, exist_ok=True)
+
+
+def ensure_working_storage_dir() -> None:
+    WORKING_STORAGE_DIR.mkdir(parents=True, exist_ok=True)
 
 
 def _to_working_response(
@@ -290,6 +293,7 @@ def upload_working_revision_file(
     if not filename.endswith(".pdf"):
         raise HTTPException(status_code=400, detail="Only PDF files are supported")
 
+    ensure_working_storage_dir()
     destination = WORKING_STORAGE_DIR / f"{project.id}-{working.id}.pdf"
     file.file.seek(0)
     destination.write_bytes(file.file.read())