diff --git a/dlgr/griduniverse/experiment.py b/dlgr/griduniverse/experiment.py
index 476bd5ca..6d3d0aba 100644
--- a/dlgr/griduniverse/experiment.py
+++ b/dlgr/griduniverse/experiment.py
@@ -683,6 +683,30 @@ def items_changed(self, last_items):
                 return True
         return False
 
+    def trigger_transitions(self, time=time.time):
+        now = time()
+        to_change = []
+        for position, item in self.item_locations.items():
+            item_type = self.item_config.get(item.item_id)
+            if not item_type:
+                continue
+            if "auto_transition_time" in item_type:
+                if now - item.creation_timestamp >= item_type["auto_transition_time"]:
+                    target = item_type.get("auto_transition_target")
+                    new_target_item = target and Item(
+                        id=item.id,
+                        position=position,
+                        item_config=self.item_config[target],
+                    )
+                    to_change.append((position, new_target_item))
+        if to_change:
+            self.items_updated = True
+        for position, new_target_item in to_change:
+            if new_target_item is None:
+                del self.item_locations[position]
+            else:
+                self.item_locations[position] = new_target_item
+
     def replenish_items(self):
         items_by_type = collections.defaultdict(list)
         for item in self.item_locations.values():
@@ -1748,6 +1772,8 @@ def game_loop(self):
             if (now - previous_second_timestamp) > 1.000:
                 # Grow or shrink the item stores.
                 self.grid.replenish_items()
+                # Trigger automatic transitions.
+                self.grid.trigger_transitions()
 
                 abundances = {}
                 for player in self.grid.players.values():
diff --git a/dlgr/griduniverse/game_config.yml b/dlgr/griduniverse/game_config.yml
index e3e4fc7c..ada550fe 100644
--- a/dlgr/griduniverse/game_config.yml
+++ b/dlgr/griduniverse/game_config.yml
@@ -275,6 +275,52 @@ items:
     portable: false
     crossable: true
 
+  - name: Sunflower sprout
+    item_id: sunflower_sprout
+    n_uses: 1
+    sprite: "emoji:🌱"
+    interactive: true
+    spawn_rate: 0.9
+    item_count: 90
+    portable: false
+    crossable: true
+    auto_transition_time: 5
+    auto_transition_target: sunflower_bud
+
+  - name: Sunflower bud
+    item_id: sunflower_bud
+    n_uses: 1
+    sprite: "emoji:🌼"
+    interactive: true
+    spawn_rate: 0
+    item_count: 0
+    portable: false
+    crossable: true
+    auto_transition_time: 5
+    auto_transition_target: sunflower_bloom
+
+  - name: Sunflower bloom
+    item_id: sunflower_bloom
+    n_uses: 1
+    sprite: "emoji:🌻"
+    interactive: true
+    spawn_rate: 0
+    item_count: 0
+    portable: false
+    crossable: true
+    auto_transition_time: 5
+    auto_transition_target: sunflower_dried
+
+  - name: Sunflower dried
+    item_id: sunflower_dried
+    n_uses: 1
+    sprite: "emoji:🥀"
+    interactive: true
+    spawn_rate: 0
+    item_count: 0
+    portable: false
+    crossable: true
+
 transitions:
   - actor_start: stone
     actor_end: sharp_stone
diff --git a/test/test_automatic_transitions.py b/test/test_automatic_transitions.py
new file mode 100644
index 00000000..23f701b3
--- /dev/null
+++ b/test/test_automatic_transitions.py
@@ -0,0 +1,57 @@
+import time
+
+import pytest
+
+
+class TestAutoTransition(object):
+    messages = []
+
+    def test_automatic_transition(self, exp):
+        from dlgr.griduniverse.experiment import Item
+
+        item = Item(
+            {
+                "id": 1,
+                "item_id": "sunflower_sprout",
+                "name": "Sunflower Sprout",
+                "n_uses": 1,
+            }
+        )
+        exp.grid.item_locations[(2, 2)] = item
+
+        exp.grid.trigger_transitions(time=lambda: time.time() + 5)
+        assert exp.grid.item_locations[(2, 2)].item_id == "sunflower_bud"
+
+    def test_null_target(self, exp):
+        from dlgr.griduniverse.experiment import Item
+
+        item = Item(
+            {
+                "id": 1,
+                "item_id": "sunflower_dried",
+                "name": "Sunflower Dried",
+                "n_uses": 1,
+            }
+        )
+        exp.grid.item_locations[(2, 2)] = item
+
+        exp.item_config["sunflower_sprout"]["auto_transition_target"] = None
+        exp.grid.trigger_transitions(time=lambda: time.time() + 5)
+        assert (2, 2) not in exp.grid.item_locations
+
+
+@pytest.fixture(autouse=True)
+def add_item_config(exp):
+    """Make sure item configs needed for these tests are set"""
+    exp.grid.item_config["sunflower_dried"] = {
+        "name": "Sunflower dried",
+        "item_id": "sunflower_dried",
+        "n_uses": 1,
+        "auto_transition_time": 5,
+    }
+    exp.grid.item_config["sunflower_sprout"] = {
+        "auto_transition_target": "sunflower_bud",
+        "auto_transition_time": 5,
+        "n_uses": 1,
+        "name": "Sunflower sprout",
+    }