diff --git a/greenhouse.ino b/greenhouse.ino
index e5bcaa4..affd9d0 100644
--- a/greenhouse.ino
+++ b/greenhouse.ino
@@ -10,6 +10,7 @@
 int sample_idx = 0;
 int voltage_reads[SAMPLES];
 int moisture_reads[SAMPLES];
+bool radio_initialized = false;
 
 #define NODEBUG
  
@@ -29,6 +30,7 @@
  * voltage: 161 fully charged, 1.37V each cell
  * voltage: 162 fully charged + bit of sun.
  * voltage: 155 after running quite a bit
+ * voltage: 130 minimum below which radio no longer works
  * moisture: 880 dry / 600 wet
  */
 
@@ -69,6 +71,13 @@
   HOME_ID, STATION_ID, 0, 0
 };
 
+bool setupLoRa() {
+  LoRa.setPins(10, 9, 2);
+  LoRa.enableCrc();
+  LoRa.onReceive(onReceive);
+  return LoRa.begin(868E6);
+}
+
 void setup() {
 #ifdef DEBUG
   Serial.begin(9600);
@@ -86,17 +95,21 @@
 //  EEPROM.put(0, state);
 
   analogReference(DEFAULT);
-  LoRa.setPins(10, 9, 2);
-  LoRa.enableCrc();
-  LoRa.begin(868E6);
-  LoRa.onReceive(onReceive);
   pumpOff();
+  int voltage = 0;
   for (int i=0; i<SAMPLES; i++) {
     voltage_reads[i] = analogRead(A0);
+    voltage = voltage + voltage_reads[i];
     moisture_reads[i] = analogRead(A1);
     delay(50);
   }
-  LoRa.receive();
+  voltage = voltage / SAMPLES;
+  if (voltage > 130) {
+    radio_initialized = setupLoRa();
+    if (radio_initialized) {
+      LoRa.receive();
+    }
+  }
 }
 
 void pumpOn(int speed) {
@@ -131,6 +144,10 @@
     moisture = moisture + moisture_reads[i];
   }
   state.voltage = voltage / SAMPLES;
+  if (state.voltage <= 135) {
+    LoRa.end();
+    radio_initialized = false;
+  }
   state.moisture = moisture / SAMPLES;
   DPRINT("voltage = ");
   DPRINTLN(state.voltage);
@@ -140,6 +157,8 @@
   DPRINTLN(state.state);
   DPRINT("intervals = ");
   DPRINTLN(state.intervals);
+  DPRINT("radio = ");
+  DPRINTLN(radio_initialized);
   DFLUSH;
   switch(state.state) {
     case WAIT_FOR_DELAY_OR_DRY:
@@ -190,11 +209,15 @@
 }
 
 void sendState() {
-  LoRa.beginPacket();
-  LoRa.write((byte *)&(my_header), sizeof(Header));
-  LoRa.write((byte *)&(state), sizeof(State));
-  LoRa.endPacket();
-  LoRa.receive();
+  if (radio_initialized) {
+    LoRa.beginPacket();
+    LoRa.write((byte *)&(my_header), sizeof(Header));
+    LoRa.write((byte *)&(state), sizeof(State));
+    LoRa.endPacket();
+    LoRa.receive();
+  } else {
+    radio_initialized = setupLoRa();
+  }
 }
 
 void onReceive(int packetSize) {