diff --git a/src/main/java/no/bioforsk/vips/model/naerstadmodel/NaerstadModel.java b/src/main/java/no/bioforsk/vips/model/naerstadmodel/NaerstadModel.java
index 4d5275f4c199fb896fb8efd81526d4c7b8e1d40d..e610b78b4973e20897ed5470c7dd20cfdbe744dd 100644
--- a/src/main/java/no/bioforsk/vips/model/naerstadmodel/NaerstadModel.java
+++ b/src/main/java/no/bioforsk/vips/model/naerstadmodel/NaerstadModel.java
@@ -21,7 +21,6 @@ package no.bioforsk.vips.model.naerstadmodel;
 import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.Calendar;
-import java.util.Collection;
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
@@ -52,12 +51,12 @@ public class NaerstadModel extends I18nImpl implements Model{
     
     private boolean DEBUG = false;
     
-    private Collection<WeatherObservation> TM;
-    private Collection<WeatherObservation> UM;
-    private Collection<WeatherObservation> RR;
+    private List<WeatherObservation> TM;
+    private List<WeatherObservation> UM;
+    private List<WeatherObservation> RR;
     //private Collection<KlimaTimeverdiBO> FM2;
-    private Collection<WeatherObservation> Q0;
-    private Collection<WeatherObservation> BT;
+    private List<WeatherObservation> Q0;
+    private List<WeatherObservation> BT;
     private Date calculationStart;
     private Date calculationEnd;
 
@@ -265,9 +264,8 @@ public class NaerstadModel extends I18nImpl implements Model{
         initCollections();
         ObjectMapper mapper = new ObjectMapper();
         
-        this.calculationStart = mapper.convertValue(config.getConfigParameter("calculationStart"), new TypeReference<Date>(){});
-        this.calculationEnd = mapper.convertValue(config.getConfigParameter("calculationEnd"), new TypeReference<Date>(){});
-
+        
+        
         List<WeatherObservation> observations = mapper.convertValue(config.getConfigParameter("observations"), new TypeReference<List<WeatherObservation>>(){});
         for(WeatherObservation o:observations)
         {
@@ -304,6 +302,25 @@ public class NaerstadModel extends I18nImpl implements Model{
             throw new ConfigValidationException("Minimum number of weather data = " + minimumNumberOfWeatherData);
         }
         
+        // CalculationStart and calculationEnd is by default the start and end of weather data
+        Collections.sort(this.TM);
+        if(config.getConfigParameter("calculationStart") != null)
+        {
+            this.calculationStart = mapper.convertValue(config.getConfigParameter("calculationStart"), new TypeReference<Date>(){});
+        }
+        else
+        {
+            this.calculationStart = this.TM.get(0).getTimeMeasured();
+        }
+        if(config.getConfigParameter("calculationEnd") != null)
+        {
+            this.calculationEnd = mapper.convertValue(config.getConfigParameter("calculationEnd"), new TypeReference<Date>(){});
+        }
+        else
+        {
+            this.calculationEnd = this.TM.get(this.TM.size()-1).getTimeMeasured();
+        }
+        
     }
     
     /**
@@ -603,7 +620,7 @@ public class NaerstadModel extends I18nImpl implements Model{
 
     @Override
     public String getLicense() {
-        return "Copyright (c) 2013 Bioforsk <http://www.bioforsk.no/>. \n" +
+        return "Copyright (c) 2013-2014 Bioforsk <http://www.bioforsk.no/>. \n" +
             " \n" +
             " This file is part of VIPS/NaerstadModel \n" +
             " VIPS/NaerstadModel is free software: you can redistribute it and/or modify\n" +
diff --git a/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts.properties b/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts.properties
index e1fd02a99ff7c76aa2f03f06cae16c6a5c4a08af..0acefe4d8dedc2ce23710cfb66c1c91f3530e0a7 100644
--- a/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts.properties
+++ b/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts.properties
@@ -17,5 +17,5 @@
 
 
 name=Naerstad Model
-usage=The following input data are required:\ncalculationStart - the time when calculation should start\ncalculationEnd - the time whe calculation should end (TODO: Is this necessary?)\nobservations - array of weather observations. An observation consists of:\n\ttimeMeasured - timestamp for observation\n\telementMeasurementTypeId - Code for parameter\n\tlogIntervalId: 1 for hour value\n\tvalue: the observed value\nFour different weather parameters should be provided:\n* TM - Mean temperature (Deg. Celcius)\n* RR - Aggregated rainfall (Millimeters)\n* Q0 - Global radiation (Wh/m2)\n* BT - Leaf wetness\nThey should all be hourly values, they should all be complete hourly series in the exact same period. \nMinimum period length is 4 days (TODO: Verify!)
+usage=The following input data are required:\nobservations - array of weather observations. An observation consists of:\n\ttimeMeasured - timestamp for observation\n\telementMeasurementTypeId - Code for parameter\n\tlogIntervalId: 1 for hour value\n\tvalue: the observed value\nFour different weather parameters should be provided:\n* TM - Mean temperature (Deg. Celcius)\n* RR - Aggregated rainfall (Millimeters)\n* Q0 - Global radiation (Wh/m2)\n* BT - Leaf wetness\nThey should all be hourly values, they should all be complete hourly series in the exact same period. \nMinimum period length is 4 days (TODO: Verify!)\nThe following input data are optional:\ncalculationStart - the time when calculation should start\ncalculationEnd - the time whe calculation should end \n
 description=The N\u00e6rstad model\n\nThe N\u00e6rstad potato late blight forecasting model predicts how conducive the weather is for spore production and subsequent spore release, spore survival and infection. The model consists of sub models for the different steps in the disease cycle like spore production, spore release, spore survival and infection of spores. The model's criteria for spore production are long humid periods and at moderate humidity sporulation is reduced. The amount of viable attached sporangia is reduced by drought, and some spores are washed off during rain. The model criteria for spore release into the air are a drop in humidity or increased radiation, but the release is inhibited by high leaf wetness. The model includes criteria for spore survival and the viability of released spores is strongly inhibited by solar radiation. The spore load is also reduced by precipitation. The criteria for infection are that the leaf wetness duration has to be sufficient for the spores to germinate and infect. The risk of blight development is a function of the amount of viable released spores and the duration of leaf wetness.\n\nThe N\u00e6rstad model has been developed by Ragnhild N\u00e6rstad 
diff --git a/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts_nb.properties b/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts_nb.properties
index 6540ded8b9395125887a4ac5935389783660b652..4b56f92d0fb14d7416057448ea425aa76ccc8ed1 100644
--- a/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts_nb.properties
+++ b/src/main/resources/no/bioforsk/vips/model/naerstadmodel/texts_nb.properties
@@ -16,5 +16,5 @@
 #    along with VIPS/NaerstadModel.  If not, see <http://www.gnu.org/licenses/>.
 
 name=N\u00e6rstads modell
-usage=F\u00f8lgende input kreves:\ncalculationStart - tidspunktet fra n\u00e5r beregningen skal starte\ncalculationEnd - hvor langt fram i tid beregningen skal g\u00e5\nobservations - array (liste) over m\u00e5ledata. En observasjon best\u00e5r av:\n\ttimeMeasured - m\u00e5leverdiens tidsstempel\n\telementMeasurementTypeId - kode for m\u00e5leparameter\n\tlogIntervalId: 1 for timeverdi\n\tvalue: verdien p\u00e5 den m\u00e5lte parameteren\nFire forskjellige m\u00e5leparametre m\u00e5 sendes inn:\n* TM - Middeltemperatur (Celcius)\n* RR - Aggrebert nedb\u00f8r (Millimeter)\n* Q0 - Globalstr\u00e5ling (Wh/m2)\n* BT - Bladfukt (antall minutter/time)\nDisse m\u00e5 alle v\u00e6re timedata. De m\u00e5 alle v\u00e6re komplette tidsserier i eksakt samme periode.\nMinimum lengde p\u00e5 tidsserie: 4 dager.
+usage=F\u00f8lgende input kreves:\nobservations - array (liste) over m\u00e5ledata. En observasjon best\u00e5r av:\n\ttimeMeasured - m\u00e5leverdiens tidsstempel\n\telementMeasurementTypeId - kode for m\u00e5leparameter\n\tlogIntervalId: 1 for timeverdi\n\tvalue: verdien p\u00e5 den m\u00e5lte parameteren\nFire forskjellige m\u00e5leparametre m\u00e5 sendes inn:\n* TM - Middeltemperatur (Celcius)\n* RR - Aggrebert nedb\u00f8r (Millimeter)\n* Q0 - Globalstr\u00e5ling (Wh/m2)\n* BT - Bladfukt (antall minutter/time)\nDisse m\u00e5 alle v\u00e6re timedata. De m\u00e5 alle v\u00e6re komplette tidsserier i eksakt samme periode.\nMinimum lengde p\u00e5 tidsserie: 4 dager.\n\nF\u00f8lgende input er valgfritt:\n\ncalculationStart - tidspunktet fra n\u00e5r beregningen skal starte\ncalculationEnd - hvor langt fram i tid beregningen skal g\u00e5
 description=Om modellen\n\nModellen er laget av forsker Ragnhild N\u00e6rstad, Bioforsk Plantehelse, p\u00e5 grunnlag av resultatene fra forskingsprosjektet NORPHYT. Modellen beregner risikoen for sporeproduksjon med p\u00e5f\u00f8lgende spredning, overlevelse og infeksjon p\u00e5 grunnlag av klimadata. For at infeksjonen virkelig skal skje m\u00e5 det v\u00e6re smitte til stede.\n\nDen nye t\u00f8rr\u00e5te modellen er basert p\u00e5 fors\u00f8k over flere \u00e5r hvor testplanter av potet, dyrket i veksthus, har blitt eksponert et d\u00f8gn for smitte fra andre potetplanter i et potetfelt med t\u00f8rr\u00e5te p\u00e5 friland. T\u00f8rr\u00e5teangrepet p\u00e5 disse testplantene har blitt sammenholdt med v\u00e6rforholdene de dagene de er eksponert. P\u00e5 basis av dette er det laget en modell. Modellen beregner hvor gunstig klimaet er for sporeproduksjon med p\u00e5f\u00f8lgende sporespredning, overlevelse og infeksjon av sporene. Modellen er laget slik at risikotallene \u00f8ker med angrepet i testplantene. Terskelverdien p\u00e5 2,5, som gj\u00f8r at varslet blir r\u00f8dt, tilsvarer at det i gjennomsnitt ble en t\u00f8rr\u00e5teflekk per testplante eksponert i potetfeltet som hadde mye smitte. H\u00f8ye verdier betyr at v\u00e6rforholdene gir stor risiko for infeksjon hvis det er smitte til stede.\nData\n\nModellen bruker f\u00f8lgende parametere som timeverdier:\n\n    Lufttemperatur i 2m h\u00f8gde(TM)\n    Relativ luftfuktighet i 2m h\u00f8gde(UM)\n    Nedb\u00f8r, mm (RR)\n    Vind i 2m h\u00f8gde(FM2)\n    Vind i 10m h\u00f8gde(FF)\n    Netto str\u00e5ling, Wh/m2\n    Kortb\u00f8lget globalstr\u00e5ling, Wh/m2 (Q0)\n    Bladfuktighet i 2m h\u00f8gde, minutter/t (BT)\n    Metningstrykk=0.61078*EKSP(17.269* TM /(TM +237.3)), kP\n\nSporeproduksjon\n\nDet m\u00e5 v\u00e6re fuktig, med metningsdeficit under 220 Pa (over ca 90 % luftfuktighet), i minimum 87 timegrader for \u00e5 sette i gang sporeproduksjonen. Jo lenger fuktperioden er jo mer sporer blir produsert. Ved metningsdeficit mellom 220 og 520 Pa reduseres sporeproduksjonen, og ved metningsdeficit over 520 Pa stopper den. Ved dette vanndamptrykket t\u00f8rker sporeb\u00e6rerne inn.\nSporespredning og sporeoverlevelse\n\nSporene spres ut i luften n\u00e5r luftfuktigheten synker. Fritt vann p\u00e5 bladene hemmer sporespredning til luft. Regn vasker ned en del av sporene. Ved sterkt sollys d\u00f8r en stor andel av de frigitte sporene. En time med sterkt sollys dreper ca 95 % av de eksponerte sporene.\nRisiko for t\u00f8rr\u00e5te\n\nSporene trenger fritt vann for \u00e5 spire, enten fra nedb\u00f8r eller dugg. Det m\u00e5 v\u00e6re v\u00e5tt p\u00e5 bladene i minimum 40 timegrader for at sporene skal rekke og b\u00e5de spire og infisere. Jo lenger den v\u00e5te perioden er jo h\u00f8yere andel av sporene rekker \u00e5 infisere.\nRisiko for t\u00f8rr\u00e5te beregnes slik:\nRisiko= (TSWH(t) /40)*VRS(t) *IR(t)\nTSWH(t) =temperatursum for timer med bladfukt\nVRS(t) =tilgjengelige sporer som er spredt\nIR(t) = Infeksjonsrisiko\n\nN\u00e5r Risiko < 1 settes varselsymbolet til gr\u00f8nt\nN\u00e5r Risiko er mellom 1 - 2,5 settes varselsymbolet til gult\nN\u00e5r Risiko > 2,5 settes varselsymbolet til r\u00f8dt