diff --git a/src/TimeGrid.js b/src/TimeGrid.js
index 8d27bf335..7ab99fc26 100644
--- a/src/TimeGrid.js
+++ b/src/TimeGrid.js
@@ -3,6 +3,7 @@ import cn from 'classnames'
 import raf from 'dom-helpers/util/requestAnimationFrame'
 import React, { Component } from 'react'
 import { findDOMNode } from 'react-dom'
+import memoize from 'memoize-one'
 
 import dates from './utils/dates'
 import DayColumn from './DayColumn'
@@ -65,8 +66,6 @@ export default class TimeGrid extends Component {
     this.state = { gutterWidth: undefined, isOverflowing: null }
 
     this.scrollRef = React.createRef()
-
-    this.resources = Resources(props.resources, props.accessors)
   }
 
   componentWillMount() {
@@ -95,6 +94,7 @@ export default class TimeGrid extends Component {
     raf.cancel(this.rafHandle)
     this.rafHandle = raf(this.checkOverflow)
   }
+  
   componentWillUnmount() {
     window.removeEventListener('resize', this.handleResize)
 
@@ -144,9 +144,10 @@ export default class TimeGrid extends Component {
   renderEvents(range, events, now) {
     let { min, max, components, accessors, localizer } = this.props
 
-    const groupedEvents = this.resources.groupEvents(events)
+    const resources = this.memoizedResources(this.props.resources, accessors)
+    const groupedEvents = resources.groupEvents(events) 
 
-    return this.resources.map(([id, resource], i) =>
+    return resources.map(([id, resource], i) =>
       range.map((date, jj) => {
         let daysEvents = (groupedEvents.get(id) || []).filter(event =>
           dates.inRange(
@@ -233,7 +234,7 @@ export default class TimeGrid extends Component {
           getNow={getNow}
           localizer={localizer}
           selected={selected}
-          resources={this.resources}
+          resources={this.memoizedResources(resources, accessors)}
           selectable={this.props.selectable}
           accessors={accessors}
           getters={getters}
@@ -314,4 +315,6 @@ export default class TimeGrid extends Component {
       })
     }
   }
+
+  memoizedResources = memoize((resources, accessors) => Resources(resources, accessors))
 }
diff --git a/src/utils/Resources.js b/src/utils/Resources.js
index d598f3e87..17d541459 100644
--- a/src/utils/Resources.js
+++ b/src/utils/Resources.js
@@ -11,6 +11,12 @@ export default function Resources(resources, accessors) {
 
     groupEvents(events) {
       const eventsByResource = new window.Map()
+
+      if (!resources) {
+        // Return all events if resources are not provided
+        eventsByResource.set(NONE, events)
+      }
+      
       events.forEach(event => {
         const id = accessors.resource(event) || NONE
         let resourceEvents = eventsByResource.get(id) || []