I'm creating a Visualforce pageBlockTable for some custom fields on an Opportunity record. It works great when data is entered upon creation of an Opportunity record, but any blank fields in the pageBlockTable are inaccessible so I can't create the opportunity and go back to add data into those fields. How can I make blank fields editable in the table?
 

<apex:page standardController="Opportunity">
    <apex:form >
        <apex:pageBlock mode="inlineEdit">
             <apex:pageBlockButtons >
                <apex:commandButton action="{!edit}" id="editButton" value="Edit"/>
                <apex:commandButton action="{!save}" id="saveButton" value="Save"/>
                <apex:commandButton onclick="resetInlineEdit()" id="cancelButton" value="Cancel"/>
                </apex:pageBlockButtons>
            <apex:pageBlocktable value="{!Opportunity.Meal_Date_1__c}" var="Meal_Date_1__c">
                  <apex:column headerValue="Day 1">
                    <apex:inputfield value="{!Opportunity.Meal_Date_1__c}"/>
                    <apex:outputField value="{!Opportunity.Meal_Date_1__c}"/>
                </apex:column>
                <apex:column headerValue="Breakfast">    
                    <apex:inputField value="{!Opportunity.Breakfast_1__c}" />
                </apex:column>
                <apex:column headerValue="Lunch">
                    <apex:inputField value="{!Opportunity.Lunch_1__c}" />
                </apex:column>
                <apex:column headerValue="Dinner">
                    <apex:inputField value="{!Opportunity.Dinner_1__c}" />
                </apex:column>
                <apex:column headerValue="Time">
                    <apex:inputField value="{!Opportunity.Meal_Time_1__c}" />
                </apex:column>
                </apex:pageBlockTable>
                <apex:pageBlockTable value="{!Opportunity.Meal_Date_2__c}" var="Meal_Date_2__c">
                <apex:column headerValue="Day 2">
                    <apex:inputField value="{!Opportunity.Meal_Date_2__c}" />
                </apex:column>
                <apex:column headerValue="Breakfast">    
                    <apex:inputField value="{!Opportunity.Breakfast_2__c}" />
                </apex:column>
                <apex:column headerValue="Lunch">
                    <apex:inputField value="{!Opportunity.Lunch_2__c}" />
                </apex:column>
                <apex:column headerValue="Dinner">
                    <apex:inputField value="{!Opportunity.Dinner_2__c}" />
                </apex:column>
                <apex:column headerValue="Time">
                    <apex:inputField value="{!Opportunity.Meal_Time_2__c}" />
                </apex:column>
                <apex:inlineEditSupport event="ondblClick" 
                        showOnEdit="saveButton,cancelButton" hideOnEdit="editButton" />
                </apex:pageBlockTable>
                <apex:pageBlockTable value="{!Opportunity.Meal_Date_3__c}" var="Meal_Date_3__c">
                <apex:column headerValue="Day 3">
                    <apex:inputField value="{!Opportunity.Meal_Date_3__c}" />
                </apex:column>
                <apex:column headerValue="Breakfast">    
                    <apex:inputField value="{!Opportunity.Breakfast_3__c}" />
                </apex:column>
                <apex:column headerValue="Lunch">
                    <apex:inputField value="{!Opportunity.Lunch_3__c}" />
                </apex:column>
                <apex:column headerValue="Dinner">
                    <apex:inputField value="{!Opportunity.Dinner_3__c}" />
                </apex:column>
                <apex:column headerValue="Time">
                    <apex:inputField value="{!Opportunity.Meal_Time_3__c}" />
                </apex:column>
                <apex:inlineEditSupport event="ondblClick" 
                        showOnEdit="saveButton,cancelButton" hideOnEdit="editButton" />
                </apex:pageBlockTable>
                <apex:pageBlockTable value="{!Opportunity.Meal_Date_4__c}" var="Meal_Date_4__c">
                <apex:column headerValue="Day 4">
                    <apex:inputField value="{!Opportunity.Meal_Date_4__c}" />
                </apex:column>
                <apex:column headerValue="Breakfast">    
                    <apex:inputField value="{!Opportunity.Breakfast_4__c}" />
                </apex:column>
                <apex:column headerValue="Lunch">
                    <apex:inputField value="{!Opportunity.Lunch_4__c}" />
                </apex:column>
                <apex:column headerValue="Dinner">
                    <apex:inputField value="{!Opportunity.Dinner_4__c}" />
                </apex:column>
                <apex:column headerValue="Time">
                    <apex:inputField value="{!Opportunity.Meal_Time_4__c}" />
                </apex:column>
                <apex:inlineEditSupport event="ondblClick" 
                        showOnEdit="saveButton,cancelButton" hideOnEdit="editButton" />
                </apex:pageBlockTable>
        </apex:pageBlock>
    </apex:form>
</apex:page>