TextField not being added to ScrollView

When I input the following code, the textfields I added are not being displayed in the scrollview:

.h

@interface FirstViewController : UIViewController <UIScrollViewDelegate>
@property (strong, nonatomic) IBOutlet UIScrollView *scrollView;
@property (strong, nonatomic) UITextField *firstField;
@property (strong, nonatomic) UITextField *secondField;
@property (strong, nonatomic) UITextField *thirdField;

.m (viewDidLoad)

self.firstField.placeholder = @"First";
self.firstField.textAlignment = NSTextAlignmentCenter;
self.firstField.font = [UIFont fontWithName:@"Helvetica Neue Light" size:50.0];

self.secondField.placeholder = @"Second";
self.secondField.textAlignment = NSTextAlignmentCenter;
self.secondField.font = [UIFont fontWithName:@"Helvetica Neue Light" size:50.0];

self.thirdField.placeholder = @"Third";
self.thirdField.textAlignment = NSTextAlignmentCenter;
self.thirdField.font = [UIFont fontWithName:@"Helvetica Neue Light" size:50.0];

[self.scrollView addSubview:self.firstField];
[self.firstField autoPinEdgesToSuperviewEdgesWithInsets:UIEdgeInsetsZero excludingEdge:ALEdgeRight];
[self.firstField autoMatchDimension:ALDimensionWidth toDimension:ALDimensionWidth ofView:self.scrollView];
[self.firstField autoMatchDimension:ALDimensionHeight toDimension:ALDimensionHeight ofView:self.scrollView];

[self.scrollView addSubview:self.secondField];
[self.secondField autoPinEdge:ALEdgeLeft toEdge:ALEdgeRight ofView:self.firstField];
[self.secondField autoMatchDimension:ALDimensionWidth toDimension:ALDimensionWidth ofView:self.scrollView];
[self.secondField autoMatchDimension:ALDimensionHeight toDimension:ALDimensionHeight ofView:self.scrollView];

[self.scrollView addSubview:self.thirdField];
[self.thirdField autoPinEdge:ALEdgeLeft toEdge:ALEdgeRight ofView:self.secondField];
[self.thirdField autoPinEdgesToSuperviewEdgesWithInsets:UIEdgeInsetsZero excludingEdge:ALEdgeLeft];
[self.thirdField autoMatchDimension:ALDimensionWidth toDimension:ALDimensionWidth ofView:self.scrollView];
[self.thirdField autoMatchDimension:ALDimensionHeight toDimension:ALDimensionHeight ofView:self.scrollView];

self.automaticallyAdjustsScrollViewInsets = NO;

I have self.scrollView is within a scrollView by the way (in a pageviewcontroller). I am using PureLayout to position the text fields, and I'm pretty sure the way I did it is correct. Is there something I'm missing?