Fill screen with nodes - ios

Question

I'm struggling to find a way to fill the screen with rows and rows of spriteNodes. I can only currently get one solid line like so. Picture of simulator
Bellow is my code, any help with be greatly appreciated.
let world = SKNode()
let ground = Ground()
override func didMoveToView(view: SKView) {
/* Setup your scene here */
self.backgroundColor = UIColor(red: 0.4, green: 0.6, blue: 0.95, alpha: 1)
self.addChild(world)
var groundPosition = CGPoint(x: -self.size.width, y: 600)
let groundSize = CGSize(width: self.size.width * 3, height: 0)
ground.spawn(world, position: groundPosition, size: groundSize)
}
class Ground: SKSpriteNode, GameSprite{
var textureAtlas: SKTextureAtlas = SKTextureAtlas(named: "ground.atlas")
// Property named groundTexture to store current ground texture:
var groundTexture:SKTexture?
func spawn(parentNode: SKNode, position: CGPoint , size: CGSize) {
parentNode.addChild(self)
self.size = size
self.position = position
self.anchorPoint = CGPointMake(0, 1)
//default to the the mud texture
if groundTexture == nil {
groundTexture = textureAtlas.textureNamed("grass")
}
// Repeate the texture
createChildren()
}
//Builds nodes to repeate the ground
func createChildren() {
if var texture = groundTexture{
var tileCount:CGFloat = 0
let textureSize = texture.size()
let tileSize = CGSize(width: 25, height: 15)
// Build nodes until we cover the screen
while tileCount * tileSize.width < self.size.width{
// randomly chooses the texture that will be used
let random = arc4random_uniform(50)
if random < 25{
texture = textureAtlas.textureNamed("grass")
}else{
texture = textureAtlas.textureNamed("mud")
}
let tileNode = SKSpriteNode(texture: texture)
tileNode.size = tileSize
tileNode.position.x = tileCount * tileSize.width
tileNode.anchorPoint = CGPoint(x: 0, y: 1)
self.addChild(tileNode)
tileCount++
}
}
}