I'm currently making a grass like block. I've setup it so that plants can grow on it and such but I'm also trying to figure out how to make the grass block spread to my dirt block as well. I feel like it has something to do with the updateTick but I'm not 100% sure. My code for my grass block is as follows.
 

package com.mja00.whyMod.blocks;

import java.util.Random;

import javax.annotation.Nonnull;

import com.mja00.whyMod.init.ModBlocks;

import net.minecraft.block.SoundType;
import net.minecraft.block.material.Material;
import net.minecraft.block.state.IBlockState;
import net.minecraft.init.Blocks;
import net.minecraft.item.Item;
import net.minecraft.world.World;
import net.minecraft.item.ItemStack;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.IBlockAccess;
import net.minecraftforge.common.EnumPlantType;
import net.minecraftforge.common.IPlantable;
import net.minecraftforge.fml.common.Mod;

public class GrussBlock extends BlockBase {

	public GrussBlock(String name, Material material) {
		super(name, material);
		
		setSoundType(SoundType.GROUND);
		setHardness(0.5f);
		setResistance(2.5f);
		setHarvestLevel("shovel", 0);
	}
	
	@Override
	public Item getItemDropped(IBlockState state, Random rand, int fortune) {
		return ModBlocks.DURT.getItemDropped(state, rand, 1);
	}

	@Override
	public void updateTick(World world, BlockPos pos, IBlockState state, Random rand){

	}
	
	
	@Override
	public boolean canSustainPlant(IBlockState state, IBlockAccess world, BlockPos pos, EnumFacing direction, IPlantable plantable)
	{
		IBlockState plant = plantable.getPlant(world, pos.offset(direction));
		net.minecraftforge.common.EnumPlantType plantType = plantable.getPlantType(world, pos.offset(direction));

		if(plant.getBlock() == Blocks.SAPLING)
			return true;

		if(plantType == EnumPlantType.Plains)
			return true;

		return false;
	}
	

}

I'm just stuck and need a little guidance. 

I've figured it out. For anyone looking for the same thing in the future here's the code I grabbed from Mycelium: 

 

public void updateTick(World worldIn, BlockPos pos, IBlockState state, Random rand)
    {
        if (!worldIn.isRemote)
        {
            if (!worldIn.isAreaLoaded(pos, 2)) return; // Forge: prevent loading unloaded chunks when checking neighbor's light and spreading
            if (worldIn.getLightFromNeighbors(pos.up()) < 4 && worldIn.getBlockState(pos.up()).getLightOpacity(worldIn, pos.up()) > 2)
            {
                worldIn.setBlockState(pos, Blocks.DIRT.getDefaultState().withProperty(BlockDirt.VARIANT, BlockDirt.DirtType.DIRT));
            }
            else
            {
                if (worldIn.getLightFromNeighbors(pos.up()) >= 9)
                {
                    for (int i = 0; i < 4; ++i)
                    {
                        BlockPos blockpos = pos.add(rand.nextInt(3) - 1, rand.nextInt(5) - 3, rand.nextInt(3) - 1);
                        IBlockState iblockstate = worldIn.getBlockState(blockpos);
                        IBlockState iblockstate1 = worldIn.getBlockState(blockpos.up());

                        if (iblockstate.getBlock() == Blocks.DIRT && iblockstate.getValue(BlockDirt.VARIANT) == BlockDirt.DirtType.DIRT && worldIn.getLightFromNeighbors(blockpos.up()) >= 4 && iblockstate1.getLightOpacity(worldIn, blockpos.up()) <= 2)
                        {
                            worldIn.setBlockState(blockpos, this.getDefaultState());
                        }
                    }
                }
            }
        }
    }

Thanks to wags#8551 and Laike Endaril#7693 on the MMD Discord for the help.