I made my own grass and dirt for a custom biome and was playing around to see if they function normally. But I noticed I couldn't plant any type of sapling on either my grass or dirt. So I went looking to see which method allowed this to happen, but I could not find anything in the BlockGrass or BlockDirt classes. Does anyone know the solution to this. Here is all the code pertaining to the two.

public static Block customgrass;
public static Block customdirt;

	customgrass= new BlockCustomGrass(237).setHardness(0.6F).setStepSound(Block.soundGrassFootstep).setUnlocalizedName("customgrass");
	LanguageRegistry.addName(customgrass, "Magic Grass");
	GameRegistry.registerBlock(customgrass, "customgrass");
	MinecraftForge.setBlockHarvestLevel(customgrass, "shovel", 1);
	customdirt= new BlockCustomDirt(238, Material.ground).setHardness(0.5F).setResistance(0.5F).setStepSound(Block.soundGrassFootstep).setUnlocalizedName("customdirt");
	LanguageRegistry.addName(customdirt, "Magic Dirt");
	GameRegistry.registerBlock(customdirt, "customdirt");
	MinecraftForge.setBlockHarvestLevel(customdirt, "shovel", 1);

 

public class BlockCustomGrass extends Block
{
    @SideOnly(Side.CLIENT)
    private Icon iconGrassTop;
    @SideOnly(Side.CLIENT)
    private Icon iconGrassSide;
    private Icon iconSnowSide;

    public BlockCustomGrass(int par1)
    {
        super(par1, Material.grass);
        this.setTickRandomly(true);
        this.setCreativeTab(MagicElementsMod.Misc);
    }

    @SideOnly(Side.CLIENT)
    public Icon getIcon(int par1, int par2)
    {
        return par1 == 1 ? this.iconGrassTop : (par1 == 0 ? MagicElementsMod.customgrass.getBlockTextureFromSide(par1) : this.blockIcon);
    }
    
    public void updateTick(World par1World, int par2, int par3, int par4, Random par5Random)
    {
        if (!par1World.isRemote)
        {
            if (par1World.getBlockLightValue(par2, par3 + 1, par4) < 4 && par1World.getBlockLightOpacity(par2, par3 + 1, par4) > 2)
            {
                par1World.setBlock(par2, par3, par4, MagicElementsMod.customdirt.blockID);
            }
            else if (par1World.getBlockLightValue(par2, par3 + 1, par4) >= 9)
            {
                for (int l = 0; l < 4; ++l)
                {
                    int i1 = par2 + par5Random.nextInt(3) - 1;
                    int j1 = par3 + par5Random.nextInt(5) - 3;
                    int k1 = par4 + par5Random.nextInt(3) - 1;
                    int l1 = par1World.getBlockId(i1, j1 + 1, k1);

                    if (par1World.getBlockId(i1, j1, k1) == MagicElementsMod.customdirt.blockID && par1World.getBlockLightValue(i1, j1 + 1, k1) >= 4 && par1World.getBlockLightOpacity(i1, j1 + 1, k1) <= 2)
                    {
                        par1World.setBlock(i1, j1, k1, MagicElementsMod.customgrass.blockID);
                    }
                }
            }
        }
    }

    public int idDropped(int par1, Random par2Random, int par3)
    {
        return MagicElementsMod.customdirt.idDropped(0, par2Random, par3);
    }
    
    @Override
    @SideOnly(Side.CLIENT)
    public Icon getBlockTexture(IBlockAccess par1IBlockAccess, int par2, int par3, int par4, int par5)
    {
        if (par5 == 1)
        {
            return this.iconGrassTop;
        }
        else if (par5 == 0)
        {
            return MagicElementsMod.customdirt.getBlockTextureFromSide(par5);
        }
        else
        {
            Material material = par1IBlockAccess.getBlockMaterial(par2, par3 + 1, par4);
            return material != Material.snow && material != Material.craftedSnow ? this.blockIcon : this.iconSnowSide;
        }
    }

    @Override
    @SideOnly(Side.CLIENT)
    public void registerIcons(IconRegister par1IconRegister)
    {
        this.blockIcon = par1IconRegister.registerIcon("magicelements:customgrass_side");
        this.iconGrassTop = par1IconRegister.registerIcon("magicelements:customgrass_top");
        this.iconGrassSide = par1IconRegister.registerIcon("magicelements:customgrass_side");
    }
}

 

public class BlockCustomDirt extends Block
{

public BlockCustomDirt(int par1, Material par2Material)
{
	super(par1, par2Material);
	this.setCreativeTab(MagicElementsMod.Misc);
}

@SideOnly(Side.CLIENT)
public void registerIcons(IconRegister ir)
{
	this.blockIcon = ir.registerIcon("magicelements" + ":" + getUnlocalizedName().substring(5));
}
}

Well I've figured out that I must use this method but I'm not sure how to make it so only saplings are allowed to be planted.

public boolean canSustainPlant(World world, int x, int y, int z, ForgeDirection direction, IPlantable plant)
{

}

Something like

 

   

return plant instanceof BlockSapling;

 

Okay well this solved half of the problem but now I can't plant them on my custom dirt.