custom plant assistance

I'm still very new with all this but I've begun to make a new plant with the Minecraft forge mod 1.15.2 and I went through all the tutorials for it except the fourth video and when i go to plant the seeds (after I've done almost everything and i wanted to test it) it comes up as a error block. Not quite sure what i did wrong but i would like some assistance or even tips on to fix this lol that would be very much appreciated!