I just remember that the render type needs to register to mod bus. In this case, crops and flowers should use RenderType.getCutOut() in RenderTypeLookUp.setRenderLayer() method. I register my blocks in GensokyoOntology.java.
 
	GensokyoOntology.java:
 
@Mod.EventBusSubscriber(bus = Mod.EventBusSubscriber.Bus.MOD,value = Dist.CLIENT)
    public static class RenderTypeRegistry {
        @SubscribeEvent
        public static void onRenderTypeSetUp(FMLClientSetupEvent event){
            
				// Render transparent textures to block model like #cross and crop
            event.enqueueWork(() -> {
                RenderTypeLookup.setRenderLayer(BlockRegistry.LYCORIS_RADIATA.get(),
                        RenderType.getCutout());
                RenderTypeLookup.setRenderLayer(BlockRegistry.ONION_CROP_BLOCK.get(),
                        RenderType.getCutout());
            });
        }