I can't figure out for the life of me why this isn't working as it was working fine a few months ago, but whenever I try to render a simple item I get the error "Model definition for location x#inventory not found"

Here's the class registering it

package com.bryceclark56.horticulture.Item;

import com.bryceclark56.horticulture.Reference.Reference;
import net.minecraft.client.Minecraft;
import net.minecraft.client.resources.model.ModelBakery;
import net.minecraft.client.resources.model.ModelResourceLocation;
import net.minecraft.item.Item;
import net.minecraftforge.fml.common.registry.GameRegistry;

public class Items
{
    public static final FoodHorticulture lettuce = new FoodHorticulture(6, 2, false).setUnlocalizedName("lettuce");

    public static void registerRenderer(Item item, String name)
    {
        ModelBakery.addVariantName(item, Reference.MOD_ID + ":" + name);
        Minecraft.getMinecraft().getRenderItem().getItemModelMesher().register(item, 0, new ModelResourceLocation(Reference.MOD_ID + ":" + name, "inventory"));
    }

    public static void init()
    {
        GameRegistry.registerItem(lettuce, "lettuce");
    }

    public static void registerModels()
    {
        registerRenderer(lettuce, "lettuce");
    }
}

And the JSON file.

{
  "parent": "builtin/generated",
  "textures": {
    "layer0": "horticulture:items/lettuce"
  },
  "display": {
    "thirdperson": {
      "rotation": [ -90, 0, 0 ],
      "translation": [ 0, 1, -3 ],
      "scale": [ 0.55, 0.55, 0.55 ]
    },
    "firstperson": {
      "rotation": [ 0, -135, 25 ],
      "translation": [ 0, 4, 2 ],
      "scale": [ 1.7, 1.7, 1.7 ]
    }
  }
}

Also worth noting that the renderer is only being registered on the client proxy so that's not the problem.

Do you put the GameRegistry part in preInit and the model part in init?

I'm pretty sure you are supposed to add variants after the original register. Try swapping those lines.

I did have it registered in preinit then the model thing in init, I ended up fixing it though I don't exactly know how... I just started over and it ended up working.

I think you have to do the model bakery in the preInit part of the Client Proxy (if existing) and then ModelMesher part in the init method of the Client Proxy.