I was creating a farm, (16 * 18) and had my sprinkler system set up and went to plant. I also had Pams Harvestcraft, so I planted a few vanilla crops (wheat, potatoes, carrots) and Pams crops. I was not crossbreeding, just growing in cropsticks. I leave it alone, come back and almost my entire farm was overtaken with weeds. All the sticks had crops in them, and none were crossbreeding sticks. I should say that this is my first time irrigating with sprinklers, I have never had this problem before but all those farms were irrigated the old fashioned way with water blocks. I also planted Witchery Crops

I used the technic launcher for my mods, on Minecraft 1.7.10, Agricraft version 1.5.0, and Pams Harvestcraft version 1.7.10, Witchery version 1.7.10-0.24.1
I did have quite a few other mods but I don't think they effect the issue here

I made quite a few searches on how to prevent weeds, or why the weeds were growing but they all referred to when crossbreeding plants and I was not crossbreeding.

Your environment

• How are you playing?
  • Operating System: Windows
  • Launcher: Technic
  • Modpack: WC Tech & Magic Reborn
• What kind of server:
  • Singleplayer
  • Multiplayer
• Game Modes:
  • Survival
  • Creative
• Save File:
  • Brand new save
  • Only an existing save

1.7.10 is most likely no longer supported. I'd suggest trying 1.12.2's builds.

Yes, 1.7.10 has no longer been supported since a loooong time now.