Why not try adding Capsacin to the pots or put it on the bulbs before you plant them. The oils don't wash off very easily. It works for squirrels. You normally add it to bird food, because birds don't have taste buds, so it does not burn their tongues like it does to mammals. It has been tested on poultry feed to keep rats away and has been proven to be effective.
Using Cayenne Pepper on Tulip Bulbs-----
Flaming Squirrel Seed Sauce --- and ---
Field evaluation of capsaicin as a rodent aversion agent for poultry feed.
Capsaicin is just thing you can try. There are products like Ritter Critter and other that have smell or taste. Some sprays add a chemical call bitrex, it is added to most home cleaning products to keep children from drinking them. According to their website, 'Bitrex is the brand name of the bitterest substance in the world. Responsible manufacturers and retailers add Bitrex to household products as a safety ingredient.' I have seen it in products to keep animals from eating garden plants. It is created not to wash off very easily.
Non-sprays; You can add chicken wire buried just below the surface of the soil. When the squirrel tries to dig into the pot they encounter something they can't dig through. The larger gauge, so the bulbs can get through easily. Instead of burying it, I would add a layer of pumice or scoria (AKA black pumice) on top of the wire. That allows you the flexibility to remove the wire if you need to get in the pot.
You can buy Coyote or Cougar urine, just add some to the pot. Reapply after it rains.