Gnats or fruit flies are everywhere and are naturally attracted by the moisture in the plants, similar to other produce sitting out on your kitchen counter. They are a harmless nuisance so please do not spray any insecticide on the Cat Grass! They can be easily removed by taking the plants outside and giving them a few brisk shakes. Once the gnats have flown off you can place the plants in the refrigerator briefly, which will help prevent them from returning.
Also, make sure you’re not over-watering or allowing the pots of Cat Grass to remain in standing water, as that will only attract more gnats. Remember, soaking the pot in an inch of water for about an hour twice per week should suffice.