Tina - you might try giving several of the plants a vigorous shake over a white surface, or sheet of white paper or stiff paperboard. Hold the pot or cell pack firmly with one hand, tilt it sort of sideways, and shake the foliage with your other hand over the white surface. It's a great way to check your plants for pests. Do this on several plants from several locations to get a good idea of your pest situation. You'll easily see them crawling around on the white surface. If you do have thrips, there are a couple of beneficial nematodes that do a great job of cleaning up thirps, fungus gnats, and shore flies...they are applied to the soil. They attack these insects during their life stages that inhabit the soil. Bagged soil mixes can have these pests as egg and larval stages. Pasteurization before use will usually kill them off. But as you and others have stated, they can come in on other plants, on your clothing, and on pets.