First time posting. I'm not a very experienced gardener so your help will be much appreciated. A couple of years ago I started growing my vegetables in very large containers and I replaced all the soil for the new planting season. This past year, I decided not to empty the containers completely because of the cost and the weight of the containers. Today, I finally had the opportunity to plant and discovered that many of the containers are swarming with what appears to be tiny ants. Are they ants? Is this normal if you save the soil? I've read on the forum about others reusing soil and no one mentioned having this as a problem. I'm assuming I need to dump all the containers and wash them down and refill with new soil. What can I do do prevent these ants from returning? I do have a very large yard so I have plenty of places to dump this old soil, but I hate to go thru the cost of refilling and have these ants return. Is there something I can add to the soil to prevent them from returning that is safe with vegetables? I'm sorry this is so long. Thank you in advance