Yes, just manually remove them and be sure you get all of them. Some are very, very tiny. I cut the sponges in half vertically so it looks like an open book. That's so the roots on the new weeds can grow downward easier. You can also see if you got all the seeds freom thye AG seed kit out of the sponges.how do i get the seeds out of the little stirofoam thing that comes in the plants. are they already out or do i have to manually take em out? how do i do this?