Test Tube Hydroponics

This was a great kit for a lesson on hydroponics. I taught it to 5th graders with about 24-26 students per class in 3 sections. A couple of hints that you may need to know:
Since every student will plant their own soybean seed in rock wool in a seed starter tray, you'll need to order at least 2 kits for 75 students. I thought I could get by with one kit and a refill kit. The refill kit does not come with the seed starter trays. If you have your own seed starter trays, that would work too so you could get by with one kit and one refill kit. Another problem I had is that I used permanent markers like it said in the directions to mark student's names on the test tubes. Now I have to find something that will take the permanent marker off to use for next year classes, I haven't found anything as of yet that will take it off. The plant tags may work to use for the test tubes for next time. The directions in the kit say to use the plant markers only to mark the seed that is planted in the rock but I think that they could somehow be used in the test tube too. The last helpful hint would be to give the seeds at least 8-10 days to grow in the rock wool in the seed starter trays before you use them in the test tubes. The soybean roots need to be long enough to reach the nutrient solution.
Otherwise, after learning all this from the first time using this lesson, it will be one that I use every year in the schools in my county. The students and I loved it!