If you´re planting in the ground or in a garden bed, you can just draw up a schematic and note where you planted each variety.  I did that in a pretty big raised bed, and it´s been helpful. I used some white cloth bags and had labeled those with a sharpie, which has disappeared on many of them, i guess from either sun or water or both....so, there might be something to your concerns re: chemicals leaching into the soil.  I´m not worried; i´m gonna eat those chiles anyway.  I probably ate a few markers back in the late 70s/early 80s anyway. But yeah, the notebook with a labeled schematic of the plot has worked for me.