Doubles or singles...

One thing I have noticed when counting the emerging plants is that I count more than 50 beetroot plants. This odd since there are only 50 seeds...

When I asked I was told this happens. Any idea why?

Part of my temperature experiment is to find out how many seeds will produce two plants. So every two days I pick out all the beetroot plants and seeds from the soil and count the doubles.

Unfortunately I am discovering that once the plant discards the seed the doubles then become singles (the seed is the link that holds them together). The trick is to check the emerging plants before this happens. A lot of trialling to find this moment.

Once the pant can fend for itself it gets rid of the green seed

The plants taken from the soil to check for doubles

This experiment will need to be adapted. Do I count everyday? Or do I put each seed in its own container so I can see if one seed will produce two plants or one? How else could I find out?