Small Corn Experiment

So I planted a small plot of corn seeds on March 17th. The seeds were a mixture of early flour/flint type corn and sweet corn varieties that were grown last year (see the corn project tab). Unfortunately I did not keep track of the total number of seeds planted but I think it was around 50. A few rows of sweet type kernels and the rest flour/flint. I just did a count of the plants that have sprouted. 21 sprouts looks alive and 7 sprouts appear to have been killed by frost. There may be as many as 22+ non-sprouters out there. It looks like there are at least four sprouters from the rows that I remember planting sweet kernels. I think the results are interesting so far and last night may have been the last light frost (fingers and toes crossed!). I hope I will be saving seed from these 21 plants so that I can develop some frost tolerant corn varieties. Probably better to wait till May to plant corn but then what would I do in March and April? The average temperature since planting has been 48.7F according to the nearest weather station which is just to the southwest but at an elevation 61ft above us. The highest temperature has been 71F and the lowest 32F. I'm thinking some years everything may get wiped out by a harder frost if I keep a March 17th planting date but it seems like a cool spring overall thus far.