Can too much nitrogen actually harm a plant instead of helping it? You mix water solutions with seven different nitrogen levels. These range from 0% (plain water) to 10%. You plant bean seeds in perlite and water each group with its assigned solution for two weeks. The results are surprising. The control group with no added nitrogen grew the tallest at 20 cm. The 0.5% and 1% groups grew only 1.5 cm. Every group above 2% nitrogen died completely. This experiment shows that more fertilizer is not always better. Bean plants can be killed by nitrogen doses that seem small.