Beans are very sensitive to boron and should not be grown in a field where boron was applied to rutabagas, sugar beets or forages in the previous year.
Boron is needed only in very small quantities, and since an overdose is toxic, take extreme care in its use. Boron deficiency has not been diagnosed in cereals, peas or beans in Ontario, and boron applications to these crops — or applied to other crops in the year preceding them — can be toxic. Boron should be broadcast; not banded at seeding.
Although labs provide soil tests for boron, these tests are not accredited by OMAFRA because they have not been found to contribute to better fertilizer guidelines. Plant analysis is generally a better indicator of boron deficiency.