The scorched and die-back portion of tissue is very slow to dry so that it does not crumble easily. Boron deficiency also causes scorching of new leaf tips and die-back of growing points, but calcium deficiency does not promote the growth of lateral shoots and short internodes as does boron deficiency. The chlorotic interveinal yellow patches usually occur toward the center of the leaf with the margins being the last to turn yellow. In some crops, the interveinal yellow patches are followed by necrotic spots or patches and marginal scorching of the leaves. Resembles nitrogen deficiency in that older leaves become yellowish green and the stems become thin, hard, and woody.
Some plants show colorful orange and red tints rather than yellowing.
The stems, although hard and woody, increase in length but not in diameter. The chlorotic mottling on immature leaves may start first near the bases of the leaflets so that in effect the middle of the leaf appears to have a yellow streak. On fruiting plants, the blossom buds often do not fully develop and turn yellow or abort. As the deficiency becomes more severe, the new growth becomes completely yellow but, in contrast to iron necrotic spots, usually appear in the interveinal tissue. In some plants, the interveinal chloratic mottling first appears on the older leaves and in others, it appears on the immature leaves.