Boron is essential for germination of pollen grains and growth of pollen tubes and is essential for seed and cell wall formation. Boron deficiency generally results in stunted plant growth. In most crops the symptoms of boron deficiency are quite specific such as crooked stem in celery, corky core in apples, black heart in beets, hollow heart in peanuts and ringed leaf petioles in cotton. Organic matter is an important source of soil boron. High soil pH also limits boron availability. 10% Boron is recommended primarily for soil application.