What does it do?
Required for building new plant cell walls and encouraging apical growth.
What do you see?
Stunted plant growth with extra lateral growth. Older leaves may develop burnt and chlorotic edges. Deficiency symptoms may resemble other micronutrient issues and may indicate an overall issue.
What can you do?
Foliar spray, if not in flower, with a micronutrient complex like Spray-N-Grow or Mineral Matrix.