Why bother with the control plants if they are not going to be sprayed with gibberellic acid

Gibberellic acid is a natural growth hormone present in plants which helps plants to control growth naturally. Spraying additional gibberellic acid helps to stimulate plant growth. So even if it is not sprayed externally, the natural acid present in the plants still controls the growth.

Explanation:

Gibberellic acid (gibberellin) is naturally found in growing apical regions like the shoots, new young leaves, flowers. In the shoots, it helps to increase the inter-node length and thereby increases elongation of a plant through apical growth. They control the growth by acting as chemical messengers.

Farmers usually spray gibberellic acid during seed germination to accelerate plant growth, budding processes, increase foliage and flowering.  Spraying farms with bioactive gibberellins have led to a huge increase in plant growth leading to the green revolution.

weathering is the answer.