Reporting
There are several possible

There are several possible causes for the uneven corn in your garden. Weather (too dry or too wet; warm and then a sudden cold spell) or your soil may have low pH. Test the soil and correct low pH by adding limestone . Phosphorus deficiency sometimes caused by wet, cold soil can also cause uneven growth.

Excessive heat is the main reason for loose shaggy broccoli heads. Planting too early in the spring can also cause heads to mature too early. Temperatures below 40 degrees F cause young plants to bolt. Drought conditions or fluctuating moisture will also cause broccoli heads to loosen. Some varieties bolt quicker than others.