I planted some Packman broccoli plants 56 days ago. The biggest head I have is 4" diameter. I read that Packman is supposed to get 9" diameter in 52 days. Can I go ahead and harvest the 4" head?
The key to correct timing on broccoli harvest is not necessarily the size or diameter of the head, but rather the stage of development of the flower buds within the head. You can allow the head to continue to grow as long as the buds are relatively tight and don't open to reveal their yellow flowers. The heads can be harvested at 4 inches in diameter even if the buds aren't fully developed, but you may want to let them continue to grow if they aren't fully developed. After cutting off this first, main head, smaller side shoots should develop that can be harvested until the weather turns too hot.