(Image from: https://hudsonvalleyseed.com/products/italian-large-leaf-basil?_pos=1&_psq=italian%20large&_ss=e&_v=1.0)
Growing Instructions for Italian Large Leaf Basil:
Direct sow after frost, or start indoors up to 1 month before last frost date. To have fresh basil the whole season, start in succession at one-month intervals. Pinch off tallest growth in order to keep basil from flowering; flavor becomes too strong once in bloom. Good for garden or container plantings.
(from Hudson Valley Seed Company website)