Ken is known for his soil. He has been building soil for decades. One part of his soil building program is planting green manures. He plants them throughout the season, and plants with weather and crops that have come out and crops that will go in next.
In fall he decides part of the next season's rotation as some green manures die with frost and others will come up in spring and continue to grow. So he plants the ones that die with frost where the early crops will go, and the ones that will come in spring where the later crops will go.
The key is to keep the soil covered so it will not wash away with rain or blow away with wind. And a green manure crop, like mulch, moderates soil temperatures. With fewer extreme swings of heat and cold, the microbes flourish in the soil. Living soil is healthy soil.
I look forward to seeing green manures sprout - they look like a short beard