In almanac gardening the last stretch before new moon is the barren quarter. Plant nothing. Go after the weeds.

The four almanac quarters each get a job: leafy crops, then seeded crops, then roots, then destruction. The fourth is for weeding, pest control, tilling and turning compost, on the reasoning that whatever you cut back now stays back. It hands a gardener a fortnightly rhythm, which is more than most gardening advice manages.