September and October are the garden’s grand finale. The tomatoes are winding down, but squash, pumpkins, root crops, and cool-season greens are hitting their stride — often sweeter after a light frost.
Harvest winter squash and pumpkins when the rind resists a fingernail and the stem has turned corky. Cut them with a few inches of stem attached, then cure them in a warm, dry spot for ten days. Cured properly, a butternut will keep on a cool shelf until spring. Lift potatoes and onions on a dry day, brush off the dirt, and let them dry in the shade before storing.
Leave roots like carrots, parsnips, and beets in the ground as long as you can — cold soil is the best refrigerator there is, and frost converts their starches to sugar. Mulch them with straw and you can pull fresh carrots well into winter.
As beds empty, do not leave the soil bare. Sow a cover crop of rye or field peas, or blanket beds with shredded leaves. The garden feeds you all season; fall is when you feed the garden back.