A few steps from my back porch, close to my kitchen and in a sunny spot of the yard, I’m growing herbs outdoors — in January. I use a simple season-extension device known as a low tunnel to harvest fresh herbs even in the coldest, darkest months of my Kansas climate.
Rather than digging up all the summertime herbs and transplanting them into pots for wintering over indoors (where herbs begin to look anemic after about a month), I use a low tunnel to protect the plants in my existing kitchen herb garden. My low tunnel is a rectangle of 3-mil heavy-duty plastic held above the herbs by a few hoops of CPVC pipes with their ends stuck into the ground. The edges of the plastic are held down with sticks and old bricks. Learn more about this easy DIY project in Low Tunnel Construction: How to Build a Mini Hoop House.
My low tunnel for herbs measures just 3 feet wide by 6 feet long. Inside are sage (only marginally hardy when unprotected in Zone 5b), parsley, marjoram, sorrel, two varieties of thyme and a few rogue seedlings of garlic chives. Often, in late fall, small dill plants will sprout inside the low tunnel. These short seedlings can survive all winter there, but typically last only a few weeks until I harvest them — and fresh dill from the kitchen herb garden in December is a luxury. Parsley plants started from seed in late summer can be transplanted into the tunnel in September, giving the roots time to establish before the first freeze. Other savory plants that can be harvested all winter from my low tunnel are sorrel and Egyptian walking onions. (I also supplement the tunnel-protected plants with rosemary grown in a container and moved indoors before the first frost.)