You Can Buy Seed
There are many varieties of carrot you can grow, including:
These and all other kinds of carrot are available as seed. From your local grocery or variety store to the finest seed catalog, you’ll be able to find seed for whichever type of carrot you wish to grow.
Carrots are usually available as heirloom seeds, too. Pollinated instead of being hybridized, and usually both fertile and untreated, heirloom seeds offer an organic option for planting. In addition, many heirloom seeds come in containers that allow them to be stored for long periods of time.
Whether you choose packaged seeds from a store or heirloom seeds, you can buy seeds almost anywhere, and you can expect a good harvest from them no matter which kind you get.
Seeds from Carrots
If you’ve already got carrots growing, you can simply allow them to winter over and bolt, and then harvest the seeds for replanting.
Seeds from Friends
If you have a friend who grows a particular variety of carrot that you like, you could ask that friend to allow one or two carrots to remain in the ground over the winter and then bolt in the spring. Once the plant as gone to seed, you can harvest those seeds and plant them in your own garden. There is nearly no work involved in allowing carrots to winter over and bolt, and you can offer to mulch the plants in the fall, in exchange for the seeds.
Your friend may already have seeds from a previous generation of plants, too. A smart gardener will harvest and save seed when they can, so you may be able to get seed this way exchange for the seeds. And your friend may find it flattering that you enjoyed their carrots so much that you want some of your own!