So that was a disappointment, and we didn't try them again for a while. But we love them, and know that they'd be a good addition to a winter market stand, so this year we vowed to try again.
Sweet potatoes are typically planted from what's called a "slip," which is essentially a little seedling, except it sprouts off an old sweet potato rather than from a seed. We ordered ours from a reputable organic supplier in North Carolina with three-day shipping, but an unhappy coincidence of delays meant that they arrived after five days instead of three, and we weren't able to plant them until the day after we got them. They were sorry looking little sprouts, indeed, but we thought we'd give them a shot.
Well, the short story is that they didn't make it. But, undaunted, we decided to give it another try, this time with guaranteed two-day shipping. The slips arrived in good shape, and our two employees were kind enough to agree to come back to the farm after their dinners, when it was cool, to help us plant them out. With the four of us (plus the help of our toddler, whose job was to pull out the poor little dead stems of the first round), we got all six hundred feet re-planted. As there was no rain forecast in the next day, we covered the plants with shade cloth to prevent their drying out. It was a tense little while - our soil is stellar at holding moisture, but a baby plant can only take so much sun, and to water them by hand would be an effort we hoped to avoid. But the rain did come, and they seem to be thriving.
It's too early to bet on rodents, but we've got better soil, better harvesting equipment, and a lot more experience now; with luck, we'll have sweet potatoes for the end of CSA and well into the winter market.