How can you tell when sweet potatoes are ready to dig up?

Answer 1

Most potato varieties are ready to dig in 95 to 110 days after planting.
You will know your potatoes are finished and ready to dig when they begin to yellow.
Let your potatoes dry at least for the day on the soil or on the grass or on drying tables or trays. Under a shade tree for a couple of days if they didn't dry enough in a day.
http://www.industryinet.com/~ruby/potatoes.html

Starting in late summer, you can remove some developing roots while leaving the plant in place. Harvest the main crop of sweet potatoes around the time of the first frost in the fall. Dig below the level of the ridge and gradually move closer toward the plants, removing soil until the fat roots are exposed. Carefully dig under these roots to gauge the depth to dig as you go down the row.

Ideally, the roots should be allowed to dry on the ground for 2 to 3 hours, then placed in a warm room for curing (85°F and 85 percent humidity (if possible) for 10 to 14 days and then stored in a cool (55°F) location. In case of frost, cut the vines from the roots immediately to prevent decay spreading from the vines to the roots and dig sweet potatoes as soon as possible. Cold soil temperatures quickly lessen the roots’ ability to keep in storage.
http://www.urbanext.uiuc.edu/veggies/sweetpotato1.html

Good Luck! Hope this is helpful.

Answer 2

When the leaves wilt, the sweet potatoes should be ready. There are a number of ways to address bugs, but the easiest and lowest rick approach is to plant marigolds around the bases of your other plants, which have a smell that drives away most non-beneficial bugs. If you have aphids (those tiny green bugs that appears in large numbers) you really need a commercial spray. Japanese beatles (half inch in size, black with an oily/rainbow hue) there is little you can do besdies buy the traps every garden center sells for them.

Answer 3

Dig one up and look.