How to Chart the Growth of a Sweet Potato

Prepare two growing areas -- they can be side by side or in different areas of the yard or garden. Make both beds about 4 feet wide by 8 feet long. In one, do not amend the soil and leave rocks, weeds and other naturally occurring objects. In the other, spread at least 2 inches of organic compost over the soil surface and dig it in to a depth of 12 inches, removing rocks and weeds as you dig.

Plant your sweet potatoes. Use fresh sweet potatoes and cut them into pieces about 2 inches around, including at least one eye with each piece. Wait until the final spring frost has passed and then make planting holes 8 inches deep and 12 to 18 inches apart in both of your rowing beds. Drop one cut piece of sweet potato into each hole and then cover them with the soil you dug out to make the hole.

Measure the length of the sweet potato vines in both beds and record it on paper or in a graphing software program after two weeks. Make separate columns or sheets to record the growth statistics of the two different beds. Also note the average daily high and low temperatures and how much rain fell or how much you irrigated your plants during this first two-week period.

Measure the length of the vines every two weeks and chart it on your paper or software program. Make a mental note of the differences, if any, between the two planting areas.

Dig one sweet potato from each bed after about two months. Then measure the length and circumference of each and note those numbers on your paper or software program.

Harvest all sweet potatoes in the fall, around the time of your first frost. Keep potatoes from each of your test beds separate, measure the length and circumference of each potato and note those numbers on your paper or software program. Calculate an average size for the potatoes in each bed by adding together all of the lengths and dividing by the number of potatoes you harvested. Do the same for the circumference measurements.

Evaluate the average size of the potatoes from each bed, making note of any significant differences in size between the potatoes you grew in the improved bed and the ones you grew in native soil.