How Many Sweet Potatoes Per Plant?

The short answer

Plan on 2.5 pounds per plant. Some plants hand you two fat roots and a few pencil-thin ones. Others give you five good ones. The weight is the number to plan with, not the count.

• About 2.5 pounds per plant, roughly 3 to 5 storage roots.
• Good soil and a full warm season push a plant toward 4 pounds.
• Cool summers and heavy nitrogen pull it down under 1.5 pounds.
• First time? Plant 10 slips, weigh what you dig, and plan next year off your own number.

It is one dig, not a steady picking

Sweet potatoes are a single-harvest crop. You dig the whole plant once, at about 110 days from planting slips, and that is the entire return. A tomato plant hands you fruit every week for two months. A sweet potato plant hands you one bin, one time.

That 110 days is 20 days longer than a regular potato, which finishes around 90 days. Those 20 days matter if your summer is short. If your last frost is late and your first fall frost is early, you may not have 110 warm days, and the roots will still be small when you have to dig them. In that case plant slips as early as the soil allows, or grow potatoes instead.

How many plants for a family of 4

Work it from 2.5 pounds per plant. Say a family of 4 eats sweet potatoes as a side dish, and one meal takes about 2 pounds. That is 2 pounds per meal for the whole household.

Fresh eating through fall, one meal a week for about 12 weeks, is 24 pounds. At 2.5 pounds per plant that is 10 plants. Round to 10 to 12 slips.

A storage supply that runs from the fall dig into late winter, one meal a week for about 30 weeks, is 60 pounds. At 2.5 pounds per plant that is 24 plants. Round to 24 to 32 slips, which is 60 to 80 pounds. Copy the math with your own meal count and your own number of weeks.

• Fresh eating, family of 4: 10 to 12 plants, about 25 to 30 lb.
• Winter storage, family of 4: 24 to 32 plants, about 60 to 80 lb.
• Per person, that is roughly 3 plants fresh or 7 plants for storage.

Why yields come in low

Sweet potatoes want warm soil and a long season. They are a tropical crop. If your ground is cool at planting, or your summer nights stay in the 50s, the roots never size up no matter how good the vines look.

The other common cause is too much nitrogen. Rich compost and lawn fertilizer grow enormous vines and thin roots. The plant puts its energy into leaves instead of storage. Here is the test: at harvest, if the vines were huge and the roots came out thin and stringy, cut the nitrogen next year and plant into plainer, looser soil.

Hard or rocky ground is the third one. Roots that hit compacted soil come out short and twisted. Loose soil or an 8 inch mound gives you bigger, straighter roots.

• Cool soil and cool nights mean small roots, even with healthy vines.
• Huge vines plus thin roots equals too much nitrogen. Cut it next year.
• Hard soil gives short, twisted roots. Loosen the bed or mound it up.

Curing is what makes the number real

The 2.5 pounds only counts if the roots keep. Fresh-dug sweet potatoes are starchy, not sweet, and their skins are thin and easy to scuff. Uncured, they rot in storage within a few weeks and you lose most of the harvest.

Cure them for about 10 to 14 days somewhere warm and humid, around 80 F. Curing heals the skin and turns starch into sugar, so they taste sweeter and hold for months. Then move them somewhere cool, dark, and dry in a breathable bin. Never the fridge, which makes them hard and off-flavored.

Skip curing and your real yield is not 2.5 pounds a plant. It is whatever you eat in the first three weeks.

Space them 14 inches apart

Set slips 14 inches apart in the row, with 42 inches between rows. The vines run long and wide, so that row spacing gets used.

At that spacing, 24 plants take about 28 feet of row, which is three 10-foot rows. Three rows at 42 inches apart is about 10 feet wide, so roughly 105 square feet for a winter supply for a family of 4. Ten plants for fresh eating take a single 12-foot row.

Get your exact number

Your real count depends on how often your household eats sweet potatoes, how many warm days your ZIP code gives you, and whether you are eating fresh or storing. The planner takes those three and returns the exact number of slips and the row space they need, so you plant 18 or 26 instead of a round guess.