How to Grow Sweet Potatoes: Complete Step-by-Step Guide

Successfully grow sweet potatoes by starting with healthy slips, planting in warm soil (70-80°F) after the last frost, providing full sun and well-drained soil, watering consistently but not excessively, and harvesting after 90-170 days when leaves begin to yellow. Proper curing after harvest dramatically improves flavor and storage life.

Want to enjoy homegrown sweet potatoes with superior flavor and nutrition? Growing your own is simpler than you think and yields sweeter, more vibrant tubers than store-bought varieties. This comprehensive guide walks you through every step—from selecting the right variety to harvesting your bounty—with actionable advice backed by agricultural research. Whether you have a sprawling garden or just a few containers, you'll learn exactly how to grow sweet potatoes successfully this season.

Why Grow Your Own Sweet Potatoes?

Homegrown sweet potatoes offer distinct advantages over store varieties. They contain up to 30% more beta-carotene when harvested at peak maturity, and their flavor intensifies during proper curing. Unlike commercial varieties bred for shipping durability, home gardeners can select cultivars specifically for taste and texture. Plus, growing your own ensures no chemical treatments or premature harvesting that compromise nutritional value.

Essential Growing Requirements Checklist

Before planting, verify these critical conditions are met:

Climate: Requires 90-170 frost-free days (depending on variety)
Soil temperature: Minimum 65°F at planting time (ideal 70-80°F)
Sun exposure: Minimum 6-8 hours of direct sunlight daily
Soil type: Well-drained, sandy loam with pH 5.8-6.2
Space requirements: 12-18 inches between plants, 36-48 inches between rows

Step 1: Starting Your Sweet Potato Slips

Unlike regular potatoes, sweet potatoes grow from "slips"—shoots produced from mature tubers. Begin this process 4-6 weeks before your last expected frost date:

Select organic sweet potatoes (conventional may be treated to prevent sprouting)
Partially submerge in water using toothpicks, with the pointed end down
Place in warm location (75-80°F) with indirect sunlight
Change water every 2-3 days to prevent stagnation
After 4-6 weeks, when slips are 6-9 inches tall, twist them off
Place slips in water for 1-2 days until roots develop (1/2 inch minimum)

According to the University of Georgia Cooperative Extension, using disease-free planting material reduces crop loss by up to 40% compared to using store-bought tubers that may carry pathogens.

Step 2: Preparing Your Planting Site

Sweet potatoes thrive in loose, well-drained soil. Heavy clay soils cause misshapen tubers and increase rot risk. Amend your soil 2 weeks before planting:

Add 3-4 inches of compost to improve drainage
Mix in 10-15 pounds of well-rotted manure per 100 square feet
Avoid nitrogen-rich fertilizers which promote vines over tubers
Create raised beds 8-10 inches high for better drainage

Sweet potato slips ready for planting in garden

Growth Timeline: What to Expect Week by Week

Weeks After Planting	Plant Development	Care Requirements
1-2	Root establishment, initial vine growth	Water daily if no rain, maintain soil temperature
3-6	Rapid vine expansion, flower buds form	Water 1-1.5 inches weekly, minimal weeding
7-12	Tuber initiation and early bulking	Monitor soil moisture, avoid water stress
13-16	Maximum tuber growth period	Maintain consistent moisture, no late fertilization
17-20	Maturation, leaf yellowing begins	Reduce watering, prepare for harvest

This timeline reflects data from the USDA Agricultural Research Service, which shows tuber bulking accelerates significantly between weeks 10-16 when soil temperatures remain consistently above 70°F.

Step 3: Planting Your Slips Properly

Planting technique dramatically affects yield. Follow these research-backed methods:

Plant after soil reaches 65°F at 4-inch depth (typically 3-4 weeks after last frost)
Dig holes deep enough to cover first 3 leaf nodes
Bend the bottom portion of the slip into an "L" shape before covering
Cover with 2-3 inches of soil, leaving top leaves exposed
Water thoroughly immediately after planting

Research from Clemson University Cooperative Extension shows that planting with the "L" method increases yield by 25% compared to vertical planting, as it encourages more tuber formation along the buried stem section.

Step 4: Ongoing Care for Maximum Yield

Unlike many vegetables, sweet potatoes require specific care practices:

Watering Guidelines

Consistent moisture is crucial during tuber formation (weeks 7-16). Provide 1-1.5 inches of water weekly, but reduce irrigation 3-4 weeks before harvest to improve storage quality. Overwatering during final weeks causes cracked tubers and reduces sweetness.

Weeding Strategy

Weed carefully during first 5-6 weeks using hand tools (avoid cultivators which damage shallow roots). After vines cover the ground, weeds become less problematic. Never hoe after week 6 as you'll damage developing tubers.

Fertilization Approach

Apply balanced fertilizer (5-10-10) at planting time only. Additional nitrogen promotes excessive vine growth at the expense of tubers. If needed, supplement with potassium sulfate 6-8 weeks after planting to support tuber development.

Common Growing Challenges and Solutions

Understanding these context-specific issues prevents crop failure:

Poor tuber formation: Usually caused by excessive nitrogen, cool soil temperatures, or premature harvesting. Solution: Use low-nitrogen fertilizer and wait until leaves begin yellowing.
Cracked tubers: Results from irregular watering during bulking phase. Solution: Maintain consistent soil moisture, especially during weeks 10-16.
Root knot nematodes: Causes bumps on tubers. Solution: Rotate crops every 3 years and plant resistant varieties like 'Covington'.
White mold: Appears as white fungal growth on stems. Solution: Improve air circulation, avoid overhead watering, and remove affected plants immediately.

Harvesting at the Perfect Time

Timing your harvest correctly affects both yield and storage life:

Begin harvesting 90-170 days after planting (varies by cultivar)
Look for yellowing leaves as the primary indicator of maturity
Harvest before soil temperature drops below 50°F
Dig carefully with a digging fork, starting 18 inches from the plant
Allow tubers to dry on the ground for 2-3 hours before handling

According to Oregon State University Extension, harvesting too early reduces yield by up to 50%, while waiting too long risks cold damage that causes internal discoloration.

Proper Curing: The Secret to Sweeter Potatoes

Curing transforms your harvest and is non-negotiable for best results:

Clean excess soil (don't wash)
Store at 85-95°F with 85-90% humidity for 5-7 days
Move to storage conditions: 55-60°F with 75-80% humidity
Allow 3-4 weeks for full flavor development before eating

This curing process converts starches to sugars, dramatically improving sweetness and texture. Uncured sweet potatoes will never develop their characteristic flavor.

Storage Tips for Long-Term Enjoyment

Properly cured sweet potatoes can last 5-6 months when stored correctly:

Use ventilated containers like cardboard boxes with holes
Store in complete darkness (light causes greening)
Maintain temperature between 55-60°F (never refrigerate)
Check monthly and remove any showing signs of decay
Never store near apples or pears which release ethylene gas

Top 3 Sweet Potato Varieties for Home Gardens

Variety	Days to Maturity	Best For	Special Characteristics
'Beauregard'	90-100	All-purpose	Deep orange flesh, high yield, disease resistant
'O'Henry'	100-110	Baking	Creamy white flesh, moist texture, excellent sweetness
'Murasaki'	110-120	Roasting	Purple skin, white flesh, nutty flavor, drought tolerant

These recommendations align with the USDA National Agricultural Library variety trials showing these cultivars consistently outperform others in home garden conditions across multiple climate zones.

Troubleshooting Quick Reference

When problems arise, use this decision tree:

Yellowing leaves: Normal at end of season; premature yellowing indicates water stress or nutrient deficiency
Small tubers: Overcrowding, excessive nitrogen, or early harvest
Hollow centers: Caused by inconsistent watering during bulking phase
Soft spots after storage: Inadequate curing or storage above 60°F

Container Growing Success Tips

Don't have garden space? You can grow sweet potatoes in containers:

Use 15-20 gallon containers with drainage holes
Fill with 60% potting mix, 30% compost, 10% perlite
Plant 1 slip per container
Provide support for vines or let them trail
Water daily during hot weather (containers dry quickly)

Container yields will be smaller but often more consistent, as you control soil conditions completely. Expect 3-5 pounds per container with proper care.

Frequently Asked Questions

Can I grow sweet potatoes from store-bought tubers?

Yes, but only if they're organic. Conventional sweet potatoes are often treated with sprout inhibitors. Organic tubers work well for starting slips, though disease-free seed potatoes from garden suppliers yield more reliable results.

How long does it take for sweet potatoes to grow?

Most varieties require 90-170 frost-free days to reach maturity. Early varieties like 'Beauregard' mature in 90-100 days, while specialty types like 'Japanese' need 140-170 days. The critical factor is warm soil temperature during the bulking phase.

Why are my sweet potatoes stringy?

Stringiness usually results from harvesting too early or growing in overly cool conditions. Sweet potatoes need sufficient time for starches to convert to sugars. Proper curing (85-95°F for 5-7 days) also breaks down fibers. Choose varieties known for smooth texture like 'Covington' for best results.

Do sweet potatoes need full sun?

Yes, sweet potatoes require a minimum of 6-8 hours of direct sunlight daily for optimal growth. Less sun results in smaller yields and less sweet tubers. In extremely hot climates (above 95°F), afternoon shade can prevent soil from overheating, which stresses plants.

Can I plant sweet potatoes in the same spot every year?

No, practice 3-year crop rotation to prevent soil-borne diseases and pest buildup. Sweet potatoes belong to the morning glory family, so avoid planting after other Convolvulaceae plants. Rotate with legumes or brassicas which improve soil conditions for subsequent sweet potato crops.