When to Plant Sweet Potatoes in Maryland
Published: April 24, 2026
Maryland gardeners in Zone 6a have a 31-week growing season for sweet potato (March 30 to November 1). The moderate climate supports a full warm-season crop plus a single main harvest. This guide gives exact dates for Maryland based on your local frost calendar.
Sweet Potato Planting Dates for Maryland
| Start seeds indoors | Year-round |
| Last frost (average) | March 30 |
| Direct sow outdoors | April 20–30 |
| Expect first harvest | July 19 – August 18 |
| First fall frost (average) | November 1 |
Dates above assume Zone 6a, the most common zone in Maryland. Gardeners in cooler Baltimore (Zone 6a) plant 1–2 weeks later; warmer Waldorf (Zone 6b) can plant 1–2 weeks earlier.
⚠ Plant sweet potato slips 2–3 weeks after last frost when soil is consistently above 60°F. Needs 90–120 days of warm weather. Best in Zones 5–11.
Growing Sweet Potatoes in Maryland's Climate
Maryland's moderate Zone 6a climate is well-suited to sweet potato with minimal special accommodation. The standard transplant calendar works as written, and harvest windows line up with what seed packets recommend without adjustment.
Succession planting extends your sweet potato harvest significantly in Maryland. A second planting 3 to 4 weeks after the first gives you a backup in case of pest pressure and extends the total harvest window into early fall.
Common sweet potato pests to watch for in Maryland include Sweet Potato Weevil and Wireworm. The first line of defense is companion planting: Bush Bean and Pea planted nearby discourage several of these pests by confusing host-plant identification or repelling adults before they can lay eggs. Weekly garden walks in the early morning catch problems when they're still manageable.
Sweet Potato Garden Calendar for Maryland
| Month | Task | Notes |
|---|---|---|
| January | — | Dormant season |
| February | — | Dormant season |
| March | — | Dormant season |
| April | Direct sow seeds | Sow seeds 1/4–1/2 inch deep, 12 inches apart |
| May ← | — | Dormant season |
| June | Peak growth; water 1 inch/week | Monitor for pests daily; stake or support as needed |
| July | Continue care | Consistent watering; remove yellow leaves |
| August | — | Dormant season |
| September | — | Dormant season |
| October | — | Dormant season |
| November | First frost approaches | Harvest remaining sweet potato; cover plants on frost nights |
| December | — | Dormant season |
Sweet Potato Growing Tips for Maryland Gardeners
- •Order slips in early spring from a seed company; plant within 24 hours of arrival in pre-warmed soil.
- •Form raised ridges or mounds 10 inches tall — sweet potatoes size up best in loose, warm, well-drained soil.
- •Maryland's moderate climate supports succession planting — sow new transplants or seeds every 3 weeks during spring to extend the harvest window into fall.
- •Black plastic mulch warms soil quickly in northern climates and can add 2 weeks to the effective growing season.
Companion Planting for Sweet Potatoes in Maryland
In Maryland's moderate climate, planting sweet potato with Bush Bean and Pea helps deter pests and improve soil. Avoid planting near Squash and Tomato, which inhibit sweet potato growth through root chemistry or shared pest pressure. See the full sweet potato companion planting guide for the complete list.
Sweet Potatoes Planting Dates by City in Maryland
Top cities in Maryland — select for city-level frost dates and planting calendars.
Frequently Asked Questions
When should I plant sweet potato in Maryland?
In Maryland (Zone 6a), start sweet potato seeds indoors around Year-round and transplant outdoors around null — 3 weeks after the state's average last frost of March 30.
What is the last frost date in Maryland?
Maryland's average last frost date is March 30 in the state's most common Zone 6a. Frost dates vary by city — higher elevations and northern counties run 1 to 3 weeks later than the state average. See the city list below for city-level frost dates.
Can I grow sweet potato year-round in Maryland?
Not year-round — Maryland's cold season stops sweet potato production. The sweet potato season runs March 30 to November 1, roughly 31 weeks.
What sweet potato varieties grow best in Maryland?
For Maryland's Zone 6a, consult a local nursery or extension office for sweet-potatoes variety recommendations.
When do I start sweet potato seeds indoors in Maryland?
Sweet potato does not need indoor starting in Maryland — direct sow around April 20–30 once soil reaches 60°F. Indoor starting is not recommended for this crop because sweet potato transplants poorly.