How to Plant Sweet Potatoes: Soil Prep, Spacing, and Transplanting Slips

Planting sweet potatoes the right way sets the foundation for a big harvest. After years of growing them in my warm Sonoma Valley garden—where loose soil, careful spacing, and healthy slips make all the difference—I’ve learned that the planting stage determines 90% of your success. Sweet potatoes are simple plants, but they respond dramatically to how you prepare the bed and position each slip.

Here’s my experience-based guide to planting sweet potatoes with confidence.

Table of Contents

Prepare Loose, Warm, Compost-Rich Soil

Sweet potatoes thrive in soil they can stretch through easily. Their long storage roots need space and softness to grow straight and full.

What Sweet Potatoes Want:

Loose, well-drained soil—sandy loam is ideal
Warm soil, at least 70°F (21°C)
Plenty of organic matter, but not too much nitrogen
pH between 5.5 and 6.5

My Sonoma Method:

I always add 2–3 inches of compost and turn it into the top 8–10 inches of soil. Compost adds structure and warmth without overfeeding. In raised beds, this creates near-perfect conditions for smooth, well-shaped tubers.

Tip from experience:
If your soil is heavy or compacted, mount a 6–8 inch high ridge. My best crops have always come from slightly elevated rows—they warm faster and drain better.

Give Sweet Potatoes Plenty of Room to Run

Spacing matters more than most gardeners realize. Too close, and the vines tangle and the tubers become small or misshapen. Sweet potatoes need both vertical rooting space and horizontal room for vines.

Recommended Spacing:

12–18 inches between slips
36 inches between rows

This allows for a full canopy of vines without shading or crowding.

My experience:
When I space slips at 16–18 inches, I consistently get the longest, smoothest roots. Tight spacing always leads to smaller yields.

Plant Slips Deep for Strong Root Systems

Sweet potato slips form roots all along the buried stem. Planting them deeply creates a sturdier plant and a more productive root zone.

How to Plant:

Dig a hole 4–6 inches deep.
Strip the lower leaves from the slip.
Bury 2–3 inches of the stem (or lay the slip sideways and bury the lower half horizontally).
Firm the soil gently around the slip.
Water deeply to settle the soil.

My Sonoma tip:

When the soil is very warm, deeply buried slips root immediately and never stall. When soil is borderline warm, burying them slightly less helps prevent rot.

Water Well at Planting—Then Ease Off

Newly set slips need steady moisture to establish.

Watering Schedule:

Week 1–4: Keep soil consistently moist.
After establishment: Water once or twice per week depending on heat.
Final 3 weeks before harvest: Reduce watering to improve sweetness and prevent cracking.

In my garden:
A single drip line down the row gives perfect moisture without overwatering. Too much water early can cause slips to rot—steady, not soggy, is the goal.

Protect Young Slips if Nights Are Cool

Sweet potatoes thrive in warmth, and cool nights can slow or stunt early growth.

Protection options:

Lightweight row cover
A temporary low tunnel
Planting near a warm south-facing wall

I often cover slips during their first week outdoors if nights dip below 55°F. This small step has saved more than one early planting for me.

Final Thought

Planting sweet potatoes well means giving slips warm, loose soil; generous spacing; and the right depth for strong rooting. In my Sonoma garden, these steps have produced consistently large, sweet, long-storing tubers year after year. Once slips take off, sweet potatoes need little from you—so the time you invest at planting pays back all season long.