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Commercial field guide · California

Growing sweet potatoes in California

California has a substantial commercial sweet potato crop. UC guidance places field transplanting from mid-April through the end of June; bed layout, slip supply and the local season determine the field schedule.

California commercial production

Growing for a home garden? See the general sweet potato guide.

Sweet potato field rows prepared for planting

Regional crop context

Sweet potatoes in California

USDA NASS · 2025

USDA NASS reported 18,000 acres planted and 17,900 harvested in California in 2025, producing 5,996,500 cwt. These statewide figures describe the production base, not an individual-field yield forecast.

Harvested area

17,900 acres

Average yield

335 cwt/acre

Total production

5,996,500 cwt

Reported regional totals give production context; they are not a field-level yield estimate.

The California field calendar and bed pattern come from UC ANR’s commercial guide. USDA NASS supplies current state production statistics.

Step 1 of 7 · Assess

Check the field and production system before ordering slips

Set the planting sequence around the production district, irrigation capacity, slip supply, bed preparation and the harvest window. California’s long north–south span makes local temperature readings especially useful.

6 topics still to verify· planning aid only, not a suitability score

Local crop-planning checks

Walk low spots after rain. Confirm the bedder can make stable rows and that water can leave the field.

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Check previous sweet potato, grass or pasture history, nematode results, wireworm pressure and known disease patches.

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Confirm variety, slip quantity, delivery date, setter capacity, water at planting and a plan for keeping slips shaded before setting.

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Match variety and expected root size to the buyer’s fresh-market or processing specification, delivery timing and grading equipment.

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Confirm curing-room volume, airflow, pallet-bin handling and storage space before planting the acreage.

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Map the crop sequence and equipment-cleaning route so infested soil and plant material do not move between fields.

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Need a field-specific review? Run a coordinate-level farm audit for localized conditions.

Read the field history before selecting slips

Root-knot nematodes, wireworms and other soilborne pests affect marketable roots. Soil sampling, clean planting material, crop rotation and equipment sanitation are the first decisions; chemical treatment depends on current field results and product labels.

Step 2 of 7 · Plan

Choose a transplant window in California

UC ANR gives mid-April through the end of June as the California field-transplant period. The cards divide that published span into earlier, central and later planning positions.

Early planting

Mid-April–early May

The early portion of UC ANR’s field window. Confirm warm soil at planting depth and dependable slip supply.

Main planting

May–early June

The central portion of the published California transplant period; coordinate the planting sequence with bed preparation and irrigation.

Late planting

Mid–late June

The end of UC ANR’s stated field window. Match variety maturity and harvest capacity to the remaining warm season.

Early plantingMain plantingLate planting

Historical regional climate

Monthly soil and air temperature context

1996-01-01 to 2025-12-31

Green tiles are months whose mean soil temperature is in the 77–86°F root-development range; all other tiles are neutral and show the value. Early, main and late badges mark the 10th, median and 90th-percentile dates for reaching 18.3°C for 4 consecutive days. Bar height shows the mean.

Early soil-warming date

March 24

10th percentile

Median soil-warming date

April 23

median year

Late soil-warming date

May 05

90th percentile

  • Early · 10th percentile
  • Main · median
  • Late · 90th percentile
  • 77–86°F root range
  • Cooler or warmer than the root range

June: regional monthly means

Modeled soil temperature
28.9°C · 0–7 cm model layer
Mean air temperature
26.1°C

Months whose historical mean soil temperature reaches the 65°F reference: May, June, July, August, September, October. Months in the 77–86°F root-development range: June, September. These are monthly regional averages, not planting dates or a frost check.

Open-Meteo · era5_land · 1996-01-01 to 2025-12-31 · Reference point 37.00°N, 120.00°W. Soil-temperature values are modeled at 0–7 cm model layer; the 65°F (18.3°C) transplant reference comes from a 4-inch field measurement. Use the regional calendar above with a current field reading.

Set the field date from a real soil reading

Sweet potato slips establish best after frost risk has passed and the soil is at least 65°F (18.3°C) at 4 inches. That is a field measurement; the climate strip above shows regional history.

Match the date to variety maturity

Use the regional crop duration and expected fall cutoff to choose a variety and harvest date. Confirm market grade, digging capacity and curing space before planting.

Step 3 of 7 · Prepare

Build an aerated bed and keep the crop sequence clean

California production uses shaped beds and irrigated fields. Match bed preparation to the production district’s soil texture, irrigation system and harvest equipment.

The bed does several jobs

  • Improves aeration and drainage around developing roots.
  • Warms the crop zone for a warm-season transplant.
  • Gives the setter and digger a consistent row to follow.

Keep bed height and shape consistent with soil texture, water movement and the equipment used on the farm.

Cross-section of a crowned sweet potato bed with arrows showing surface runoff moving down the shoulders.
A crowned, loose bed gives developing roots an aerated zone and can shed surface water down its shoulders. Shape the row for field soil, drainage and equipment; schematic, not to scale.

Set fertility from the field test

Base pH and fertilizer rates on representative soil tests. Avoid excess nitrogen, which can favor vine growth over marketable storage-root sizing.

Step 4 of 7 · Establish

Plant slips, not seed, and calculate the stand

Sweet potatoes are established from vegetative vine cuttings called slips. Buy clean, healthy slips in the target variety and quantity, and keep them shaded and moist until planting.

Sweet potato slip set diagonally with its shoot and leaves above the soil, at least three buried nodes, new roots and a 3–4 inch depth mark.
Set the slip so at least three nodes sit below the soil while the growing tip and leaves remain above. The 3–4 inch (7.6–10.2 cm) depth is a practical guide; node position is the key. Leaf shape varies by cultivar. Water after transplanting.

Regional starting pattern

Bed centers
80 in (203 cm) bed centers · 2 rows per bed
Between slips
9–15 in (23–38 cm)
Transplant depth
3–4 in (7.6–10.2 cm), with at least three nodes covered

UC ANR’s California layout uses two planted rows on 80-inch beds, with 9–15 inches between slips. The calculator counts both rows on each bed.

Planting calculator

Estimate slips for your field

Spacing-based count

Estimated slips

13,068

at 80 × 12 in

Estimate = field area ÷ row-by-slip spacing, multiplied by 2 rows per bed. Keep values within the published bounds, then match the starting pattern to equipment and target root grade. Headlands and replant allowance are not included.

Step 5 of 7 · Manage

Protect the establishment period and the root grade

The first weeks determine how evenly slips establish and how the crop competes. Protect the crop from early weed competition and scout for wireworms, flea beetles and root-knot nematodes. Use field history, clean planting material and equipment sanitation to reduce avoidable risk.

Get water onto the slip at planting

Water immediately after setting and maintain enough moisture for root establishment. Track rainfall and soil moisture; avoid keeping beds saturated.

Keep the field clean while the crop closes rows

Scout early and maintain a weed-free start through canopy closure. Choose current control methods for the farm’s production system.

Scout below the canopy as well

Wireworms, flea beetles and root-knot nematodes can downgrade roots. Keep field history and scouting records tied to each harvest lot.

Keep tools and planting stock clean

Use certified or otherwise clean slips, avoid carrying soil on slips, and clean equipment after infested fields to limit movement of nematodes and soilborne disease.

Step 6 of 7 · Harvest

Dig at the planned size, cure quickly and protect the skin

UC ANR describes California harvest and marketing practices for commercial growers. Schedule digging and curing with the target district, variety and delivery plan.

A tractor lifting sweet potatoes during field harvest
At harvest, protect the skin and move roots promptly to curing; equipment and handling systems vary by region.

Harvest period

Schedule from the planting date, variety cycle and local harvest plan.

Plan by variety, market size, planting date, field condition and frost risk.

Cure

80–85°F · 85–90% RH

A crop-level curing reference is 7–10 days with airflow; use the facility and buyer protocol for the harvested lot.

Store

55–60°F · about 85% RH

Maintain stable temperature, humidity and ventilation after curing.

Step 7 of 7 · Reference

Evidence behind the California guide

View references (5)
  1. 1. UC ANR — Sweetpotato Production in California, ANR 7237Publication date 1998; commercial guide

    California field-transplant period, two-row 80-inch beds, in-row spacing, production, harvest and marketing practices.

  2. 2. USDA NASS — Vegetables 2025 SummaryPublished 12 February 2026

    2025 California planted and harvested area, average yield and total production.

  3. 3. Washington State University Extension — Sweetpotato Production PracticesPublished January 2026

    Crop-level soil-temperature context, bed preparation, equipment-led row spacing and the relationship between plant density and root size.

  4. 4. University of Missouri Extension — Growing Sweet PotatoesReviewed March 2026; originally published September 2017

    Crop-level transplant establishment, slips, frost sensitivity and raised-bed practice. Missouri calendar dates are not applied to other regions.

  5. 5. Texas A&M AgriLife — Sweet Potato commercial crop profileOlder technical profile; undated PDF

    Shared crop-level reference for curing and storage conditions. Its Texas planting calendar is used only on the Texas page.

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