Żyznów · southeast Poland
A three-year field experiment recorded mid-May transplanting, mid-October harvest and tests of frost-protection covers.
Planting reference: 13–16 May · 2021–2023 field trials
View local climate and growing guideRegional field-trial overview · Poland
Sweet-potato trials in Żyznów show what the crop can do in southeast Poland. The linked guide compares the actual May trial dates with climate data for the study location rather than the central-Poland reference point.
Żyznów · southeast Poland trial site
Growing for a home garden? See the general sweet potato guide.

Regional crop context
Three field seasons at Żyznów tested transplanting, ridges and frost protection. The research demonstrates local trial potential; it does not establish national commercial output.
Dates, layout and results are from the Żyznów experimental site; they are not a national commercial calendar.
Step 1 of 7 · Assess
Use the Żyznów study as the local trial reference: plan frost protection, ridge setup, slip supply and a mid-October harvest window before choosing acreage.
6 topics still to verify· planning aid only, not a suitability score
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Need a field-specific review? Run a coordinate-level farm audit for localized conditions.
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
Open the Żyznów guide for the exact 2021–2023 trial dates and local climate profile.
A three-year field experiment recorded mid-May transplanting, mid-October harvest and tests of frost-protection covers.
Planting reference: 13–16 May · 2021–2023 field trials
View local climate and growing guideStep 3 of 7 · Prepare
The southeast Poland experiments used ridges and tested polyethylene and polypropylene covers to manage low temperatures. Adapt bed preparation to drainage and machinery.
Keep bed height and shape consistent with soil texture, water movement and the equipment used on the farm.

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
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.

The 2021–2023 Żyznów trial reports a 75 × 40 cm row-by-plant pattern on ridges. The calculator bounds changes within a published European field-trial envelope.
Planting calculator
Estimated slips
33,333
at 75 × 40 cm
Estimate = field area ÷ row-by-slip spacing. 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
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.
Water immediately after setting and maintain enough moisture for root establishment. Track rainfall and soil moisture; avoid keeping beds saturated.
Scout early and maintain a weed-free start through canopy closure. Choose current control methods for the farm’s production system.
Wireworms, flea beetles and root-knot nematodes can downgrade roots. Keep field history and scouting records tied to each harvest lot.
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
The Żyznów study harvested in mid-October and tested covers because late spring and early autumn frost can constrain the crop.

Harvest period
Plan by variety, market size, planting date, field condition and frost risk.
Cure
A crop-level curing reference is 7–10 days with airflow; use the facility and buyer protocol for the harvested lot.
Store
Maintain stable temperature, humidity and ventilation after curing.
Step 7 of 7 · Reference
Żyznów transplant dates, ridge spacing, mid-October harvest and frost-cover trials.
Earlier southeast Poland field experiments on covers and within-row spacing.
European field trial comparing 80 × 20, 80 × 30, 100 × 20 and 100 × 30 cm row-by-plant spacing. Used as a crop-level spacing reference, not a local calendar.
Crop-level soil-temperature context, bed preparation, equipment-led row spacing and the relationship between plant density and root size.
Crop-level transplant establishment, slips, frost sensitivity and raised-bed practice. Missouri calendar dates are not applied to other regions.
Shared crop-level reference for curing and storage conditions. Its Texas planting calendar is used only on the Texas page.
Photo authorship and licence information are recorded centrally. View photo credits.