Curing Schedule & Seal It for Long Storage
Cures potato
Pick the crop and enter your curing temperature, humidity and days to read the recommended curing temp / RH / duration, the storage conditions to transition to, the expected weight loss, and a too-cold / too-humid / too-dry flag — live as you type.
Curing plan
Next: cure then transition. Hold Potato at 15°C · 95% RH for 12 days (suberization + wound-periderm formation seals cuts and bruises.), expect about 0.28% weight loss, then cool to the storage set-point of 4°C · 95% RH for roughly 8 months of life.
Curing seals harvest wounds and sets dormancy before storage — potato/sweet-potato suberize (warm + very humid), onion/garlic dry their necks (warm + drier), squash hardens its skin. Weight loss is transpiration, driven by the air's vapour-pressure deficit (VPD = saturation × (1 − RH/100)); higher temperature or lower RH = faster loss. Sources: USDA Agriculture Handbook 66; UC-Davis / NC State / Cornell postharvest curing guides. Conditions are recommended ranges; verify with your own airflow and crop maturity.
Curing — key facts
- Potato cure
- 10–15°C, ~95% RH, 10–14 d
- Sweet potato cure
- 29–32°C, 85–90% RH, 4–7 d
- Onion cure
- 28–35°C, 65–75% RH, ~10 d
- Garlic cure
- 27–35°C, 60–70% RH, 2–4 wk
- Weight loss
- loss ≈ base × (VPD ÷ ref VPD) × days
- Potato storage
- ≈ 4°C, 95% RH
- Onion storage
- ≈ 0°C, 65–70% RH
- Chilling-sensitive
- sweet potato, pumpkin, yam, cassava
- Failure flags
- too cold · too humid · too dry
- Privacy
- Runs in your browser; nothing uploaded
Curing schedules and storage conditions by crop
Each crop cures at its own temperature, humidity and duration, then transitions to a different long-term storage set-point. These reference values drive the schedule, the weight-loss estimate and the failure flag.
| Crop | Cure temp (°C) | Cure RH (%) | Cure days | Store temp (°C) | Store RH (%) | Storage life (mo) | Notes |
|---|---|---|---|---|---|---|---|
| Potato | 15 | 95 | 12 | 4 | 95 | 8 | Cure 10–15°C, ~95% RH, 10–14 d; then cool to 4°C (table) / 8–10°C (processing) to limit sugars. |
| Sweet potato | 29 | 90 | 6 | 13 | 88 | 7 | Cure 29–32°C, 85–90% RH, 4–7 d; store 13–15°C — chilling injury below 12°C. |
| Onion | 30 | 70 | 10 | 0 | 68 | 7 | Field- or heat-cure 28–35°C, 65–75% RH until necks tight; store 0°C, 65–70% RH. |
| Garlic | 30 | 65 | 14 | 0 | 65 | 7 | Cure 27–35°C, 60–70% RH, 2–4 weeks; store 0°C or warm 27°C (avoid 4–18°C sprout zone). |
| Pumpkin / winter squash | 27 | 80 | 10 | 13 | 60 | 4 | Cure 27°C, 80% RH, 10 d; store 12–15°C, 50–70% RH — chilling injury below 10°C. |
| Yam (Dioscorea) | 32 | 90 | 5 | 15 | 70 | 5 | Cure 29–32°C, 90–95% RH, 4–8 d; store 15–16°C — chilling-sensitive. |
| Cassava | 30 | 90 | 5 | 5 | 85 | 1 | Cure 30–40°C, high RH, 4–7 d; deteriorates within days uncured. |
Sources: USDA Agriculture Handbook 66, "The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks"; extension curing guides (UC-Davis, NC State sweet potato, Cornell onion/potato). Conditions are recommended ranges; field results vary with airflow and maturity.
Curing seals the crop before it goes to store
A freshly harvested tuber or bulb is covered in tiny cuts, bruises and an undried neck — every one of them an open door for decay. Curing closes those doors. In potatoes and sweet potatoes, warm humid air drives suberization and wound-periderm formation, sealing the surfaces; in onions and garlic, warm drier air drives neck-drying so the bulb seals and dormancy holds; in pumpkin and squash, the skin hardens. Skip curing, or do it in the wrong air, and the crop simply will not keep.
This tool gives the curing temperature, humidity and duration for your crop, then the cooler storage set-point to transition to afterward, and estimates the weight you will lose to transpiration along the way — driven by the vapour-pressure deficit of your curing air. If your conditions stray too cold, too humid or too dry, it flags exactly which way to correct them, so the crop seals properly and earns its months of storage life.
How to use it in five steps
- 1Pick the crop
Select potato, sweet potato, onion, garlic, pumpkin, yam or cassava — the tool loads its curing and storage conditions.
- 2Enter your curing air
Enter the temperature and relative humidity you can actually hold in the curing space.
- 3Enter the curing days
Enter how many days you plan to cure before moving the crop to long-term storage.
- 4Read the schedule and loss
Read the recommended temp/RH/duration, the expected curing weight loss, and the storage set-point to transition to.
- 5Correct any flag
If it flags too cold, too humid or too dry, nudge the air toward the recommended band, then re-check.
Frequently Asked Questions
What is curing and why does produce need it?+
Curing is a controlled wound-healing and drying step before long-term storage. For potato and sweet potato it drives suberization and wound-periderm formation so cut and bruised surfaces seal against rot; for onion and garlic it dries the neck and outer scales so the bulb seals and dormancy holds; for pumpkin and winter squash it hardens the skin. Without curing, wounds stay open, decay organisms get in, and the crop will not hold in storage.
How long should I cure potatoes before storage?+
Cure potatoes at 10–15°C and about 95% relative humidity for roughly 10–14 days to suberize the skin and heal wounds, then cool down to the storage set-point — around 4°C for table potatoes or 8–10°C for processing potatoes to limit sugar build-up. The calculator returns the recommended duration for your entered conditions and flags the transition to cold storage.
What temperature and humidity cure onions?+
Onions are field- or heat-cured at 28–35°C and 65–75% relative humidity — drier air than tubers — until the necks are tight and the outer scales are papery, typically around 10 days. They are then stored cold and dry, near 0°C at 65–70% RH. Onions cured in air that is too humid will not dry their necks and are prone to neck rot, which the tool flags as too-humid.
How do I cure sweet potatoes?+
Sweet potatoes need high heat and high humidity: cure at 29–32°C and 85–90% RH for 4–7 days to heal wounds and set the skin, then store at 13–15°C. They are chilling-sensitive and suffer injury below about 12°C, so they must not go into cold storage like potatoes. Curing too cold (below ~27°C) means the wounds will not seal.
How long does garlic take to cure?+
Garlic cures slowly — roughly 2 to 4 weeks (about 14 days as a planning figure) at 27–35°C and 60–70% RH while the neck and wrapper leaves dry and the bulbs seal. Store cured garlic either cold near 0°C or warm around 27°C, and avoid the 4–18°C range, which is the sprouting zone. The tool shows both the curing schedule and the recommended storage set-point.
Why does the calculator estimate weight loss?+
Some moisture loss during curing is normal and necessary — it is how the surfaces dry and seal — but excess loss is shrinkage you cannot sell. Weight loss during curing is dominated by transpiration, which is driven by the vapour-pressure deficit (VPD) of the curing air: the drier the air relative to the produce surface, the faster the loss. The tool scales a per-crop base loss rate by your air's VPD relative to a reference and integrates it over your curing days.
How does humidity affect curing weight loss?+
Lower humidity at a given temperature raises the vapour-pressure deficit, so the produce transpires faster and loses more weight per day. That is why onions and garlic, cured in drier air, lose more weight than potatoes cured at 95% RH. The relationship is roughly linear in VPD: daily loss ≈ base rate × (air VPD ÷ reference VPD), accumulated over the cure period.
What happens if I cure too cold?+
If the curing temperature is below the crop's minimum, the wound-healing and drying processes slow or stall: potato and sweet potato wounds do not suberize, onion and garlic necks do not dry, and dormancy is not set. The crop goes into storage with open wounds and wet necks and decays. The tool flags this as a too-cold failure and shows the minimum curing temperature for the crop.
What happens if curing is too humid or too dry?+
Too humid — especially for onion and garlic — means the necks and scales never dry, so the bulbs do not seal and neck rot sets in; the tool flags this as too-humid. Too dry means the produce over-transpires and can shrivel or scald, losing saleable weight; the tool flags this as too-dry. The aim is the crop's recommended RH band, which seals the surface without excessive shrinkage.
Do I cure and store at the same conditions?+
No — curing and storage are two different set-points. Curing is warm (and humid for tubers, drier for bulbs) to heal and seal; storage is then cooler to slow respiration, sprouting and decay. Potatoes go from 10–15°C curing to 4°C storage; sweet potatoes from 29–32°C curing to 13–15°C storage; onions from 28–35°C curing to near 0°C storage. The tool shows both, plus the expected storage life.
Which crops are chilling-sensitive and must not be stored cold?+
Sweet potato (injury below ~12°C), pumpkin and winter squash (injury below ~10°C), yam (chilling-sensitive, stored 15–16°C) and cassava all suffer chilling injury and must be stored warm, unlike potato, onion and garlic which store cold. Storing a chilling-sensitive crop too cold causes pitting, off-flavours and decay even though the temperature seems safe.
Is my curing duration long enough?+
The tool compares your planned curing days against the crop's recommended duration and flags if you are short. Curing too briefly leaves wounds unsealed and necks undried, so the crop enters storage vulnerable. As a rule, do not shorten curing to save time on a high-value storage crop — a few extra days of curing buys months of storage life.
What is the formula for curing weight loss?+
Daily loss (%) ≈ base loss rate × (curing-air VPD ÷ reference VPD), where VPD = saturation vapour pressure at the curing temperature × (1 − RH/100), and total loss = daily loss × curing days. Saturation vapour pressure is estimated with the Magnus–Tetens approximation. The base rate is per-crop and the reference VPD represents a typical warm, moderately humid curing environment.
Is anything uploaded?+
No. The calculation runs entirely in your browser using the built-in crop curing table and the VPD weight-loss model. Nothing you enter is sent anywhere.