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Postharvest handling of fruit and vegetable crops in Minnesota

Pumpkins curing before storage

Proper postharvest handling of fresh market fruits and vegetables will allow you to sell high-quality products and extend the shelf life of your produce.

Produce is at its highest quality at harvest, so culling diseased or injured produce (toss or sell them first) and storing only the highest quality product is recommended.

The tasks listed below will help you maintain the postharvest quality of your farm produce.

Removing field heat

The faster you get produce to the correct storage temperature, the longer it will last. You can help produce get to the appropriate storage temperature by removing the heat held by the product when it was growing in the field.

Harvest early in the morning, before the hottest part of the day, so that your produce starts out relatively cool. The following three methods can be used to remove field heat from fruits and vegetables.

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Curing

  • Most fruits and vegetables do not need to be cured before storing, but a few do, including onions, garlic, pumpkins, winter squash, potatoes and sweet potatoes.
  • Curing heals wounded areas on the surface of fruit or tubers. It also helps the necks and outer skins of garlic and onions dry before long-term storage.
  • Proper curing helps to prevent plant pathogens from spreading in storage and extends the shelf-life of fruits and vegetables. 
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Rinsing produce

  • Some produce should be washed after harvest to remove soil and debris, but this is not necessary for all crops.
  • The shelf life of some products, like fresh herbs, berries and tomatoes will be severely limited if they are rinsed.
  • Crops like green beans, eggplant, peppers and squash may need a rinse only if they are dirty or dusty.
  • Depending on the rain and if there is plastic or other mulch below the plants, crops may not need any rinsing.
  • Other crops can be wiped with single-use towels or clean gloves, or dry brushed.
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Sorting

All crops going into storage should be sorted to prevent diseased plant material from entering your storage facility. A single diseased onion or potato can result in a pathogen spreading throughout an entire bin. Throughout the harvest, curing, and washing processes, check for plants with soft tissue, spots, bruises, or cuts, and remove them. After putting produce in storage, periodically check the product and cull items that are diseased.

Sorting recommendations for major fruit crops:

Grapes

  • Grapes for wine should be sorted based on cluster quality.
  • A small amount of injured fruit may be admissible, depending on the winery’s preferences.
  • For table grapes, damaged berries should be removed prior to sale.
  • Refer to these resources for more information: What to do with bad grape clusters.

Apples

Strawberries

  • Cull any berries with wounds such as insect bites, rotting, or soft spots.
  • Since strawberries are soft fruits, wounds on the berries can cause them to degrade quickly.
  • Berries with deformities from tarnished plant bugs or frost are not marketable as first-grade fruit, but are still edible and may be used for processing.

If diseased produce is added to a cull pile, proper composting may reduce the presence of pathogens before applying compost generated from cull piles back to fields.

Unfinished compost may harbor plant pathogens and can tie up nitrogen in the soil while it decomposes.

An alternative is to keep a cull pile for diseased plants in an area far away from your production fields and to avoid adding any compost generated from that site back to production areas.

According to the National Organic Program standards, compost temperatures must remain between 131ºF and 170ºF for 15 days, while being turned a minimum of 5 times. Compost takes much longer than 15 days to fully break down, but these 15 days of high heat and aeration help to reduce plant pathogen pressure.

Read more about the full protocols for composting in accordance with the NOP guidelines. 

Crop-specific recommendations and shelf-life

Commodity Washing procedure How to remove field heat Optimal storage conditions Expected shelf life*
Apples Wash Water 32 - 40 F, 95% RH 2-6 months, depending on variety
Asparagus - Air or water 32 F, 95% RH 2-3 weeks
Basil - Air 55 F, 95% RH 2 weeks
Beans Wash Air or water 45 - 50 F, 95% RH 1 -1.5 weeks
Beets Wash Air, water, or ice 32 F, 95% RH 8+ months
Blueberries - Air 32 F, 95% RH 2 weeks
Broccoli - Water or ice 32 F, 95% RH 2-3 weeks
Brussels sprouts Wash Water or ice 32 F, 95% RH 3-5 weeks
Cabbage Wash Water or ice 32 F, 95% RH 1 month
Cantaloupe Brush or wipe Air 40 F, 95% RH 2 weeks
Carrots Wash Water 32 F, 95% RH months
Cauliflower - Water or ice 32 F, 95% RH 3 weeks
Cucumbers Wash, brush or wipe Air 50 F, 95% RH 2 weeks
Currants - Air 32 F, 95% RH 2-3 weeks
Eggplant Wash, brush or wipe Air 50 F, 95% RH 2 weeks
Garlic Rub dry scales 40 F, 60% RH 9 months
Herbs (fresh - not basil) Air 32 F, 95% RH 1-4 weeks
Honeydew melon Brush or wipe Air 45 - 50 F, 95% RH 1 week
Leafy greens Wash Water or ice 32 F, 95% RH 2 weeks
Leeks Wash Water or ice 32 F, 95% RH 2-3 months
Okra - Air 45 F, 95% RH 1-2 weeks
Onions - 40 F, 50% RH 6-9 months
Parsnips Wash Water or ice 32 F, 95% RH 4-6 months
Peas - Water or ice 32 F, 95% RH 1-2 weeks
Peppers Air 45 F, 95% RH 2-3 weeks
Potatoes Wash after storage 40 - 50 F, 95% RH up tp 12 months, depending on variety
Pumpkins Brush or wipe Air 50 F, 50% RH 2-3 months
Radishes Wash Water or ice 32 F, 95% RH 3-4 weeks tops removed, 1-2 weeks with tops
Raspberries - Air 32 F, 95% RH 2-5 days
Rhubarb - Air or water 32 F, 95% RH 2-4 weeks
Rutabaga Wash Water or ice 32 F, 95% RH 4-6 months
Spinach Wash Water or ice 32 F, 95% RH 2 weeks
Strawberries - Air 32 F, 95% RH 1 week
Summer squash Wash Air or water 40 F, 95% RH 2 weeks
Sweet Corn - Water or ice 32 F, 95% RH 2 weeks
Sweet Potatoes Wash 60 F, 95% RH up to 12 months
Tomatoes Wash, brush or wipe Air 50 F, 95% RH days
Turnips Wash Water or ice 32 F, 95% RH 4-5 months
Watermelon Brush or wipe 50 - 60 F, 95% RH 2-3 weeks
Winter squash - acorn Brush or wipe Air 50 F, 50% RH 1 month
Winter squash - hubbard Brush or wipe Air 51 F, 50% RH 6 months
Winter squash - buttercup Brush or wipe Air 52 F, 50% RH 3 months
Winter squash - butternut Brush or wipe Air 53 F, 50% RH 2-3 months
Winter squash - kuri Brush or wipe Air 54 F, 50% RH 4-5 months

*Shelf life reported for ideal conditions; actual shelf life may be reduced.

Authors: Cindy Tong, Natalie Hoidal, Annalisa Hultberg and Annie Klodd, Extension educators

Reviewed in 2024

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