When harvesting vegetables, be careful not to break, nick, or bruise them. The less vegetables are handled, the longer they will last in storage. Harvest only vegetables of high quality. Rotting produce cannot be stored for very long, and could spread disease to other stored vegetables.
Different vegetables need different storage conditions. Temperature and humidity are the main storage factors to consider; there are three combinations for long-term storage:
1. Cool and dry (50-60°F and 60% relative humidity)
2. Cold and dry (32-40°F and 65% relative humidity)
3. Cold and moist (32-40°F and 95% relative humidity)
For cold conditions, 32°F is the optimal temperature, but it isn’t easy to attain in most homes. Expect shortened shelf-lives for your vegetables as storage conditions deviate from the optimal, as much as 25% for every 10°F increase in temperature. Some vegetables, such as cucumbers, peppers, and tomatoes, require cool (55°F) and moist storage. These conditions are difficult to maintain in a typical home, so expect to keep vegetables requiring cool and moist storage conditions for only a short period of time.
Where can the different storage conditions be found in a typical home? Basements are generally cool and dry. If storing vegetables in basements, provide your vegetables with some ventilation. Harvested vegetables are not dead, but still “breathe” and require oxygen to maintain their high quality. Also, be sure they are protected from rodents.
Home refrigerators are generally cold and dry (40°F and 50-60% relative humidity). This is fine for long-term storage of garlic and onions, but not much else. Putting vegetables in perforated plastic bags in the refrigerator will provide cold and moist conditions, but only for a moderate amount of time. Unperforated plastic bags often create too humid conditions that lead to condensation and growth of mold or bacteria.
Root cellars provide cold and moist conditions. As with basements, provide ventilation and protection from rodents when storing vegetables in cellars. Materials such as straw, hay, or wood shavings can be used as an insulation. If using such insulation, make sure it is clean and not contaminated with pesticides.
Specific harvest and storage information for some commonly-grown vegetables is below. Expected shelf-life times are only estimates.
When to Harvest
How to Store
|Asparagus||3rd year after planting when spears are 6-9 inches long||Cold and moist||2 weeks||Keep upright|
|Basil||When leaves are still tender||At room temperature||5 days||Keep stems in water; will discolor if kept in refrigerator for 10 days|
|Beans, snap||About 2-3 weeks after bloom when seeds still immature||Cold and moist||1 week||Develop pitting if stored below 40°|
|Beets||When 1.25-3 inches in diameter||Cold and moist||5 months||Store without tops|
|Broccoli||While flower buds still tight and green||Cold and moist||2 weeks|
|Brussel sprouts||When head’s 1 inch in diameter||Cold and moist||1 month|
|Cabbage||When head is compact and firm||Cold and moist||5 months|
|Carrots||When tops 1 inch in diameter||Cold and moist||8 months||Store without tops|
|Cauliflower||While head is still white, before curds “ricey”||Cold and moist||3 weeks|
|Corn, sweet||When silks dry and brown, kernels should be milky when cut with a thumbnail||Cold and moist||5 days|
|Cucumbers||For slicing, when 6 inches long||Cool spot in kitchen 55°F in perforated plastic bags; storage in refrigerator for a few days okay||1 week||Develops pitting and water-soaked areas if chilled below 40°F; do not store with apples or tomatoes|
|Eggplant||Before color dulls||Like cucumbers||1 week||Develops pitting, bronzing, pulp browning if stored for long period below 50°F|
|Kohlrabi||When 2-3 inches in diameter||Cold and moist||2 months||Store without tops|
|Lettuce||While leaves are tender||Cold and moist||1 week|
|Muskmelons (cantaloupe)||When fruits slip off vine easily, while netting even, fruit firm||Cold and moist||1 week||Develops pitting surface decay with slight freezing|
|Onions||When necks are tight, scales dry||Cold and dry||4 months||Cure at room temperature 2-4 weeks before storage, don’t freeze|
|Parsnips||When roots reach desired size, possibly after light frost||Cold and moist||4 months||Do not wax or allow roots to freeze; sweetens after 2 weeks at 32°F|
|Peas||When pods are still tender||Cold and moist||1 week|
|Peppers||When fruits reach desired size or color||Like cucumbers||2 weeks||Develops pitting below 45°F|
|Potatoes||When vine dies back||Cold and moist; keep away from light||6 months||Cure at 50-60°F or 14 days before storage, will sweeten below 38°F|
|Pumpkins||When shells harden, before frost||Cool and dry||2 months||Very sensitive to temperatures below 45°F|
|Radishes||When roots up to 1.25 inches in diameter||Cold and moist||1 month||Store without tops|
|Rutabagas||When roots reach desired size||Cold and moist||4 months||Do not wax|
|Spinach||While leaves are still tender||Cold and moist||10 days|
|Squash, summer||When fruit are 4-6 inches long||Like cucumbers||1 week||Do not store in refrigerator for more than 4 days|
|Squash, winter||When shells harden, before frost||Cool and dry||2-6 months, depending on variety||Curing unnecessary; do not cure Table Queen|
|Tomatoes, red||When color uniformly pink or red||Like cucumbers||5 days||Loses color, firmness and flavor if stored below 40°F; do not refrigerate!|
|Turnips||When roots reach desired size, possibly after light frost||Cold and moist||4 months||Can be waxed|
|Watermelons||When underside turns yellow or produces dull sound when slapped||Like cucumbers||2 weeks||Will decay if stored below 50°F for more than a few days|
Source: Cindy Tong, Extension post-harvest horticulturist