Real Shelf Life of Microgreens by Crop and Temperature

"Keeps up to 10 days" on a label means nothing until a temperature stands next to it. The same tray of radish holds saleable condition for two weeks at 36°F (2°C) and less than two days on a kitchen counter. Variety and packaging have nothing to do with it: leaf senescence is a chemical reaction, and temperature sets the rate. What follows collects the shelf life stated on every crop page of this site, together with what each of those figures becomes at the temperatures a real store actually runs.

Quick glossary: Senescence - natural aging of a cut leaf: chlorophyll breakdown, loss of turgor, development of odor. It starts at the moment of cutting and never stops; cold only slows it. Cold chain - unbroken temperature control from cutting to customer; it breaks at the transitions, not in the stationary chiller. Pre-cooling - bringing the product down to 36-39°F (2-4°C) immediately after cutting, before packing.

Shelf Life After Cutting, by Crop

The last column is the temperature stated on that crop's own page. It is blank for a reason: 38 of the 70 crops give no temperature at all, and their figure has to be read as "refrigerated" without further detail. That is a gap in the data rather than a property of the crop.

The spread inside a single group reaches sevenfold: parsley holds two weeks, oregano one to two days, and both sit under "herbs". What drives it is surface area and tissue density. A small firm leaf with a thick cuticle loses water slowly; tender aromatic greens with large surface area per gram wilt and darken within a day.

Temperature: What Each Degree Costs

Aging rate is a direct function of temperature. The working guide for leafy greens: every additional eight to ten degrees roughly doubles the rate of decline.

A partner store's chiller typically holds 39-46°F (4-8°C). That means a product for which you honestly measured 10 days at 36°F (2°C) in your own fridge has 5-7 at the point of sale. The difference is built into the chain and has to be subtracted when you set the date, rather than explained away later when complaints arrive.

Basil and Cold: The Exception That Breaks the General Rule

Four crops in the table state 50-54°F (10-12°C), and all four are basil. The reason is chilling injury: basil is tropical in origin, and below roughly 50°F (10°C) its cell membranes break down. The sign is distinctive and easy to recognize: leaves darken to almost black within hours of coming out of the fridge.

The practical consequence is awkward. Basil cannot travel in the same cool box as brassicas if that box holds 36-39°F (2-4°C). Either basil gets its own regime, or it gets a deliberately shorter date and fast turnover. Lemon balm, shiso and mint are sensitive in the same direction, though less severely.

Where the Chain Actually Breaks

The chain breaks at the transitions, and every break comes out of the date on the label. The most expensive is the first hour between cutting and the cooler: the product is still warm, respiration is at its peak, and later refrigeration does not give that hour back. Then come the packing area, transit and store receiving, where product temperature most often first crosses 39°F (4°C).

Temperatures and fixes for each transition are collected in the article on packaging and the cold chain. For shelf life they add up to one rule: the date on the label is set by the worst transition that actually happens in your chain.

Three Mistakes That Cost the Most

Putting the laboratory maximum on the label. If the product holds 10 days in your own fridge at 36°F (2°C) with an unbroken chain, that is a ceiling under ideal conditions. Real chains always have gaps. The date belongs to the distribution conditions, and the difference between those two numbers is usually about a third.

Washing before storage. Free moisture on a leaf at 39°F (4°C) is a growth medium for bacteria, and it eats shelf life faster than any temperature error. Wash before eating, not before the fridge.

Never inspecting the product at the end of its date. If nobody has looked at how a batch appears on day seven at 46°F (8°C), the date was set blind. The test is simple: put a packed batch in a chiller set to your partner's temperature and check it daily until the date and for two days after.

How to Know the Date Is Set Correctly

Product temperature at receiving does not exceed 39°F (4°C), and that is measured rather than assumed. At the end of the stated date, at real shelf temperature, the product is green, turgid, odor-free, with no condensation inside the pack. Spoilage complaints before the date are isolated and traceable to a specific failure rather than recurring batch after batch. The label date is lower than the laboratory maximum, and you can state that difference as a number.

If you want to go deeper: Senescence: What Happens to a Leaf After Cutting explains the reaction itself, and Packaging and the Cold Chain covers how packaging manages the atmosphere inside.