Block the Ethylene & Hold the Firmness

1-MCP (1-methylcyclopropene, sold commercially as SmartFresh) is a gas that binds irreversibly to the ethylene receptors in plant tissue. Ethylene is the hormone that triggers ripening and senescence; by occupying the receptors, 1-MCP blocks that signal, so treated fruit softens, yellows and respires more slowly. It is a blocker — the exact opposite of ethylene gassing, which is used to ripen fruit. Effective doses are in parts per billion (ppb), applied in a sealed room or chamber for an exposure period.

Only if the commodity is climacteric (ethylene-driven ripening) and responsive. Apple, banana, tomato, kiwifruit, avocado, persimmon and many cut flowers respond strongly and gain weeks to months of shelf life. Pear, plum, apricot, mango and melon respond moderately. Peach and lettuce respond weakly. Non-climacteric crops — citrus, table grape, strawberry, sweet cherry — gain little or nothing, because their ripening is not ethylene-driven. The tool flags the responsiveness class for each commodity.

Typical effective doses range from about 150 to 1000 ppb depending on the commodity; apple is often treated at 600–1000 ppb, banana at 200–1000 ppb, and many flowers at 200 ppb. The tool recommends the midpoint of the published range for the chosen commodity. The registered SmartFresh label rate and local regulations govern the actual commercial dose — always follow the label.

Exposure is usually 12 to 24 hours in a sealed, gas-tight room. Receptor binding is faster when warmer: the tool scales exposure with a Q10 of about 2 relative to a 20 °C reference, so storing or treating 10 °C colder roughly doubles the exposure time needed, and 10 °C warmer roughly halves it. Cut flowers need only a few hours; firm-storage fruit need the longer end.

Before the climacteric ethylene burst. Each commodity has an apply-by window — about 7 days for apple and kiwifruit, but only 2–3 days for avocado, banana, tomato and apricot, and 1 day for cut flowers. Applied within the window you capture the full benefit; applied later the receptors are already triggered and the effect decays toward a floor of roughly 20% of the potential gain. The tool shows the window, the days left, and the reduced gain if you are late.

It depends on the commodity. A high responder like apple can move from around 120 days to roughly 190 days of firm storage (a 60% gain), banana can extend its short green-life by 80%, and tomato or kiwifruit gain 50–70%. Moderate responders gain 30–40%. The figure assumes treatment inside the apply-by window and proper cold storage afterward — 1-MCP slows ripening, it does not replace the cold chain.

Because they are non-climacteric: they do not show the ethylene-driven respiratory and ripening surge that climacteric fruit do. Their quality at harvest is essentially fixed, and storage life is governed by temperature, humidity and decay control rather than by ethylene action. Blocking ethylene receptors therefore gains them little, and the tool reports no meaningful shelf-life extension.

Yes, in some commodities. European pears treated with too high a dose can fail to ripen properly afterward — they stay hard and never reach eating quality. That is why pear is treated carefully at the lower end of the range. For most fruit, the risk is the opposite: under-dosing or treating too late simply gives a smaller benefit. The tool's recommended dose sits in the published safe range, but always confirm against the product label for your crop.

No. 1-MCP slows the ethylene signal, but respiration, water loss and decay still proceed, just more slowly. The shelf-life figures here assume the fruit is held at its correct storage temperature and humidity. Treat 1-MCP as a multiplier on a good cold chain, not a substitute for it — a treated fruit left warm will still ripen and spoil.

No, but they are complementary. CA storage lowers oxygen and raises carbon dioxide to slow respiration; 1-MCP blocks the ethylene signal directly. Many apple programs combine both — a 1-MCP treatment soon after harvest plus CA storage — for the longest firm storage. They tackle different parts of the senescence pathway.

If you are already past the apply-by window, the effect is sharply reduced — often only a fifth of the potential gain — so treating an over-mature lot is rarely worth the chamber time and gas cost. The better decision is usually to sell the late lot promptly and reserve the 1-MCP treatment for the next, freshly harvested lot applied inside its window. The tool shows the days left and the reduced gain so you can make that call.

No. The calculation runs entirely in your browser using the built-in commodity response table and the exposure/timing model. Nothing you enter is sent anywhere.