Sizu Riatto
Grow by Numbers · Chapter 9

Fade: the Cold Chain

Cut greens fade, and warmth speeds it up. If shelf life halves every 6 °C, one measurement of your fridge tells you how long your packs last, and your harvest rhythm tells you how old the oldest one gets.

Home › Calculators › Fade: the Cold Chain

Opens on the book's Microgreen Shelf. Change any number to your own and press Calculate.

A warm trip (optional)

Your harvest rhythm

Enter the planned life and your fridge's temperature, then press Calculate.

The formula

  • Life at T = planned life × ½(T − base) ÷ halving step
  • Q10 = 210 ÷ halving step (how many times faster per 10 °C)
  • A trip uses its hours ÷ the life (in hours) at the trip's temperature
  • Oldest pack, sold oldest first = 2 × the harvest rhythm (at most two harvests in the fridge)
The book's worked example, Chapter 9. The plan: cut greens at 5 °C (41 °F) for 7 days. An arugula study (14 days at 4 °C, 7 at 10 °C) halves shelf life every 6 °C, a Q10 of about 3.2; at 11 °C it would be 3.5 days. A 2-hour trip at 23 °C uses 9.5% of a pack's life. Harvest every 3 days and sell oldest first: no pack is older than 6 days.
Check it. Put a fridge thermometer on the shelf where the packs sit and read it in the morning; then enter that, not the dial's number.

Honest limits. The halving step is a rule of thumb from one study of one leafy crop, inside the USDA handbook's Q10 range; your own greens, packs and fridge decide. Discard anything slimy, yellow or sour. The Microgreen Shelf was worked out on paper from published figures, not grown by us: weigh and measure your own. Prices are illustrative US prices from October 2026, shown without a currency sign; put in your own. Everything stays in your browser: no sign-up, nothing stored.

These calculators go with Grow by Numbers (Make It Add Up, Book 1), where every number on this page is worked by hand.