Grow by Numbers · Chapters 11 and 12

Predict the Yield

Call it before you cut: the seed you sow times the crop's greens per gram of seed. Then weigh, and let the gap teach you your own ratio.

Home › Calculators › Predict the Yield

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

After the cut (optional)

Enter the seed and the crop's ratio, then press Calculate.

The formula

  • Predicted harvest = seed grams × greens per gram of seed
  • Packs = harvest ÷ pack grams (sell whole packs)
  • Gap = (weighed − called) ÷ weighed, ignoring the sign: within 5% scores 3, 10% scores 2, 20% scores 1
  • Your own ratio for next time = weighed ÷ seed
The book's worked example, Chapters 11 and 12. Radish: 28 g of seed × 10 = 280 g, 4.94 packs of 2 oz. The Crop Shelf's twelve ratios run from wheatgrass 1 and pea 1.5 to mustard 33.8; buckwheat has no published harvest weight we trust, so its first tray is yours to weigh.
Check it. Weigh the greens alone: tare the bowl first, cut above the mix, and never weigh roots or soil.

Honest limits. The ratios are planning figures from sellers and extension trials; your seed lot, sowing density, light and the day you cut all move them. 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.