How long does it actually take from sowing a tomato seed to picking fruit?

Between sixty and ninety days from transplanting, or roughly one hundred to one hundred and thirty days from sowing seed, depending overwhelmingly on variety and temperature.

The stages are reasonably predictable. Germination takes five to ten days at twenty to twenty-five degrees. From germination to a transplant-ready seedling is another five to seven weeks. From transplanting to the first open flower is about three to four weeks, and from pollinated flower to ripe fruit is another six to eight weeks.

Variety is the biggest single variable. Cherry types such as Sungold or Gardener's Delight often ripen in fifty-five to sixty-five days from transplant. Standard slicing tomatoes run seventy to eighty. Large beefsteak varieties frequently need eighty-five to ninety-five, which is why they disappoint in short-season climates — the plant runs out of warm weather before the fruit finishes.

Temperature sets the pace within that. Tomatoes essentially stop developing below about ten degrees and set fruit poorly above thirty-five, when pollen becomes unviable. A cool cloudy summer can add three weeks to a variety's stated days-to-maturity, and seed packet figures generally assume good conditions.

Two practical consequences. Count backwards from your last expected frost or the end of your reliable warm weather, add the variety's days to maturity plus about six weeks of seedling time, and that tells you when to sow. And if you are in a marginal climate, choose determinate or early varieties rather than fighting the calendar with a beefsteak.

Ripening at the end of the season can be nudged along by removing the growing tip and any flowers that will not finish, so the plant puts everything into the fruit already set.