I don't know, seems a little over simplified to me. Daytime would also play a role, in addition to nights as well as 10,000 other factors. Maybe all other things being equal you could simply say "below 50, add a day" but rarely are all other things equal.

Plus, I think fruit ripening is something that is still not 100% understood, as is the case with most plant habits.

"There is no end to questions on how plants function, but, unhappily, few positive answers can be offered... In an age when people have walked on the moon and lives are saved with transplanted organs, it is humbling to admit that routine functions in seemingly simple plants still baffle us."

~Brian Capon, Botany for Gardeners

Steve, here the night-time temps don't get out of the 40's and low 50's until july, and its only mid-july they're in the high 50's and when it hits 60 at night, right before the monsoon in early August, we all complain about sweltering night time temps, actually take off a blanket.

So I've mentioned before that with my garden, it doesn't matter what they say about 'days to maturity', or early, mid-season, or late season, because they all mature at the same time, late August/early Sept.

IOW, your guy may be right.

I used to seriously resent the information on days-to-maturity found on seed packets and in catalogs. I'd have been embarrassed to share ripening dates in my garden for 65 day varieties, or whatever. A "good" gardener should be able to overcome environmental shortcomings, right?

Some folks have described these ratings as something like "ideal" growing days. Well, what does that mean?

Then, I learned that commercial farming outfits were given Growing Degree Day ratings on when to expect harvest for things like corn varieties! Why in heaven weren't the gardeners given that for what they are growing? The Weather Service keeps track of GDD's for us.

If it comes down to growing season warmth, this would be better than some guy at a catalog outfit making something up out of the thin air.

Of course, " all other things being equal " is a concern. Fertilizing could be a very big deal. But, I kinda like having some rules of digits.

I usually remove all tomato blossoms when I set the plants out. Miss a few but if I can do a little better job here in a few days, I can eliminate the chance that any plant set fruit before transplanting. Then, I can check the WS records for sub-50's nights when I'm finally able to pull a ripe fruit from the vines.

There were 23 of those sub-50 nights from the 21st of May onward, last year. If I had a ripe tomato on August 15, that would be 78 days. . . . I don't know, checking this year on a few varieties might reveal something useful.

Steve

This post was edited by digit on Sun, May 18, 14 at 15:47

I've just learned to disregard so much of the "common knowledge" over the years. I listen to growers with the same conditions I have, or similar. People from other regions have totally different growing conditions, but are very eager to tell us what "should be." Well, I see "what is" and go from there.

Frankly, even though we have obstacles many cannot imagine, the cool nights, hot days, and the aridity make for some very tasty produce. I've fretted many times when temps dipped into the mid-30s in June. I still get maters come August (unless hail wipes me out).

I second the "there are way too many factors" to be able to determine how many days until harvest. Further, with "tenders," there are some varieties that are more adapted to colder nighttime temps, I think that those are the "early" versions, in tomato-speak? I have one variety this year that is supposedly 50 days, so we'll see.

Of course, I have one variety of seed in my stash (I've never planted it) that is supposed to be so reliably self-polinating, and able to tolerate much cooler temps that it's supposed to be able to bloom and set fruit before you even see the bees. I can't remember what it is called offhand (maybe an "Arctic" variety?), but I do remember that what research I was able to do indicated the flavor wasn't worth the plant taking up a spot in my garden.

All I know is when the first 'mater comes, it happens, and I can't wait to sink my teeth into something better than the pink mealy things that I occasionally break down and have in the wintertime. I'm in the beggining to harden off phase with my seedlings now, and my babies braved the cool last night--I think it got down to 57, which was warmer than the predicted 50. Do you think 3 degrees would make a difference, had they been planted out? This is where the debate really gets silly (considering the "all other things are never equal" angle), does 59 matter? what about 58, 57? 55? When does that extra degree REALLY make the first harvest later?

Ultimately, I use the "days to maturity" as a guide to try and figure out which tomatoes will be likely coming earlier and which will be later in the grand scheme that is my garden. And I take it kind of like I take the weather forecast: besides baseball batting averages, the only folks that can be wrong SO often and still keep a job are those that predict the weather--and when I'll get my first tomato!

No, not 60o overnight. I'd be waiting forever.

The idea is that an overnight of 50o results in no growth, suspended development. The 60o recommended minimum is for greenhouse growing.

Yes, I have realized that the days-to-maturity only works for me as a comparison. And, it is far from accurate. I have avoided varieties that I expected to be disappointing. It's getting better because there are now a good number of old friends in the tomato patch that I can rely on. There is now a slight willingness to try a couple varieties each year that I suspect won't come thru.

Your "Arctic" tomato is probably one of the "Sub-Arctics" - some that I felt forced to grow back in the '70's when I gardened about 500ft higher in elevation.

Steve