Approximate DTM? for fun

[AlittleSalt]

I have wondered about approximate DTM and if where you are gardening makes much difference? I'll use Big Beef F1, 73 DTM as an example - everyone has heard of Big Beef.

One Big Beef F1 plant is planted in zone 5 in New York at the optimal time.
One Big Beef F1 plant is planted in zone 9 in Texas at the optimal time.

Both places get the right amount of rain, no bugs eating them, no diseases, no Roundup overspray, and since we're pretending those things don't exist - the soil PH is the same with the same nutrients in the soil.

Would the DTM be the same? Or would the sun intensity difference between the two locations change the approximate DTM?

I'm just curious.

[Rockporter]

I'll bite on that one although I am of course not an expert on anything. lol.

My understanding is that the northern states usually plant early DTM so they can get a good crop before it gets too cold. Anyone?

[Gardeneer]

I think DTM will vary in different climates.
Even though I could plant out on/about April 10-15 in Seattle , WA (zone 8a) and do that in Southeast NC ( zone 8a), I wont get the same DTM, for sure. I can guesstimate that there will be at least a 15 days difference.
Case in Point:
For years I planted early April in PNW. The earliest firs ripe tomato I ever had was around July 15th.
Those tomatoes (Siletz , Bloody Butcher ) had a listed DTM of 65-70 days but it was actually 85- 90 days. There is a minimum of 15 days gap.
IMO, consistent warm day and night temperature can speed up fruits growing and ripening.

[KarenO]

daylength is a factor that helps even the score a bit from north to south. Long day-lengths in my former zone 3 Northern Alberta garden helped make up for a shorter season. I always had ripe full size tomatoes in July. Pretty much the same timing here in my Zone 8 PNW garden as far as DTM on my varieties.
not as much difference between New York and Texas but if you went further north I think daylength plays a role although difficult to say how much.
KarenO
KarenO

[NarnianGarden]

Yes, daylight length does matter. Our days are getting shorter but they're quite long in the month of June - which may not always be the best for tomatoes either..

[brownrexx]

Growing conditions definitely make a difference. 3 years ago I had 2 Big Beef seedlings planted at the same time. I planted one in the garden in a cage wrapped with clear plastic and with water filled jugs to retain warmth on April 30. I planted the other seedling in the ground on May 17.

Both plants had their first ripe tomatoes in the middle of July. The earlier planted tomato was no bigger and did not product a ripe tomato any earlier so it's DTM was actually 3 weeks longer in the same soil in the same garden, grown from the same pack of seeds. The only difference was day length and temperature.

[ABlindHog]

I get stuck on this question at defining optimal planting date. Last year I planted Break O' Day from 5 week old seedlings on March 15 and on July 15. My Spring tomatoes took 69 days, the fall seedlings produced in 56.

[My Foot Smells]

I have no idea how DTM is determined? Maybe if they were grown in a test tube, but lots of factor to consider.

I get confused on DTM whether that is when the seed is PLANTED, or when the transplant is PLANTED. I dropped seed Feb. 1, planted at the end of March and did not get tomatoes until the second week of July (first mature that is...)

so that's like 100+ days from transplant and heck of a lot more from seed drop. I don't think getting tomatoes before July 4th (full size interdeterminate) is likely if planted outside at my location (8a - used to be 7b)

....but when they DO come, it is usually an avalanche for about a month.

[b54red]

The warm temperatures of the south make a huge difference in DTM. Even down here it makes a huge difference in DTM whether a variety is planted in the cooler weather of March or in the warmer months following. I have seen a full two weeks difference in many varieties planted in early spring as oppossed to the same variety planted a month or two later. However there seem to be some varieties where really hot weather can actually delay ripening but I haven't seen too many of those and they are usually early type hybrids. I can remember trying some of them in summer plantings thinking they would make early before the cooler weather of fall got here but they were much slower ripening in the heat than they were in the cooler spring weather.

Bill

[AlittleSalt]

There is so much to learn about growing tomatoes. There are so many different factors weighing in on how they grow or not. DTM has puzzled me. Below is a picture of a Rebel Yell tomato that is growing (Which is supposed to be 80DTM) This plant was planted in the ground 6 weeks ago in late June. It was very hot here in July - daytime temperatures near or above 100F. So far, August has lower temperatures with highs in the 80s and low 90s. (Not typical August weather here.) The other two pictures of flowering Campari F2 plant - who knows about an F2's DTM? It is odd seeing flowering tomato plants in August here. There is also a Big Beef plant flowering. The Campari and Big Beef plants were planted almost a month ago.

[Worth1]

I heard they were developing a millennial tomato, it never matures and wont leave the garden.
Worth

[SharonRossy]

Ha ha ha! Good one Worth! Love it!

[bower]

In my experience DTM is affected by both daylength and temperatures. Longer days leading up to transplant lead to earlier maturity.
Also the standard "DTM" given on a package is 'days from transplant'. This year I had to hold back my plants for weeks past the time they should have been transplanted out. Some varieties were affected more than others, but overall, maturity was delayed, and in some cases the same variety started weeks earlier had only a day or two advantage.

[Gardeneer]

In my Opinion , day length is not a big factor. Reason being that day length ( From April to September ) is longer ( in the northern states and Canada than the south) but DTMs are considerably lower in the south than North. I believe that temperature are much determining factor than anything else. For example , the night lows will stay under 60F in PNW well into July and day highs will rarely reach 85F or higher. So in a temperature range of 50F to 75F it will take much longer for tomatoes to mature and ripen. I know this by experience, as I have gardened in the south ( ATl, Ga , NC ) and in the PNW. They all have roughly the same USDA zone , same LFD but the similarities end there. You have to looks at the average temperatures in 24 hours and something called "Heat Zone".

[imp]

At first, just reading the headline, thought you meant DTM for all us gardeners!!