factors influencing flavor/sweetness

[Heritage]

I grow several OP tomato varieties in an unheated greenhouse in the San Diego area. Night temps are 40-50 degrees and daytime temps are 70-80 degrees F.
Every year the plants do great, set lots of fruit, and I have my first ripe tomatoes in early June. Unfortunately, none of the varieties have any taste. About a month later, all of the tomatoes taste fantastic. (For example, last year I had over 100 African Queen tomatoes in early June with no flavor. By mid-July they tasted great)

This wouldn't be a problem, except now I am growing out some F2 and F3 crosses in my greenhouse and have no way to judge the flavor except to wait.This defeats my purpose of growing 2 or 3 crops per season and develop a stabilized cross earlier.

I know genetics influence flavor but I am interested in which of the environmental factors have the greatest influence.

I am sure higher temperatures have some amount of influence on flavor and wonder if there is a "rule of thumb" for the optimum day/night temperatures needed to produce maximum flavor.

Another possible variable: when the fruit sets, the plant growth slows, allowing for more nutrients to the later trusses of fruit?

I'm sure there are other environmental factors influencing sweetness/flavor... I appreciate any thoughts on this.

-Steve

[Dawningstar1]

Geez you got me on that one, we have grown plants in a city where the ground was covered in gravel and roofing and we covered it with about 25 bags of black earth no special brand, and we planted tomatoes and they grew over six feet high, hubby says you got to make sure they have lots and lots of water and swear at them lol, he might be kidding on that one I just know we watered them to death and even though we only had a six foot plot I made 2 dozen jars of stewed tomatoes, got 12 big bags frozen in the freezer and gave away 24 jars to boot!!!

We never use any cemicals and never even used an manure although this year in my garden I plan to use some as the soil is very sandy and I am not sure how well Tomatoes will do in it let alone peppers and such although previous tenant seemed to do okay with their plants from what was still growing in Oct.....

Were your tomaotes juice when you first tried them, maybe you were like me and trying them before they were ripe lol.... but even then ours always have flavour, even Lily our smiling dog loves them....

[RandyG]

Light, water, temperature, and nutrition all have big effects on tomato flavor. Day temperatures around 85 and night temperatures around 60 should provide for good flavor. Day length is important and the time period from late May through mid July should be the best because it is the period of greatest sunlight. Limited stress for water will improve tomato flavor but at some expense in fruit size and the risk of blossom end rot if you don't water enough. The most effect from limiting water would probably come from cutting back on water about two weeks before the fruit start to ripen. High nutrient level in the soil, particularly potassium, is important for improving tomato flavor and of course maintaining as much healthy foliage cover for maximizing photosynthesis is important also. Also, do the first fruit you harvest have good seed set with lots of gel? A lot of the flavor components reside in the gel, and heavy seed set is needed for optimum gel formation.

The increase in flavor you see in going from early June to mid July may be due to increased water stress since the plants would be taking up more water as the days become longer and hotter and you have increased plant size and water demands from the developing fruit load. Unless you are growing a large number of plants and it is not feasible, you could start the next generation from all the best plants you select in early June for desirable fruit and plant characteristics and then discard the seedlings from the plants that don't develop good flavor by mid July. Just a few thoughts for consideration.

[Heritage]

Originally Posted by RandyG

Also, do the first fruit you harvest have good seed set with lots of gel? A lot of the flavor components reside in the gel, and heavy seed set is needed for optimum gel formation.

Randy, thanks much for the great information.

In addition to the lack of flavor, my first fruit didn't have any (or very few) seeds/gel, so I suppose the cure for this problem is more diligence on my part with my hand-pollination program?

Since I grow in pots, I'll also keep a closer eye on the amount of water after the first fruit sets. During the colder weather the earlier plants are, indeed, wetter than when the later fruit set.

Thanks again!

-Steve

[RandyG]

Steve,
I think the problem of poor pollination with your early set fruit is probably related more to night time temperature than vibrating the flowers to make them shed pollen. For good pollen production, night temperatures should not be lower than around 60 degrees. If the night time temperatures are going down to 40-50 as you indicated in your first post, you would not get much viable pollen .

[Heritage]

Originally Posted by RandyG

Steve,
I think the problem of poor pollination with your early set fruit is probably related more to night time temperature than vibrating the flowers to make them shed pollen. For good pollen production, night temperatures should not be lower than around 60 degrees. If the night time temperatures are going down to 40-50 as you indicated in your first post, you would not get much viable pollen .

OK, thanks... it sounds like a heater may be the best solution.

[Tom C zone 4/5]

I think low night time temps are part of your blah bland tomatoes. Try above 50F night time temps.

[RinTinTin]

Here in the PNW, we do not get warm weather until after the solstice, so our fruit don't begin to ripen until July/Aug. Even so, our later fruits are much more flavorful than our first sets, so I think it has more to do with temperature than day-length. This year we had fewer warm days than usual, and none of my tomatoes had their usual flavor.

[Heritage]

Originally Posted by Tom C zone 4/5

I think low night time temps are part of your blah bland tomatoes. Try above 50F night time temps.

Thanks Tom, the consensus seems to be that nighttime temps are an important key...

Now I'm wondering if heating the root zone alone to 60F is sufficient, or is it necessary to have the higher temperature at the bloom height.

And, is adequate viable pollen production alone enough to boost a 'blah' tomato into the 'good' flavor zone? Say, for example, could viable pollen from a heated plant be used to pollinate a plant growing with the cooler nights and still improve the flavor to some degree.

For my F3+ growouts a heater seems to be the only solution, but it would be nice to have ANY good tasting beefsteak OP in the winter. Especially if I could avoid the expense of heating my entire greenhouse.

[feldon30]

I think you want to heat not the roots or the blossoms, but the growing and ripening fruit. Otherwise, cool nights is like placing tomatoes in a refrigerator. This is why I've just about given up on fall tomatoes until I have a heated greenhouse.