Sheri,

This question makes my head hurt! lol I had to think about this one for a while, but I do have a few ideas of what might be behind the bitter flavor.

The times when I have had bitter-tasting tomatoes have been few and far between, and some of the time it has been my fault, while other times it is pests or the weather.

1) My biggest 'cause' of bitter fruit has occurred with the first fruits I pick from an unusually-colored tomato (any non-red type) and I pick them before they are fully ripe. This is normally due to my inexperience with that variety's color when fully ripe OR my overeagerness to try a new-to-me variety. Generally, I get it right the 'next time' I harvest from that plant. That is because I slow down, pay more attention to the hardness/softness of the fruit before picking it (ripe ones will be significantly softer than almost-ripe ones) and tend to get it right. This has most often occurred with black tomatoes (it took me FOREVER to get it right with Black Krim), green-with-ripe (I picked them while green when I should have waited till the skin had an amber tone to it) and orange ones (I picked them too soon when they were still a lighter orange when I should have waited until they were a deeper orange).

2) Excessively cloudy and/or cool and/or wet weather AFTER fruit set has occurred, i.e., while fruit are ripening. Tomatoes always taste best when they ripen under warm to hot and sunny conditions. They always have the ripest, fullest flavor in my garden when they ripen under EXTREMELY dry conditions. (My best tomato years are drought years.) You can tell the difference between a tomato that ripens in hot weather--for example, 95 degree days and 75 to 80 degree nights versus tomatoes that ripen in cooler weather--like 80 degree days and 60 degree nights. So, even though fall tomatoes are better than grocery store tomatoes, you may find tomatoes that ripen later in the fall, especially those harvested in late October and beyond, are not quite as flavorful as mid- to late-summer tomatoes.

3) My biggest cause of off-flavored tomatoes, though, is the damage they suffer from stink bugs. If your tomatoes have the kind of blemished skin that results from stinkbug damage, you may discover those tomatoes have an off-taste that is "yucky" and,I guess, it could be described as bitter. Lots of gardeners in zones 7-10 have the stinkbug problem every year and it can wreak havoc on your tomatoes' taste.

Of course, some tomatoes just have a more naturally acidic, robust, 'old-fashioned' tomato flavor, so it could be that Orange Oxheart falls in that category, but I have never thought of Brandywine having any bitterness in it.

If none of these options seems to offer a 'reason' that seems to resonate with you, then you might want to go to the Growing Tomatoes Forum and ask that question of the experts there. I am sure some, (like Carolyn, Hortist, Fusion, Gone Fishin', etc.) of them would have more ideas than the few I have come up with.

As far as I know, neither aphids nor whiteflies have such an impact on the flavors of your fruit, but then I haven't had a lot of trouble with aphids or whiteflies in my garden. If I do have aphids, it tends to be in very early spring prior to the occurrence of fruit set.

Could it be some kind of nutritional shortfall in your soil? I doubt it, since your other tomatoes have been pretty tasty prior to now.

I lean towards thinking it is the cooler September nights OR stinkbug damage, if you have or have had stinkbugs, but it is hard to guess long-distance.

Dawn

Dawn,

It could be stink bug related, because some of them have had similiar blemishes to pics I have seen of stink bug damage. I thought they were from the spider mites or aphids, as I had not seen any stink bugs. Then again, I haven't spent much time out there lately. I just wondered about those bitter cucumbers that I had left growing in between the tomato plants, I quit picking the cukes (they were hard to reach, and they were bitter) and left them there rather than disposing of the vine. I was wondering they could have gotten rootbound with the tomato roots or something bizarre like that....probably not. But some of the tomatoes off of the same Brandywine the next day were not bitter. Oh, I have had some kind of worm like problem on those same 3 plants, now that I am thinking of it. At least I think it is a worm, they are drilling holes down into the tomato from the top around the stem, they leave behind some kind of black debris on top of the tomato, I have been just cutting off the top and throwing it away. I think the bitter ones may have had those holes in them. My neighbor cut down his cedar trees behind us, and I have noticed those plants closest to that area are being attacked by something.

Sheri,

It doesn't take but a handful of stinkbugs moving from plant to plant to wreck the taste of your tomatoes. Stinkbugs are hard to control.

I like to carry a bowl of soapy water into the garden with me and flick the bugs off the tomatoes into the water where they drown.

You also can knock the stinkbugs off the plant and onto the ground and smash them with your foot, but they will stink!

Cukes get bitter in the heat, but that bitterness cannot transfer to your tomato plants.

There are always lots of caterpillars out and about in the fall. If they are causing unacceptable levels of damage to your fruits, you can spray the plants with Bt, but keep in mind that the use of Bt endangers all moths and butterflies in the area too. Since it is about time for the monarchs to migrate through, I hate to suggest Bt for anything, but it is an option. (Actually, the monarch's are late here.....we normally see them the first of October, but it has been too hot. I'm hoping that they 'come on down' with this week's cold fronts.)

Dawn

I suspect that too much water can cause bitter tomatoes among other problems. Water when soil looks dry...not when the plant looks wilted.