oh, and I do have aphids and white flies this year (and stupid rotten horn worms! ugh!).

I dusted once with Bonide garden dust, that was about 4 weeks ago, just before the run of hot humid weather.

I spray once a week with safer, either the insect or the 3 way (insect, fungus & disease one).

Of course I only spray at night, after the bees have gone, and I avoid spraying on really hot days or eves.... The last 3 weeks weather has been gorgeous tomato weather... high 80's day, high 60's night, a little rain, but low humidity.

Do you think my spray might be gunking up the blossoms?

buck1173 - I feel your pain, do I ever. Blossom drop is usually associated with very high heat and humidity. I'm sure there can be other causes that I'm unaware of. My thoughts wander to the presence of whiteflies and aphids, both carriers of assorted viruses that are detrimental to our crops. That 'may' be the cause of BD also. Unfortunately, aphids and whiteflies linger on the bottom of the leaves and are difficult to even get at on a well developed plant. In the past I've gone out with a spray bottle of shampoo and water to wet the underside of leaves in the early morning. Not alot of shampoo, mind you, just enough to make the water wetter. It penetrates the breathing apparatus of those soft bodied critters and drowns them on the spot. I've also found that by using very little fertilizer, although some, the plants are resistant to invasion by those two. Also a goodly amount of vermicompost around the plants builds resistance amazingly well. I hope all this helps. And we'll be sharing that heat wave with you for the next few days. Best of luck.

Kindly, what are all the possible reasons that spring to mind for BD?

*****

I'm pretty sure all or most of these are also in the FAQ you referred to.

1) High daytime sustained temps over about 85F, the temps differ for different varieties, and those high temps lead to denaturation of the protein pollen so that it's no longer viable.

2) High humidity b'c the pollen clumps and is much less effective.

3) Too much N or growing in too rich soil which is a stress to plants and that stress can lead to lack of blossoms and/or fruit set and thus blossoms drop. It can also lead to BER as well.

4)Night temps above about 70F can also lead to blossom drop.

(Lack of anything? Too much of anything? Certain strains just like to drop blossoms?)

Not lack but perhaps too much N as I mentioned above.

The only variety that I know of that has a reputation of having problems with blossom drop is Brandywine.

Since blossoms self pollenmize about 95% of the time no insect pollination is necessary since most of that time the self pollenization occurs before the blossoms are fully open.

If pollen is not viable b'c of High day temps or b'c of high humidity all the shaking in the world is not going to increase fruit set IMO.

And no, again IMO, spraying is not going to affect fruit set.

The blossom cycle is about every three weeks and since blossoms appear asynchronously on a plant that means that as soon as conditions are favorable fruit set should continue and blossom drop percentages go lower.

Yes, starting today thru about Monday it is supposed to be wicked hot with high humidity here on the East Coast area. I'm thinking of me who hates that kind of weather, but I'm also thinking of my tomatoes. ( smile)

And if I've forgotten any of the major common causes of blossom drop I'm sure someone will add to what I said above.

Carolyn

jbann, thank you.... yes I recently read that an overly fertilized plant will indeed attract more aphids. Nice tip on the vermicompost! thank you!

Carolyn, thank you so much. Yes, you did cover everything in the FAQ, but in broader detail which I really appreciate!

I find it interesting you mention some varieties are more tolerant than others of high temps. Though I did know that there are specialized varieties for more extreme climates, I was curious if there was a milder swing of tolerance within more general varieties. I appreciate knowing that.

[touch wood] BER is not something I've experienced yet, but my soil possibly could be too rich. I amended my beds heavily last year with about 4 tons of composted horse manure, then sowed winter rye, then turned it all in in February. That could be. Because I have a good deal of blossoming going on, and even had some isolated chlorosis, I didn't dare dream that my beds are too heavy on the N.... I was under the impression that a signal of too much N was lack of blossoms... however, as I read your response, I'm now understanding that too much N can allow for lots of blossoms, just no fruit set? Interesting and valuable to know... thank you.

Thanks for the note on the blossom cycle... I kinda figured that by watching the plants daily, and thats what prompted me to post here.... the last 3 weeks have been ideal weather, waves of new blossoms came forth, yet the blossoms drop anyhow despite seemingly ideal conditions.

Brandywine actually comes to mind as being one of the few that is having little blossom drop, though they are not bursting with blooms either.. I have Pink and Red going.

Off the top of my head the worst are: Prarie Fire, Tigerella, Bush Champion, Black Krim, Beefstake, Watermelon, Grushvoka (sp?). Riesentraub (sp?) is also suffering significant loss, but its putting forth so many blooms its almost negligible.

Dark horses (plants I didn't think would make it) like earls faux, carbon, and red currant in the meanwhile are thriving....

And the plants I didn't think had a prayer of making it because they're so sick and twisted (Banana Legs, Giant Valentine and now most of my romas) are spitting forth fruit after fruit after fruit, despite having virtually no foliage.

Is this a strange year? or is it just me? : )

Perhaps I'll go get my soil tested, not that there's much I can do about it I imagine....

thanks for your help.

Lack of nitrogen and/or lack of phosphorus can be an issue. Think about this if you happen to be in sandy soil which may have low amounts of organic matter. I wouldnt go adding anything though unless the soil is sandy. Most tend to over-fertilize.

Other reasons for blossom drop
Blossom Drop

I dont know specifically what is causing it but I looked at several NWS weather trends for several places in NJ that could be considered 6/7. Seems like you had some slightly high night time temps up till about the July 10th which could be a factor (they really werent that bad). The charts dont account for humidity and even though its been gusty the winds havent been that high to make a difference. It could be a combo of higher temps, humidity and variety.

If weather related I generally dont see flowers drop till after they open and fail to pollinate/fertilize. If nutritionally related it could be before they open or after that they drop. Nutritionally stressed (too little) flowers are often small and the smaller later ones often shrivel and dry up before they open. There should be other signs of too little such as slow growth or pale green/yellow color to the older leaves or entire plant. Too much N and the plants will appear vigorous and healthy but the flowers shrivel up. That might help clue you in some on those issues.

As for insects, tap a few flowers onto a white sheet of paper and see if thrips come out. Also look for aphids. They can suck the life out of the flower. Both could be adding to the stress which is making them drop but still I suspect temps and humidity.

Also,

"The blossom cycle is about every three weeks ..."

As someone who spends in inordinate amount of time crossing flowers I do not find 3 weeks to be the case. So don't worry about waiting too long.

The blossom cycle that I observe is more like 4-7 days between clusters once the seasons starts. There is an overlap of opening flowers between clusters. With this cycle I can cross a new flower on the same plant almost every day. That is what is going to matter to you for set. I would say that the time from one flower cluster to the next developing happens really fast once the plant gets to a certain stage. My guess is that you are only looking at a matter of 7-10 days at the most this time of year.

As the FAQ mentions try mulching. Mulch DEEP. Cooler roots have been shown in studies to increase fruit set in warmer weather. These studies also looked at rootball depth which was a factor. Since you probably shouldnt plant them deeper at this point be sure the mulch is deep. Not only do you have the radiant energy from light but you have the infra red energy which penetrates deeper than the light can to consider. Be sure to water before spreading the mulch.

The blossom cycle is about every three weeks ..."

As someone who spends in inordinate amount of time crossing flowers I do not find 3 weeks to be the case. So don't worry about waiting too long.

****

Keith, I was only repeating what I've read online at University sites, and no, I can't pluck a link out of the air. I don't spend an inordinate amount of time checking blossoms and don't do crosses, so if your experience says much less than that, so be it for your area with your weather and all the other variables. ( smile)

Carolyn

wholey molely mule you rock!!! btw, mules are about my fav. creatures on the planet! right up there w/ horses & trout

This is a ton to think about, thank you! Yes, I have noticed BD in many stages - yellowing then dropping at the joint, whithering and shriveling and staying on, etc, etc,

thank you!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Contrary to what a lot of people have said, tomatoes like water and lots of it, but they don't like sitting in water. I water mine every other day, unless it rains. I plant them high and dry, give them what they like best water and compost.

Since blossoms self pollenmize about 95% of the time no insect pollination is necessary since most of that time the self pollenization occurs before the blossoms are fully open.
*************

Carolyn,

If I harvest seeds from a heirloom tomato whose bloom was not bagged; is there a 95% chance the seeds will be true (not cross polinated)?

John

Contrary to what a lot of people have said, tomatoes like water and lots of it, but they don't like sitting in water.

Interesting observation, rfonte. Perhaps in your zone that may be true. Further north, not so much. I find that "lots of water" leads to lots of very watery tasting fruit, yellowing plant leaves, and increased blossom drop and BER problems. In fact many commercial growers do what is called dry farming for those reasons.

If I harvest seeds from a heirloom tomato whose bloom was not bagged; is there a 95% chance the seeds will be true (not cross polinated)?

Yes John, that is what we are saying. That is why seed saving for one's own personal use is fine regardless of plant spacing. If saving seeds for sale or other commercial purposes then more care is required (ie: bagging blooms).

Dave

Dave, whats dry farming?

~~~ and increased blossom drop and BER problems. In fact many commercial growers do what is called dry farming for those reasons. ~~~

Hmmm. This is one of those "takes all kinds" moments.

I am finding that younger plants (or could it be cooler temps?) do suffer BER more when more moist but the plants are growing so, I can't deprive them of it too much. Older plants, seem to get it more if allowed to dry out too much.

I also find that heavy fruit setters, excluding cherrys, are more suseptable as are unpruned plants and those in smallish containers.

This yr. only plants in 8gal and smaller have suffered BER so far with 2 exceptions. One German Queen (she was finiky last yr too but the taste, Oh my!) tom in a 2 cubic ft. container and for the first time I remember I had to toss a half doz from one inground plant, Health Kick. Health Kick is in my "gorilla site" and virtually ignored ... no pruining, almost no suplemental water or feed.

As to the prunng, I've just about convinced myself and will be sharing some photos that show that moderate amounts of pruning are beneficial if you want early fruits. Purdue has already shown a size increace.

No, its not a lab grade test. Some of it you'll have to take my word and some extrapolation made. Numbers are not in question, pruning reduces numbers but to me, even though less flavorful than those when the heat comes, early tomatoes are valuable.

I am having problems with my blossoms also on my squash plants. As soon as they open they seem to start to wilt then rot away. Please help as i am unsure what to do at this point.

Buck - "dry farming" is no supplemental water - rainfall only. Although it produces smaller fruit many swear it has the best taste.

But we have to keep in mind the many basic differences between container growing and in-ground growing. You really can't compare or interchange advice with the two approaches. Like you can't dry-farm in containers. ;) And containers generally need larger amounts of both water and nutrients than in-ground plants but it is still quite possible to over-water container plants. Not to mention the differences in soil, make-up, weather, etc. that varies from zone to zone.

So when broad statements like "Contrary to what a lot of people have said, tomatoes like water and lots of it, but they don't like sitting in water". they need to keep in mind that what works for one doesn't necessary work for all. ;)

Dave

PS: Coastie - check out all the problems with squash discussions on the Vegetable gardening forum. If you are talking about your blooms "open then wilt and rot away" that is normal. If you mean the squash themselves are rotting then it is more likely fruit abortion from inadequate pollination that is the problem. Check out the FAQ on hand pollinating as that is what many are doing this year. Good luck.

Thanks Dave. It is the blooms not the squash. but it seems that the leaves are wilting now. They have not turned brown just started to wilt. they get plenty of water and are fertilzed properly. my only guess is that it is way to warm and humid here is mass.

Dave, you are so wise and all knowing... thank you!

wish there was an edit on this forum.... seriously dave, thank you for that advice last year to water less, mulch more, its been a much nicer year thus far for me thanks to that tidbit... the slow pick of maters this year so far have been vastly tastier too.