Check out some similar questions!

mkurth001 · Jul 7, 2007, 02:39 PM

What causes green tomatoes to fall off the vine before they are ripe?

binshtok · Aug 14, 2009, 01:17 PM

What causes tomatoes with dark spot on bottom while still on the vine?

KUXJ · Aug 26, 2009, 07:50 PM

Originally Posted by mkurth001

What causes green tomatoes to fall off the vine before they are ripe?

Possibly fruit rot or soft rot (Phoma destructiva Plowr)

This disease is destructive to both leaves and fruit, causing a spotting, and if neglected, will cause them both to drop off.

Remedy---Spray with Bordeaux mixture.
Bordeaux Mixture
By F. E. Meyers & Brothers

Copper Sulphate (blue vitriol)------------- 4 lbs.
Quicklime (not air-slaked)----------------- 4 lbs.
(Of dry air-slaked lime or hydrate of lime one-fourth more).
Water to make----------------------------- 50 gals.
Dissolve the copper sulphate by putting it in a bag of cheese-cloth and hanging this in a vessel holding at least 4 gallons, so that it is just covered by water. Use an earthen or wooden vessel. Slake the lime by addition of a small quantity of water, and when slaked cover freely with water and stir. Strain the milk of lime thus made into the copper sulphate. Pour more water over the remaining lime; stir and strain into the other until all lime but stone lumps is taken up, and then add sufficient water to make 50 gallons in tank. Thoroughly agitate mixture, when it will be ready to apply. The mixture should be made fresh before using, and any left over for a time should be thrown out or have fresh lime added. The above is the 4-4-50 formula. Can be used up to 6-6-50 just before bloom on apples or potatoes.

The above is for rots, molds, mildews, and all fungus diseases.

All this can be found Here

Originally Posted by binshtok

What causes tomatoes with dark spot on bottom while still on the vine?

That would be blossom end rot... A lack of calcium in the soil.
You could have your soil tested for next year, but I usually add crushed eggshells to the garden

K

lingdoc1 · Jul 25, 2011, 04:15 AM

Earthquakes, tsunamis, shaking the plant violently and kicking it when drunk, are all reasons that could cause the tomatoes to fall off too early... but usually the abscission zone weakens during cool periods, and also as a result of decreased nitrogen content in the soil. SO I would recommend that you cuddle up naked in a sleeping bag with the affected plant (that is what we would do in the arctic) and spread some organic Nitrogen-rich fertilizer (also known as COW POOP) around the plant. Hope this helps