I transplanted my tomato plants outside early this year when they already started blooming and the weather is still cold. Flowers start falling due to lack of pollinators (absense of bees).
Some types of tomatoes can be pollinated well by wind or shaking, but others do not. They release pollens in responding to viberations at a certain frequency only, which is usually the frequency of the bee's buzzing (bumble bees are the best pollinators to tomatos).
When I see this problem, I use an electric toothbrush (I use a type of Sonic Oral-B with three viberation modes and the middle mode is close to the frequency of bee's buzzing) to gently touch the flowser stems. During the viberation, I can even see pollens bursting out from the small hole of the flowers. Since then, no flowers fall, and magically, each turns into a fruit. I've already got some turn to red!
Tomato pollen is not in the exterior like most flowers, rather it resides internally and then released through pores in the anther. I don't see how q tip will work unless you do "surgery" to open the flower without hurting the inside structure? Motion is required to release the pollen, and the greatest quantity to be released is by sonication in certain frequency.
Tomato is originated in the highlands of the west coast of South America where a species of halictid bees were their native pollinators. As tomatoes were moved from their native areas, their traditional pollinators did not move with them. Domestic cultivars of tomato have been selected to maximize the trait of self-fertility, i.e., the capibility being pollinated by alternative ways such as in wind or shaking.
Shaking by wind will release pollen. But not all types of tomatoes respond to wind the same. Most commercially chosen types to grow for open air will respond to wind very well. But if you are growing those rare-to-find species, wind may not be enough (that is why they are not selected for commercial production).
The most effective pollination is to be vibrated at a specific frequency by the native halictid bees. Honey bees are unable to vibrate the tomato flower in this way, but bumble bees and some other native species can. The size of the fruit is dependent on the number of ovules fertilized. So we want to get pollination as full as possible. This is the reason the bee is best, it delivers the most grains of pollen, exactly where it is needed, on the sticky surface of the stigma. Even for species responding to wind well, according to research, bees can still significantly increase the productivity and you'll get bigger and juicier fruits.
Without bees, an electric toothbrush will do the trick - if you just grow a few tomato plants.
Too much water and too much nitrigon will result a lush foliage growth with less blossom and fruits, and produce less tasteful fruits and cause slow ripening. This is the typical mistake that many home gardners make.
Cool soil could also be the problem. Try to use black plastic sheet to cover the ground when the whether is still cool. Avoid watering in late afternoon. Instead, water them in early morning, so the soil can warm-up during the day. When the weather becomes hot, cover the ground with straws ot multch to prevent over-heating.
When use commercial sparying product to enhance fruit setting, be careful. Use it very sparingly. Too much spraying on the flowers may cause fruits deformed.