Hi, such an easy question: Buy some bumble bees.

http://extension.psu.edu/pests/ipm/pestproblemsolver/greenhouse/bugvsbug/bumble

http://www.hydroponics.com.au/issue-88-bumblebees-for-pollination-of-greenhouse-tomato-crops-in-australia/

http://www.ncbi.nlm.nih.gov/pubmed/11332840

Cheers, Nadine

You can improve pollination by agitating the plants. This can be accomplished by wind using fans, or even by simply kicking the benches a few times in the morning after anthesis.

For biological pollination you can try http://www.biobest.be/home/3

For manual, best way is to use special vibrators, for example http://www.brinkman.com/catalogue/tomat/tomat-vario12

Hi to you all and thanks for your great answers. Nadine yes agree that bumble bees are one of the best pollinators for greenhouse tomatoes; however I am in a place which you cannot get a single bumble bee! So, I have to find an alternative way to pollinate the plants.

Hello, if you are not able to get special equipment, I have had great success with "buzzing" plants with electric toothbrushes or electric shavers. They agitate the flowers just like a buzzing bee. It just takes a bit more work.

Dear Binjamin, thanks a lot. Do you think it is an easy way to pollinate 30 greenhouses with a 500 meter square each and around a thousand plants in each greenhouse can be pollinated with electric toothbrushes or electric shavers?

I assume that with so many plants, you must be using a trellis system. Is there a way to shake many plants at once by manipulating the trellis system? It really doesn't take much to get the pollen to fall.

That seems like a lot of plants to do by hand. Jack Haggard seems to have a good idea though, if you don't have enough hands/tools to work with each plant individually. There are a lot of common tools that vibrate (electric sanders for example). If you did have then trellised, you could probably use a bit of creativity to get the job done on a larger scale.

What country are you talking about? Bumblebees can be easily shipped between countries. Although quarantine restrictions may prevent import such as in Australia and various South American Countries. Some preliminary work has been done on alternative native pollinators

Commercial vibrating tools are commonly used in Australia for larger greenhouse operations or the banging and shaking methods described above although these are generally less effective.

One can use air blower on a medium speed may battery operated or electricity operated .one can also use vibrator but it takes lot of time for completing the task.

Apparently a tuning fork works, once you get the right resonance. It's cheap, easy, and requires no power source. I've seen it done, though I have not hung around long enough to see whether the flowers set fruit. Worth a try though!

Thanks Jaboury Ghazoul that is a grate idea!

I had a experience with tomatoes production and in the farm that I worked they used bumble bees for pollination. You can buy a "box of bees". Another option is use a fan for shake the plants, this can help too.

It must have wind or bees for cross-pollination. I think that box of bees is better, cheaper and easier than the use of the big size machine fan or any another machine . May be your place has no bee but you can order from neighboring places. In my country, ordering is very simple.

In Portugal the pollination is well succed with Bombus terrestris hives that may be buied in some enterprises like koppert.

 electricity or battery operated air blowers on a optimum speed  are doing this job perfectly in GH tomato ,it also very less time consuming than all other methods

Here used checking plant by hand or use Vibri vario