Answer: You can take over the pollination process. Lettuce won't need any - you want to harvest before it sends up a flower stalk. If it sends up a flower stalk the leaves will be bitter so harvest your leaf lettuce by pulling the outer leaves off and the center of the plant will continue growing. Or, if you're growing butter lettuce, allow the plant to reach about 6" in diameter and harvest the entire head.
Tomatoes can be pollinated by sharply tapping a branch with open flowers. This will jar the pollen from the male parts of the flower and it will fall down onto the female parts of the flower. A fruit should result. Do this a couple of times a day over a 2-3 day period.
Cucumbers develop both male and female flowers. Males have a straight stem directly behind the flower; females have a slight swelling on the stem behind the flower. Your plant will set lots of male flowers at first and then will set female flowers. Take an opened male flower off the plant and brush the insides of the flower with the inside of the female flower. Pollen will be transferred and a fruit should develop.
Best wishes with your indoor veggie garden!
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