Why do my dragon fruit flowers turn yellow and fall off and what to do about it

Since I started getting flower buds from my dragon fruit I decided to do my research on how to increase the chances of the flower buds to develop into fruits. I found out that there are two main types of dragon fruit when it comes to development of fruits from flowers. The first one is the fertile type which means it doesn't need hand pollination or cross pollination to set fruit. Some growers also call this the "self pollinating" type. The other type is the sterile or non-self pollinating. This type needs cross pollination from a fertile type in order to set fruit. If you only have this sterile type of dragon fruit in your garden, there is no amount of hand pollination that you can do to have your flowers developing into fruits. So if you have a plant that is 2 to 3 years old producing flowers but the flowers after blooming just fall off and never end up developing into fruits, then chances are you have the sterile type. Now what you can do in this situation is to plant a known fertile type so you can do cross pollination. To ensure that you get fruits from your plants, only plant known fertile type dragon fruits in your garden. You can also increase the size/yield of the fruits by planting two known fertile types together in one post/trellis side by side (increase chances of cross pollination by doing this). Dragon fruits growers do this in their farms to get better fruit yield. Cheers.