I have 5 Kalanchoes in my balcony and they are faced to the east, and they get around 5 hours (7 am to 12 pm) of sunlight. But recently the flowers' color started to fade out and then after a while they got completely dried out and fell off.
I live in a dry city and the temperature varies between 25 to 15 degrees C. It's also so windy around here most of the time.
Could it be the soil, watering, etc.? Or it's just their natural behavior?
From what we can see of the leaves most of them look good, except for one or two a bit singed on the tips. This could mean not quite enough watering perhaps during a particularly dry and windy spell, but that is minor. It is normal for the flowers to emerge in profusion and then die off; the plant then goes into a recovery phase where it is nothing but leaves for a while, and then repeats flowering.
Kalanchoe sounds like a good choice for your location. As a succulent it is designed to soak up water like a sponge and then release the water as the plant needs it from root, stem and leaves. When this sponge is fully saturated after a rain or watering hold off on the water to ensure that the roots have the opportunity to breathe.
Many flower end-customers purchase flowers when they are in full bloom since then they are sure of getting a very good specimen since all the flowers are out. However the wise buyer waits for the opportunity to get plants which have just started flowering and show lots of healthy flower buds. This way you can be sure of the colour and will enjoy the full maximum flowering for the longest period of time as the potential buds start emerging in their turn.
