Strange plant grow - thin and spindly

I can tell you its most likely because you're growing without any nutrients. The lack of nitrogen has caused this long spindly growth and light green leaves. The lack of phosphorus and potassium is why your flowers are small and the outcome is going to be very poor. To prevent this next time I strongly advise you use a nutrient regiment or a living soil if you only want to water your plants. You might be able to help them now by giving them a light bloom feed but with autos you want to go half strength. I hope this helped.