Talha bin Ubaydullah reported,

I passed by some people with the Messenger of Allah ﷺ who were atop palm trees. He asked, "What are these people doing?"They replied, "They are pollinating them, placing the male into the female so it becomes pollinated."The Messenger of Allah ﷺ said, "I do not think that accomplishes anything."They were informed of this, so they abandoned the practice. The Messenger of Allah ﷺ was told what had happened, and he said, "If it benefits them, let them do it. I only made a guess, so do not hold me to account for a guess. But when I tell you something from Allah, take hold of it, for I will never lie about Allah ."

عن طلحة بن عبيد الله التيمي قال

مررت مع رسول الله ﷺ بقوم على رؤوس النخل، فقال: ما يصنع هؤلاء؟ فقالوا: يلقحونه، يجعلون الذكر في الأنثى فيتلقح. فقال رسول الله ﷺ: ما أظن يغني ذلك شيئا. قال: فأخبروا بذلك فتركوه. فأخبر رسول الله ﷺ بذلك فقال: إن كان ينفعهم ذلك فليصنعوه. فإني إنما ظننت ظنا فلا تؤاخذوني بالظن. ولكن إذا حدثتكم عن الله شيئا، فخذوا به. فإني لن أكذب على الله عز وجل.