Talha bin Ubaydullah reported,

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

عن موسى بن طلحة، عن أبيه 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.