I asked Ibn `Abbas about Salam for (the fruits of) date-palms. He replied "The Prophet (ﷺ) forbade the sale a dates on the trees till they became fit for eating and could be weighed." A man asked what to be weighed (as the dates were still on the trees). Another man sitting beside Ibn `Abbas replied, "Till they are cut and stored." Narrated Abu Al-Bakhtari: I heard Ibn `Abbas (saying) that the Prophet (ﷺ) forbade ... etc. as above.
Sahih al-Bukhari Book 35, Hadith 9
← Previous Hadith as above (446) and said, "We used to pay them in advance for wheat and barley (to be delivered later). Narrated Ash-Shaibani--"And also for oil." Narrated Ash-Shaibani:

who said "We used to pay in advance for wheat barley and dried grapes."

Sahih al-Bukhari Book 35, Hadith 8 Next Hadith → I asked Ibn `Umar about Salam (the fruits of) date-palms. He replied, "The Prophet (ﷺ) forbade the sale of dates till their benefit becomes evident and fit for eating and also the sale of silver (for gold) on credit." I asked Ibn `Abbas about Salam for dates and he replied, "The Prophet (ﷺ) forbade the sale of dates till they were fit for eating and could be estimated."

Sahih al-Bukhari Book 35, Hadith 10