“This is contractual uncertainty: how can he buy something he cannot see?”
His explicitly recorded position is that he does not permit the sale of cucumbers of both kinds, eggplants, and similar crops except one picking at a time. Of the produce in cucumber and melon plots, only what has appeared may be sold, not what remains concealed. Green fodder may likewise be sold only one cutting at a time. This accords with the position of Abū Hanīfah and al-Shāfiʿī, because such a sale involves contractual uncertainty and constitutes selling fruit before its soundness becomes apparent.
His followers then differed. Most applied this ruling without qualification to everything concealed underground, such as carrots, radishes, onions, and similar produce, in agreement with al-Shāfiʿī and Abū Hanīfah.
Shaykh Abū Muhammad said:
If both the above-ground growth and the roots are sought, as with onions sold green, leeks, and radishes, or if the above-ground growth alone is sought, the preferable view is that its sale is permissible, because the intended part is visible. It thus resembles trees and walls, with the unseen portion included in the sale as a subordinate element. If, however, the roots are the principal object sought, selling it while it remains in the ground is impermissible, because the ruling follows the predominant element. If the two are equally sought, the sale is also impermissible, because the basic rule is that the condition must be observed; it is waived only for the lesser, subordinate portion.
Ahmad’s wording admits of two interpretations, for Abū Dāwūd said:
I asked Ahmad, “What about selling carrots while they are still in the ground?”
He replied, “Only those that have been uprooted may be sold. This is contractual uncertainty: how can he buy something he cannot see?”
Thus, he based the ruling on the lack of sight of the item.
It may therefore be said: unless the whole of it has been seen, it may not be sold.
Alternatively, it may be said: seeing part of the item being sold is sufficient when it indicates what the rest is like