Zakah on products from the earth

Conditions Necessitating Zakah on Grains and Fruits
1- It should be stored goods
If it is not something which is stored, but used for daily consumption, no Zakah is payable on such. This is because the money value of unstored produce cannot be realized due to the inability of benefitting from such financially.

2- It should be measurable in Wasqs

It should be among the products that are usually weighed in Wasqs. Wasqs are units of measure. This is drawn from the Prophet�s statement ﷺ: �There is no Zakah on grains or dates until such items weigh five Wasqs[ One Wasq: Sixty Sa�].� [ Source: Muslim]

If it is not part of that which is usually weighed (in Wasqs) e.g. vegetables and herbs, then Zakah is not due on it.

3- It should be grown for the purpose of cultivation and production on agriculture farms:

However, Zakat is not due on subsistence farms.

4- It should reach the amount of the Nisab,

which is five Wasqs, as evidenced from the Prophet�s statement ﷺ: �There is no Zakah on grains or dates until such items weigh five Wasqs.� [ Source: Muslim] The Nisab in this case is three hundred Prophetic Sa�, which is equivalent to 612kg of good quality wheat. One has to mix variants of the same fruit for the same year in order to see if they add up to the Nisab. For example, sugary dates are mixed with barhi types because they are variants of the same fruit. A different grain/fruit, however, is not mixed with another when calculating the Nisab. Wheat, for instance, is not mixed with barley, nor is barley with dates (and so on).
Source:Islamkingdomzakat