Praise be to Allah.
In the case of palm trees growing in people’s houses (gardens), zakaah is due on their fruits if it reaches the nisaab, because Allaah says (interpretation of the meaning):
“O you who believe! Spend of the good things which you have (legally) earned, and of that which We have produced from the earth for you” [al-Baqarah 2:267]. This is one of the things that Allaah produces from the earth for us, so zakaah is obligatory on it whether it is given as gifts, eaten or sold.
If it does not reach the amount of the nisaab, there is no zakaah due on it, because the Prophet (peace and blessings of Allaah be upon him) said: “No sadaqah (i.e., zakaah) is due on anything less than five wasq of dates.” A wasq is sixty saa’ of the Prophet (peace and blessings of Allaah be upon him), and the saa’ of the Prophet (peace and blessings of Allaah be upon him) is equivalent to 2.4 kilograms. So the nisaab is 612 kilograms. The standard in this case is the weight of good quality wheat; 2.4 kilograms of good quality wheat should be put in a vessel, and the goods to be assessed should be of the same volume as this, no more and no less. This is the saa’ of the Prophet (peace and blessings of Allaah be upon him): to measure goods other than wheat by volume.
It is well known that things to be measured by volume may vary in weight; if it is heavy then the zakaah should be increased accordingly.
The rate of zakaah is one-half of one-tenth [i.e., one twentieth, 1/20] because it is irrigated with water which is brought from wells or the sea, but there is effort and cost involved in pumping or desalinating the water. The Prophet (peace and blessings of Allaah be upon him) said: “For things which are watered by rain or springs, the zakaah is one-tenth; for things which are watered by bringing water to them, the rate is half of one-tenth.” (Narrated by al-Bukhaari).
There is no zakaah on the seedlings, but if they are sold for cash and the money is kept for an entire (hijri) year, then zakaah becomes due on it.
There is no zakaah on the palm-tree which is planted for the purpose of obtaining seedlings, just as there is no zakaah on the palm-tree which is planted for the purpose of selling its fruits. Whatever fruit of domestic palm trees is sold, zakaah should be paid on its value. Whatever dates are eaten fresh, zakaah should be paid in fresh dates of intermediate quality, if they are plentiful, and whatever dates are kept and dried, their zakaah should be paid in dried dates. And Allaah knows best.