This question was answered in the following thread:https://polishforums.com/archives/2005-2009/real-estate/poland-land-purchase-retiree-38956/
Since you hold a Polish passport and I assume you are a Polish citizen, then you can purchase land without any restrictions.
Here is the law for the purchase of land / forest in Poland by a foreigner:
Issuance of permits to entrepreneurs from the European Economic Area (EU plus Iceland, Norway and Lichtenstein)
On 1 May 2004, the general rule whereby a permit is required for purchase by foreigners of real estate or shares in companies which are legal owners or perpetual usufructuaries of real estate ceased to apply to nationals and entrepreneurs residing or established in the territory of the European Economic Area (EEA).
However, the Act provides for derogation in this respect. EEA nationals and entrepreneurs must obtain a permit in case:
* To purchase agricultural and forest land - for 12 years after Poland became a member of the EU (i.e. until 2 May 2016).
However, EEA foreigners will not be required to obtain a permit during this transitory period in the following cases:
To purchase agricultural land situated in:
* The following eight western and northern provinces: Dolnośląskie, Kujawsko-Pomorskie, Lubuskie, Opolskie, Pomorskie, Warmińsko-Mazurskie, Wielkopolskie, Zachodniopomorskie - after the end of the seven year period (in 2012 earliest) since the execution of a lease contract (date of execution must be certified), if during that period they have pursued farming in person on the land concerned and have legally resided in Poland,
* The following eight central are eastern provinces: Lubelskie, £ódzkie, Małopolskie, Mazowieckie, Podkarpackie, Podlaskie, Śląskie, Świętokrzyskie - after the end of the three year period (in 2008 earliest) since the execution of a lease contract (date of execution must be certified), if during that period they have pursued farming in person on the land concerned and have legally resided in Poland
Keep in mind, the two exceptions (2012 & 2008) to the May 2, 2016 rule require that the land in question has already been 'leased by a person that has pursued farming'.
Here is the full source to the law, defining in detail who is a foreigner, the rules, exceptions, and permit process.