There is no limit on the number of plants a cultivator can grow.
No. The U.S. Department of Justice (DOJ) has the authority to enforce civil and criminal federal laws relating to marijuana possession and use, regardless of state law. Growing, distributing, and/or possessing marijuana in any capacity, except through a federally-approved research program, is a violation of federal law, and no state or local law provides a legal defense to a violation of federal law. In light of current DOJ guidance, however, it may be unlikely that federal authorities would bring civil enforcement actions or criminal investigations and prosecutions against growers/ processors, dispensaries, physicians, seriously ill individuals or caregivers as long as they are acting pursuant to the Act. A memorandum from the DOJ (PDF), dated August 29, 2013, explains the priorities of federal authorities regarding marijuana possession and use, including state medical marijuana programs.
Here are the federal penalties for marijuana plants:Federal Penalties
21 U.S.C. § 841(b)(1)(A)(vii)
1000 kilograms (2204.62 pounds / 1.10231 tons) or more of a mixture or substance containing a detectable amount of marihuana, or 1,000 or more marihuana plants regardless of weight
$10/50 million — 10 years to life in prison
21 U.S.C. § 841(b)(1)(B)(vii)
100 kilograms (220.462 pounds / 0.110231 tons) or more of a mixture or substance containing a detectable amount of marihuana, or 100 or more marihuana plants regardless of weight
$5/25 million — 5 to 40 years in prison
21 U.S.C. § 841(b)(1)(C)
50 to 99 kilograms or 50 to 99 plants
$1/5 million — up to 20 years in prison
21 U.S.C. § 841(b)(1)(D)
less than 50 kilograms of marihuana, except in the case of 50 or more marihuana plants regardless of weight, 10 kilograms of hashish, or one kilogram of hashish oil,
$250,000/$1 million — up to 5 years in prison
21 U.S.C. § 844
Any person who violates this subsection may be sentenced to a term of imprisonment of not more than 1 year, and shall be fined a minimum of $1,000, or both,
except that if he commits such offense after a prior conviction under this subchapter or subchapter II of this chapter, or a prior conviction for any drug, narcotic, or chemical offense chargeable under the law of any State, has become final, he shall be sentenced to a term of imprisonment for not less than 15 days but not more than 2 years, and shall be fined a minimum of $2,500,L
except, further, that if he commits such offense after two or more prior convictions under this subchapter or subchapter II of this chapter, or two or more prior convictions for any drug, narcotic, or chemical offense chargeable under the law of any State, or a combination of two or more such offenses have become final, he shall be sentenced to a term of imprisonment for not less than 90 days but not more than 3 years, and shall be fined a minimum of $5,000.
21 U.S.C. § 844a
(a) In general Any individual who knowingly possesses a controlled substance that is listed in section 841(b)(1)(A) of this title in violation of section 844 of this title in an amount that, as specified by regulation of the Attorney General, is a personal use amount shall be liable to the United States for a civil penalty in an amount not to exceed $10,000 for each such violation.
(b) Income and net assets The income and net assets of an individual shall not be relevant to the determination whether to assess a civil penalty under this section or to prosecute the individual criminally. However, in determining the amount of a penalty under this section, the income and net assets of an individual shall be considered.
(c) Prior conviction A civil penalty may not be assessed under this section if the individual previously was convicted of a Federal or State offense relating to a controlled substance.
(d) Limitation on number of assessments A civil penalty may not be assessed on an individual under this section on more than two separate occasions.
(e) Assessment A civil penalty under this section may be assessed by the Attorney General only by an order made on the record after opportunity for a hearing in accordance with section 554 of title 5. The Attorney General shall provide written notice to the individual who is the subject of the proposed order informing the individual of the opportunity to receive such a hearing with respect to the proposed order. The hearing may be held only if the individual makes a request for the hearing before the expiration of the 30-day period beginning on the date such notice is issued.
Pa. Cons. Stat. Ann. tit. 3 §§ 701 to 710 (Purdon 2016)