<SEC-DOCUMENT>0001628280-25-040898.txt : 20250820
<SEC-HEADER>0001628280-25-040898.hdr.sgml : 20250820
<ACCEPTANCE-DATETIME>20250820160258
ACCESSION NUMBER:		0001628280-25-040898
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20250818
FILED AS OF DATE:		20250820
DATE AS OF CHANGE:		20250820

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			O'Brien Kevin Patrick
		CENTRAL INDEX KEY:			0001735272
		ORGANIZATION NAME:           	

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-39773
		FILM NUMBER:		251236782

	MAIL ADDRESS:	
		STREET 1:		C/O CPI CARD GROUP INC.
		STREET 2:		10026 W. SAN JUAN WAY, SUITE 200
		CITY:			LITTLETON
		STATE:			CO
		ZIP:			80127

	FORMER NAME:	
		FORMER CONFORMED NAME:	OBrien Kevin Patrick
		DATE OF NAME CHANGE:	20180322

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			HYDROFARM HOLDINGS GROUP, INC.
		CENTRAL INDEX KEY:			0001695295
		STANDARD INDUSTRIAL CLASSIFICATION:	WHOLESALE-MISCELLANEOUS NONDURABLE GOODS [5190]
		ORGANIZATION NAME:           	07 Trade & Services
		EIN:				814895761
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		1510 MAIN STREET
		CITY:			SHOEMAKERSVILLE
		STATE:			PA
		ZIP:			19555
		BUSINESS PHONE:		707-765-9990

	MAIL ADDRESS:	
		STREET 1:		1510 MAIN STREET
		CITY:			SHOEMAKERSVILLE
		STATE:			PA
		ZIP:			19555

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Hydrofarm Holdings Group, Inc.
		DATE OF NAME CHANGE:	20180830

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Innovation Acquisition One Corp
		DATE OF NAME CHANGE:	20170120
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wk-form4_1755720173.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0508</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2025-08-18</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001695295</issuerCik>
        <issuerName>HYDROFARM HOLDINGS GROUP, INC.</issuerName>
        <issuerTradingSymbol>HYFM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001735272</rptOwnerCik>
            <rptOwnerName>O'Brien Kevin Patrick</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1510 MAIN STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SHOEMAKERSVILLE</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19555</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <aff10b5One>0</aff10b5One>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, $0.0001 par value per share</value>
            </securityTitle>
            <transactionDate>
                <value>2025-08-18</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>F</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>48</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.51</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14372</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Shares withheld to satisfy tax withholding obligation applicable to the vesting of 166 stock-settled restricted stock units, which may be settled, on a 1-for-1 basis, only in shares of common stock. Fractional amounts have been rounded to the nearest whole number.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kevin Patrick O'Brien</signatureName>
        <signatureDate>2025-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
