<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-01-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001807707</issuerCik>
        <issuerName>AppHarvest, Inc.</issuerName>
        <issuerTradingSymbol>APPH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001605182</rptOwnerCik>
            <rptOwnerName>Lee David J.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O APPHARVEST, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>401 W. MAIN STREET, SUITE 321</rptOwnerStreet2>
            <rptOwnerCity>LEXINGTON</rptOwnerCity>
            <rptOwnerState>KY</rptOwnerState>
            <rptOwnerZipCode>40507</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2021-01-29</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>215040</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>215040</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The security represents restricted stock units (&quot;RSUs&quot;) granted to the Reporting Person. Each restricted stock unit represents a contingent right to receive one share of common stock of the Issuer.</footnote>
        <footnote id="F2">These RSUs will vest and become exercisable in 12 equal quarterly installments commencing July 24, 2020, subject to the Reporting Person's continuous service with the Issuer on each such vesting date.</footnote>
        <footnote id="F3">Received pursuant to the Business Combination Agreement and Plan of Reorganization, dated as of September 28, 2020, by and among Novus Capital Corporation (&quot;Novus&quot;), ORGA Inc., a direct, wholly-owned subsidiary of Novus (&quot;Merger Sub&quot;), and AppHarvest Operations, Inc. (f/k/a AppHarvest, Inc.)(&quot;Legacy AppHarvest&quot;) pursuant to which, through a merger between Legacy AppHarvest and Merger Sub, Legacy AppHarvest became a direct, wholly-owned subsidiary of Novus, which subsequently changed its name to AppHarvest, Inc. (the &quot;Issuer&quot;).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Katie Kazem, Attorney-in-Fact</signatureName>
        <signatureDate>2021-02-01</signatureDate>
    </ownerSignature>
</ownershipDocument>
