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

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-24</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001316644</issuerCik>
        <issuerName>AeroGrow International, Inc.</issuerName>
        <issuerTradingSymbol>AERO.OB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001232118</rptOwnerCik>
            <rptOwnerName>LAZARUS INVESTMENT PARTNERS LLLP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2401 EAST SECOND AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 600</rptOwnerStreet2>
            <rptOwnerCity>DENVER</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80206</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Convertible Note</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.1</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-06-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionTotalValue>
                    <value>500000</value>
                </transactionTotalValue>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-06-24</value>
            </exerciseDate>
            <expirationDate>
                <value>2013-05-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <valueOwnedFollowingTransaction>
                    <value>500000</value>
                </valueOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Warrants</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0.2</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-06-24</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5000000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-06-24</value>
            </exerciseDate>
            <expirationDate>
                <value>2015-05-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5000000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5000000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Reporting Person purchased $500,000 in Units consisting of a $500,000 Convertible Promissory Note, which pays 8% per year, and warrants to purchase 5,000,000 shares of common stock.</footnote>
    </footnotes>

    <remarks>The reported securities are owned directly by Lazarus Investment Partners LLLP, and indirectly by Lazarus Management Company LLC, as investment adviser and general partner of Lazarus Investment Partners LLLP, and Justin B. Borus, as managing member of Lazarus Management Company LLC.  Lazarus Management Company LLC and Justin B. Borus disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein.  This report is filed jointly by Lazarus Investment Partners LLLP, Lazarus Management Company LLC and Justin B. Borus, all of whom may be deemed 10% owners.</remarks>

    <ownerSignature>
        <signatureName>/s/ Justin B. Borus, Managing member of general partner</signatureName>
        <signatureDate>2010-07-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
