Following article https://www.financialexpress.com/archive/cultivating-tax-free-income/47843/ mentions that
"If you grow flowers even in cities and towns on small plots of land, like in the compound of your house or even on a large terrace in earthen or plastic pots and you genuinely carry on this activity, the income would be treated as agricultural income and cannot be taxed."
Also refer this answer: https://www.quora.com/Is-agricultural-income-from-non-agricultural-land-exempt-from-income-tax/answer/Jagdish-Handa
Also Section 2(1A) of Income Tax Act which defines "agricultural income" does not restrict income from cultivation at home premises from the purview of "agricultural income" .