Growing cannabis will leave an odor in the house. The plants are oily. As Shawn Davis had stated, remediation would be needed.
"a landlord can prohibit renters from growing pot by including the rule as a clause in the lease. If the issue comes up after the lease has been signed without such a clause, the landlord would likely need to rely on an anti-drug or crime policy that hopefully was included in the lease.
The landlord would then need to send written notice of the lease breach, citing the appropriate clause. If the renter continues to grow plants after receiving the written notice, the landlord may attempt to evict the tenant." - Zillow.com
If you don't allow smoking, would you allow the consumption of edibles and oils? The bigger and more important issue is with the growing and/or smoking of cannabis.
Can you discriminate? Yes. Just put a clause into the agreement. Something to prohibit smoking and an anti-crime and drug clause.
But 'should' you discriminate against the growing of cannabis in your rental? In most cases, that would strictly be a 'business' decision. Just like allowing a pet, add a premium to your rent. In your case, you and your wife plan to move into it after your child graduates from high school. In addition to the odor that is left behind, your new neighbors will also carry an opinion regarding how the landlords allowed their tenants to grow cannabis. Like it or not, the tenants may leave an impression about the type of people they signed a rental agreement with.
What about federal laws about cannabis? The 9th U.S. Circuit Court of Appeals in S.F. banned the Justice Department from prosecuting MMJ cases if no state laws were broken. The state of Colorado protects us from federal meddling. As long as we obey our state laws.
Final point: a Real Estate attorney to can modify your rental agreement. With that being said, I am not an attorney and am in no way giving legal advice. Have a great Labor Day weekend!