Triplex- Raise rents??

[Hank Parater]

Just bought my first triplex!

Currently the renters are paying $300 under market, and they are on month to month verbal agreements- no signed lease. The renters have been there for 3 years, and keep they're places very tidy. No kids, no pets. One lady even pays rent a week ahead. 

So, I have a dilemma: I'd like to raise rents, but don't want them packing up and leaving right away, especially going into winter. Not trying to have vacant property through winter. Also, I will be living in one unit, so I have to see and interact with them probably daily. So, my thinking is this: wait until march then hike it up- if they leave, then oh well, I will have better luck finding tenants in spring. Or maybe, just hike it $100 starting in november, and have them sign a 6 mo lease- that way when I raise another 200 in 6 months its not such a shock.  But knowing that I'm losing basically $600 per month burns at me. What do you think BP Nation??