Any ideas on how to retrofit a non-wif Orbit irrigation controller?

Before I decided to go the home control route for my secondary residence in AZ, I had the irrigation system rebuilt including a now one year old Orbit 4-station model #57894 irrigation control unit. I have two zones (front and back). The problem is we are there sporadically. In addition, I had two new citrus trees planted last spring when I added the new irrigation system, and the tree guy who planted them indicated that I should really cut back on the water in the winter (less hot in the Tucson area, and they get most of their moisture that time of year) because the ‘excess’ moisture is bad for the citrus trees specifically. So in the winter, I should water only once a week, and from the middle spring through the mid fall, I should water 2-3 times per week. However, I am often not there to make this adjustment to my system. I can have the landscape guy who comes once a month make the adjustment, but would like having remote control of this. This last March I put in a Vera Plus into the house, which I use to control locks, lights and motion sensors in the house. The irrigation controller is outside but probably within 20 ft of the Vera Plus and the router-modem and less than 5 ft from a repeating lamp module.

Is there any inexpensive way to convert the Orbit controller or should I just bite the bullet and purchase a new wifi/z-wave irrigation control unit? Depending on the cost, I might just rely on the landscape guy. Thanks for any help.