A "grow house" blends in with all the other houses on the block and in the neighborhood, because the outside looks just like all the other houses around it. But on the inside, marijuana is growing illegally under special lights. A criminal can set up a grow house in any neighborhood, but usually chooses upscale areas. There are some things to look for that will help you spot a grow house.
You may notice unusual wires running from power lines to the house. Grow houses need more than a normal family's share of energy. To avoid detection by the power company, the house is frequently illegally wired to the utility lines. Or, you may hear the sound of generators inside the house, providing the extra electricity needed.
Because the grow lights are on day and night, all the windows of a grow house may be covered with thick fabric or another material that blocks out light, so the neighbors won't notice the lights on all night. Or, you may see beautiful blinds and drapes in the windows, but they're always closed. This doesn't automatically make it a grow house -- it's just another thing to look for.
If you become suspicious of a nearby house, without obviously monitoring the comings and goings of the folks who live there, note if their behavior isn't typical. Do they never carry groceries into the house? Do they never carry groceries into the house? Does it appear that no one actually lives in the house, but come over for short periods of time? Do the people you do see avoid interacting with their neighbors? Do they seem to not have an obvious job schedule, but still drive expensive, fancy cars?
Notice if structural changes have been made to the house, like extra air vents. Have added security features been made, such as bars on the windows, a new privacy fence or a guard dog in the yard?
Do the house and yard seem neglected in general? Is the lawn mowed regularly, snow removed in winter and trash put out at regular intervals? Do advertising flyers and junk mail accumulate outside? You may see pots and bags of potting soil and fertilizer stacked around the back, yet the landscaping does not give the appearance of being tended by anyone interested in gardening.
Sometimes a grow house actually has people living in it, and you will see regular, normal behavior from these people. However, often just one room or a backyard shed is used to grow the marijuana. Notice if the lights are on day and night in just one room, or if electrical cords and water hoses run to a shed.
When the wind is blowing from the direction of the suspected house, or when you walk past, do you notice any obvious smell?