15 minutes is the absolute minimum, and better to give 30 to 45 minutes, if at all possible.
Rinsing the entire roof with the tarps still in place will insure no problems, but takes a lot of time!
A more practical thing to do is, from the ground, rinse the bottom 1/3 of the roof, all the way around, then, after it quits dripping, pull the tarps, and rinse the plants off one last time.
The "secret" to effective rinsing (if you do not have a pressure washer to rinse with) is to use 3/4 inch water hose you buy from Factory Direct Hose Company. It is called "mean green" and is awesome.
I urge every roof cleaner w/o a pressure washer to USE this water hose. 3/4 inch hose will put out
nearly double the GPM of water from a standard water spicket vs 5/8 hose!
3/4 inch Mean Green water hose is light, strong, and a pleasure to use. Buy it guys, it will save your azz, by greatly reducing dead plants, and cut watering time down considerably.
Hold on, I will come back with a chart showing the difference in flow of garden hose!
OK, I am back with the chart, showing the flow differences between various sizes (diameters) of Garden Hose.
3/4 diameter water hose is FAR superior, as can be plainly seen from this chart.
[h=3]What Size Garden Hose is Right For Your Needs?[/h]
Most people don’t give much thought to selecting a new garden hose. They pick one up when their old one splits or when their current garden hose isn’t long enough to reach an area they want to water. Confronted in the hardware aisle with the dozens of styles, types and sizes of garden hoses, most people either buy the hose that’s on sale or opt for a mid-range
garden hose in the length they think they need.
Unfortunately, since they didn’t stop to think about their needs before choosing a replacement water hose, they often end up with yet another hose that doesn’t quite meet their needs and has to be replaced in a year or two. Next time you have to replace or buy a garden hose, take a few minutes to consider your needs and learn how to choose the hose that best meets them.
Diameter
Diameter is an often over-looked factor in choosing the right hose for your needs.
The diameter of the hose determines both the amount of water you can deliver per minute to your destination and the strength of the stream you can direct at it. While there are other factors in determining water pressure – distance traveled and incline, specifically – the diameter of your garden hose is the most important one.
The most commonly bought garden hoses are 5/8 inch in diameter, with ½ inch garden hose and ¾ inch garden hose coming in slightly behind it in popularity. While they may all sound close in size, the performance differences among the three hoses are surprisingly significant.
Just how significant?
The average home water pressure is about 40 pounds per square inch (psi). If you hook up a 25-foot long 5/8 inch water hose, it will put out about 44 gallons of water per minute. A ½ inch garden hose of the same length would only deliver 24 gallons of water per minute while a ¾ inch garden hose would deliver water at the rate of 72 gallons per minute.
In other words,
¾ inch garden hose delivers water three times as fast as a ½ inch garden hose. If your intent is to fill a swimming pool or
garden pond with water, it will fill three times as fast with the wider diameter hose.
Length
Obviously, you want to choose a garden hose that will reach your intended destination, whether it’s your driveway for washing your car or your garden. However, it’s also important to remember that the length of your garden hose will affect the flow rate and water pressure. The longer your hose is, the lower your water flow rate will be. In order to make the best use of water, choose the shortest length of hose to get to your destination.
Next time you need to buy or replace a garden hose, take a few minutes to think about how you’re going to use it so you can be sure to choose the best size garden hose for your needs.
