Pretty day

[malaka]

Woke up to a beautiful morning; sunshine peeked through the trees from a pure blue sky. Sat down in my office and looked out my front window, and there she was again, enjoying the nectar from my blooming hosta.

Comments

warning this is long!

[a1]

what you're interested in is the ETo (evapotranspiration: soil evaporation and plant transpiration) column. This is your water demand based on the weather (air temp, humidity, solar radiation, wind, rainfall, etc.).

I just looked at the sum at the bottom of the column, which is 4.31 inches (for the last 14 days). This is the number you adjust for your warm season grass - the normal adjustment is 60%.

However, what you can do is look at the data from the last time you irrigated and sum up the ETo to determine what your water demand is and then adjust it for the 60%. But in order to determine how long to run your irrigation, you need to know what your precipitation rate is. Typical homelawn irrigation systems put out around 0.5 inches per hour.

So if you last irrigated on the 10th, your demand would be 1.2 inches (0.41 + 0.41 + 0.38). Adjusted value is 0.72 inches. 0.72 x 60 (conversion from hrs to mins) / 0.50 (precip rate) is 86 minutes. Of course, you don't want to put all that down at once. You can do several cycles - say if you do 3 cycles during the night/morning it would be 29 mins a cycle - you can run the cycles a few hours apart to make sure all the water soaks in.

Does that make sense?

How much do you irrigate now?