Beginner Gardening: Watering question, 1 by Diana_K

Diana_K wrote:
Soaker or drip irrigation concepts: Water is applied slowly, and at the surface of the soil. Almost none is lost to evaporation or run off, it all (99%+) soaks in.

1) What kind of soil do you have?
Sand: Water will race pretty much straight down. Very little sideways movement at all. You can use tubing with a faster application of water.
Silt: Water won't actually puddle, but there will be some sideways movement. A middle rate of application will work, but the fastest watering could cause puddles.
Clay: Even a slow irrigation method can cause puddling, and a lot more sideways movement- Once it begins to puddle it is soaking straight down, not just under the emitter, but the whole puddle area. If you are drip irrigating a hillside, the plants may need berms to hold the water to give it time to soak in. Slower application method is best.
A really well prepared soil with plenty of organic matter, plenty of air spaces between the particles: Probably won't see puddling, but you will highly likely see better sideways movement.
If the water puddles, but still soaks into the target area, that is OK. But if the puddles spread farther, and are not actually watering the plants then you need to adjust something: Tubing location, emitter rate, or how long it is running. Sometimes more complex solutions are needed.

2) How deep does it get?
Best is to test it. Water an area that is as much like the planted area as possible, but you can dig up. Water for whatever set amount of time you want, then let it sit an hour (perhaps more in clay soil) then go dig a hole and see where the water went. How deep? How wide?

3) Here is the million dollar question:
Did it wet the root zone of the plants you are growing?
a) Yes- Then that is how long to run it.
b) No, it did not go deep enough- Then run it longer, or add another line pretty close.
c) No, it did not move sideways enough- Then run another line over the area that is the most dry.
d) In some areas it is great, in others it needs more water- Then add more line in the drier areas- Widely separated line = more water at the surface, wider spread of the water (strawberries, lettuce... shallow rooted plants). Closer placement of the line = coverage will overlap, and go deeper. (Tomatoes, Melons, other large plants with deeper roots)

4) Simple helpers:
A surfactant can help the water soak into the soil. They have names like Water Wet, or Water In, but liquid dish soap (for washing dishes by hand) can be added to the water at the rate of 1 tablespoon per gallon. Soak the surface, then run the irrigation to further dilute it and deep soak the area.
A watering tube is more for large trees- it is a vertical pipe with holes, filled with coarse rock. Fill the pipe with water, and it can soak deeper, faster.