Please give me your opinions...
What watering will produce the best root formation..
Deep soaking or shallow watering for deep roots on grass and trees?
Roots follow water.
Definitely deep watering infrequently! The idea is that you want the water to soak in deep, forcing the roots to likewise have to go deep to get the water. If you water frequently and shallowly, the roots never have to go down deep to get water.
For a lawn, set up little tuna cans around the lawn. Water until the tuna cans have filled up -- about one inch of water is what you want. Take a note as to how long it took the cans to fill up this long, and that is how long you need to water.
Depending on your climate, you may be able to get away with watering only once a week. Try waiting four-to-five days. If the lawn still looks good, then you're fine. If it's seriously wilting, then you'll need to go twice a week. You really shouldn't have to water more than twice a week in nearly any climate.
For established trees and shrubs, you shouldn't have to water more than once a week at most. I get away with once a month. Basically, use a soaker hose, and let it go for a number of hours. You want the water to go very deep.
Deep root watering is correct. If you can for your trees especially, use the deep root watering/fertilizing probes for watering your trees..that is unless you have a forest..LOL... Your trees will love you for it. it puts the water down deeper and the roots follow the water which also makes them go downwards as well. Shallow watering is NOT the way to go. It spoils the roots and then if it does get dry and you can't water, it is very hard on the plants, lawns and trees and sometimes fatal.
Only not frequent, deep watering! As always, with exceptions - there are plants that from their nature will not develop deep roots. Heathers are among them. Rododendrons as well. They need more frequent and not so abundant watering
We are discussing developing roots for drought tolerance, in plants that have a chance at surviving one.
I garden in the PNW as well as in the desert. In the PNW, rhodies are amazingly drought-tolerant. Although the winters are very wet and cool, summers are very dry, like a mediterranean climate. During the wet part of the year, the rhodies (and other plants) establish a good root system. Although relatively shallow-rooted, I've had mature rhodies go over a month with no supplemental water when plants all around them were wilting. They got pretty ratty looking, but perked back up when the fall rains came. On the SW Washington coast, because the sand won't hold water, drought-tolerance was a must for my plants. Although the water supply was plentiful (in my area but not all parts of the PNW), nobody wants to have to water more frequently than necessary.
GPB's posting is most interesting. I wish the video had a voice over to give measurement of the fittings for the 2 liter plastic bottles used. Meanwhile hope that one of you can come up with a list of what is used. I have a very large sloped ornamental garden and have difficulties getting enough water to the root systems w/o using an inordinate amount of water.
Will definitely be following this thread.
Rosie, Sugar Hill, GA
This drought we are having is teaching me some things. I have be a strong advocate of drip system irrigation for quite some time. What I am finding out is that sometimes the drip is not as effective as it once was. On top of the lack of rain the temps have had a detrimental effect. Then to top it off the wind has been double the normal speed. The effects of evapotranspiration has been devastating. One of the things that has helped is a good soaking with the old sprinklers once in a while. I think what may be happening is that with normal rainfall there are roots in places that do not normally get water with the drip. So during drought these roots get nothing and the plant simply cannot take in enough water to sustain the top growth. This is just in theory, but it has helped.
Adding in my own expertise here, if you were to add some external source of electricity to the plants or soil, it can help with increasing root mass and also potentially help with drought resistance too, through making the cell walls less permeable.
If you were to do this, you should still probably do deep watering, infrequently. This will probably help you go for longer periods without water.