# Watering deeply and root growth



## behrygood1982 (Oct 23, 2020)

Hey,

I understand that watering deeply and infrequently is recommended since it helps the roots grow. How does this actually work though?

1. Do roots only travel further into the ground when they are following water? For example, if the first 1-2 inches of soil is dry ( and also the bottom 2-6 inches ) will the roots start diving down to look for more water OR do they only dive down looking for more water if there is water there and it knows it should follow it?

2. If i water deeply and the soil is wet from 1-6 inches is this ideal or is it ideal that after a deep watering the top of the soil has absorbed the water and most of it has drained down deep and is sitting there? For Example, after a watering if it took a core in best care scenario would it be better if it was wetter deeper down vs. wetter at the top?


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## BadDogPSD (Jul 9, 2020)

The roots will seek water. If you water shallow, the water stays towards the surface and the roots have no need to go deep.
You need to water more frequently because the top 1-2 inches will dry quickly.
If you water longer to get the water deeper into the soil (around 6 inches) and then don't water for several days, the roots will seek the water that is deeper in the soil. It takes longer for the deeper soil to try out.


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## Delmarva Keith (May 12, 2018)

My understanding of plant root growth is a little different. Plant roots do not seek water. There is no intelligence in roots. Plant roots grow in response to a need for water and nutrients. Roots will not grow if they are dry but will grow if in an area of adequate moisture if he plant needs more water or nutrients. So it looks like they are seeking water but what's really going on is the existing moisture is triggering the growth, while very dry inhibits that growth. They just keep growing where it's adequately wet.

Roots also grow more if even through the plant is getting "adequate" water the plant needs nutrients. Plants take up nutrients with the water. I forget all the ion transfer and all that jazz but without water to transfer the stuff to the plant, no nutrient uptake without moisture.

Frequent shallow watering leads to a shorter, shallower root system. The plant gets what it needs with shorter, shallower roots. Deep watering at less frequent intervals that allow the surface soil to dry a bit forces the plant to grow deeper and more extensive roots to get what it needs. The roots just continue to grow into moist soil to get what the plant needs.

That's my understanding. So to your question, if a plant were placed in soil of some but inadequate moisture with a dry soil barrier between the plant and moist soil somewhere deeper (maybe like a layer of several inches of dry sand or something that just drys out super fast and doesn't wick water in the soil profile), I'd predict the plant would die because the roots will not grow through the bone dry layer no matter how much water is underneath. I've never done this to see one way or the other but I think that's how it works.


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## g-man (Jun 15, 2017)

^+1

Also, read the ET and Irrigation guide for more details on how the whole water/moisture is managed.


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## behrygood1982 (Oct 23, 2020)

Thanks everyone for the feedback. Was very helpful


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