Came across a pretty fascinating video from Dr Shaddox regarding a study where watering more frequently led to healthier grass. We've always been told watering more frequently leads to shallower roots, less pest resistance, etc., this study seems to dispute some of that.
There also seem to be many things missing from the study that left more questions than answers for me.
- The study did not include Bermuda grass
- It did not address issues like was fungus more prevalent or would watering only in the morning be sufficient to prevent it
- Was the grass more susceptible to diseases
- Would this make it more susceptible to frost damage if the roots aren't as deep
- Did the increased weed pressure outweigh the benefits of healthier grass
I am a bit conflicted now on if I should water 4x/wk at 0.25" per session or stick with twice a week at 0.5" per session. Of course, from a visual aspect, the grass always looks healthier and greener after getting water, but that doesn't mean the downsides don't outweigh the benefits.
Everything with lawns is a balance... you are dealing with nature and whilst science and studies can be very helpful at times, there are so many variables and qualifications to be made that you can get caught up with mostly irrelevant studies and overthink these things.
My thoughts are that observation/ personal experience with your lawn in your locale and common sense should prevail.
Once a lawn is established, a combination of deep and shallow waterings are necessary...shallow watering means you use less water and nutrients remain in the profile for longer, ( more important in sand) but have to irrigate more often in the warmer months. Shallow watering means the plant does not have to work as hard, competing against gravity and air pressure to lift and extract moisture from the profile. This means that generally speaking, the plant should be healthier, having to work less.
We all know that Deep water encourages deep roots for those dry times, especially with bermudas where I have seen rhizomes down at 4 feet many, many times. However, Irrigation water moving past the principal root zone is wasted water as gravity continues to pull it along with various nutrients downwards.
Various Fungal diseases are only relevant at certain temps and more so with some specialist varieties so you should be able to ascertain that and manage accordingly. Thatch build up and heavy nitrogen use will be contributing factors as well.
With frost, I cannot imagine the level of frost damage being dependent on root depth....Frost is the freezing of the moisture in the leaves, rupturing the cells.... if your soil is not being frozen then there is no issue with roots...Recovery from frost will obviously be quicker on an established, well maintained, healthy lawn but with bermuda, its so tough, that frost should never be an issue (other than short term visually). High nitrogen levels will make for softer weaker leaves with higher moisture levels that will be more susceptible to frost damage. Lower mowing will potentially lower the overnight soil temps, as there is less buffering against the cold night air. Lower soil temps equals slower recovery.
Regarding weeds, a thick healthy lawn should remain close to 100% weed free all the time, however if you are mowing very low, then you are providing more opportunity for new weed to germinate and establish... at the same time the increased mowing frequency necessary for low mowed lawns will take out most weed as it germinates/early stages of development meaning only the weeds with the very lowest profiles/height tolerance are likely to establish. Constant moisture in the upper profile will also encourage germination and potential fungal issues.
Weeds in Bermuda are so easily controlled these days, that IMO, it really shouldn't be a concerning factor.
Just my thoughts..
Cheers.
