For quite some time now, I’ve been recommending wetting agents on new sod installations to obtain quicker and more thorough rooting. Intuitively it should work, and I’ve seen good results as well. But I’ve never seen it demonstrated side by side with untreated sod. So this summer, I put on my product development hat and decided to do a test plot with a couple of wetting agents and a moisture-holding product.

The test was started on June 14, 2021 and consisted of 4 pieces of bluegrass sod, each 2’ x 5’ in dimension.

Day 0

Treatments were, from left to right:

  1. Hydretain Granular OC at 3 lb / 1000 sq. ft.
  2. Vivax 10G at 3.5 lb / 1000 sq. ft
  3. Untreated
  4. Cascade G 0-0-20 at 5 lb / 1000 sq. ft.

All rates were from the product labels. Right after application, all plots received 0.25 inches of irrigation. Irrigation was initially kept to 0.25 inches every other day to really challenge the sod. It became apparent that 0.25 inches per irrigation weren’t going to cut it with temperatures in the 90s. I upped the irrigation to 0.5 inches, and then it also rained.

Day 8

On day 8, you can see the plots had been severely stressed even though they had received 2.75 inches of rain/irrigation by that time. However, you can see the Vivax treatment showing a better regrow than the other plots. 

Day 23

On day 23, the picture shows more regrowth on all the plots with Vivax still showing a little better. The plots had an additional 4.125 inches of rain and irrigation since day 8.

I developed a method to measure rooting by clamping boards with nails in them to the edge of the sod and then attached a scale and rope to determine the maximum lbs of force needed to pull up the sod. On Day 39, all plots were pulled up. See videos below of how each plot performed.

It was clear that the Vivax treatment had the best rooting and took 55 lbs to pull it up, and it did not rip.

Cascade also did not rip when pulled, but it took 53 lbs of force, and its rooting was not quite as good as Vivax.

The untreated took 49 lbs of force to pull, and it ripped. Rooting was not very extensive.

Hydretain also ripped when pulled with 40 lbs of force. Rooting was also not very apparent.

In conclusion, the use of wetting agents does improve sod establishment. The ability to get water to penetrate the sod and into the soil below helps roots search out that moisture and root into the ground. There is also a moisture-holding component to it, and of course, that will help as well.