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I was reading the “Cultural Aspects of Disease Management” chapter in Management of Turfgrass Diseases by Dr. Vargas and came across this gem about soil pH: “Most of the literature tells you that the soil pH should be maintained at the optimum level for turfgrass growth (between 6 and 7).

The N-only pot looked pretty good when I showed roots after 184 days. But that same grass grew a lot more, and produced a lot more underground roots and rhizomes, when P and K were added.

Regular readers of this site will remember the grow-in experiment I started on 1 October 2019. I wrote about it in these posts. Fertilizer response at planting Experiment update: fertilizer response at planting

Ben Kebby has started a Facebook group, Tuesday Evening Research Papers, or T.E.R.P.S. He shared this week an article I wrote in 2012 about understanding turfgrass nutrient requirements. I tried to write a 1 page update or overview to elaborate on that, but it spilled over to 2 pages.

This photo was taken 174 days after the ‘Tifeagle’ bermudagrass and ‘Wana’ manilagrass were planted as 3 cm diameter plugs on 1 October 2019. These particular pots have been fertilized with nitrogen only since then, with no P or K.

There’s an interesting article by Espevig et al. on Effects of rolling and N-fertilization on dollar spot and Microdochium patch on golf greens in Scandinavia. rolling a red fescue green two times a week reduced dollar spot by 61% compared to no rolling rolling four times a week reduced dollar spot by 95% increasing annual N on a creeping bentgrass + Poa annua green from 15 to 24 g/m2 reduced dollar spot by 24% but the following spring saw twice as much Microdochium patch on the plots which received the higher N rate There are a number of surface performance benefits that come from rolling, and disease suppression is one of them.

A few years ago Blake Meentemeyer and Brian Whitlark wrote about fertilizer in the Green Section Record. I’ve recommended this article before, and in that post I highlighted a case study from the article—a “facility in the Las Vegas area” reduced putting green fertilizer cost by a staggering 82%.

I had a great email exchange last December. It gets at what is really required, in a couple key areas, to produce high quality surfaces. And that might be less than you think.

I almost always recommend keeping the soil pH above 5.5. This minimizes soluble aluminum in the soil, which can be toxic to roots. Get the soil pH above 5.5, and the soluble aluminum won’t be very soluble anymore—it drops almost to 0.

The PPFD (photosynthetic photon flux density) every 5 minutes for a day, week, month, and year at Corvallis looks like this. I’m not so interested in the PPFD when the temperatures are too cold or too hot for photosynthesis.