TURF TIP
7/22/03

Summer Putting Green Cultivation

The peak golfing season is in full swing. For many clubs this means that it is tournament time! This also means elevated expectations from members for “fast” greens. Most managers are mowing low and rolling on a regular basis to meet these demands. While these practices are great for green speeds they are not exactly what the doctor ordered for the turf plant, especially this summer.

It seems Central Indiana has not been able to catch a break in terms of consistent dry weather. The deluge of rain that began on the 4th of July has finally begun to dissipate but the frequent afternoon and morning thundershowers continue to plague us. This means the upper ½ to 1 inch of the rootzone is staying overly wet if not saturated. With day-time air temperatures remaining in the mid to upper 80’s that probably means the soil temperatures in the top 2-3 inches are probably about the same, not ideal for bentgrass or Poa annua. Foot traffic, frequent mowing and rolling traffic all provide significant compactive forces especially on these wet soils and oxygen diffusion rates into the rootzone are probably declining rapidly. To add fuel to the fire the wet thatch layer is causing an increase in moss and algae incidence. The sum of these factors is that the surface layer of many greens may be or is becoming sealed off. Some managers have also noticed the dreaded “black-layer” appearing. A sure sign of anoxic or oxygen deprived soils.

At times like this it may be time to consider supplemental summer cultivation, in the form of spiking or light aerification. This will encourage drying and improve oxygen diffusion, ultimately helping root systems breathe. Some suggestions for summer cultivation: include regular light spiking (5 to 7 days apart), solid, cross or star tine aeration or in severe cases a shallow (1/2-1 inch depth) hollow tine aeration. Regardless of what you choose, be mindful of the relatively shallow root system many plants have right now. Some areas may not tolerate the mechanical action imposed by an aerifier and a walking-behind garden spiker may be more appropriate for very weak areas. If you decide on hollow tine cultivation, which will physically remove a portion of the black layer, make sure the tines used are 3/8 inch diameter or less (1/4 inch would be preferred). This will ensure that the holes heal back as quickly as possible. Do not drag the cores back into the green, blow them off to the edge of the green and haul them away. The excess sand abrasion from dragging cores can inflict severe mechanical injury on an already weak plant. Furthermore, make sure you LIGHTLY roll any areas that were aerified prior to the next mowing to minimize any scalping that may occur due to raised aerification holes or spiked areas. If you are rolling greens to maintain or increase green speed, avoid low, wet areas on greens and stay away from any areas that have significant algae.

Summer can be a difficult time, especially when important member-guest tournaments or club championships are being played at a time when the putting greens really just need a break. Keep the lines of communication regarding these unscheduled supplemental cultural practices which affect putting quality and ball roll. Nobody likes big surprises! Let your facility management, greens committee, etc. know what you are doing and why. But ultimately continue to provide the best possible playing conditions possible. Do not let the hot, wet, stinky soils of July get you or your turf down!

 Cale Bigelow, Assistant Professor of Turfgrass Science

Send corrections, suggestions, and comments to biehlj@purdue.edu