How to Introduce 007 Creeping Bentgrass Into Older Varieties of Bentgrass?

I often am asked the question of "What is the best way to introduce new varieties of bentgrass into older varieties" (i.e., Penncross).

Interseeding new varieties of bentgrass will not solve poor drainage, poor air circulation, low light intensity, poor watering practices and other maintenance issues.  If any of these factors are limiting the potential turf quality of a green, you MUST first solve these problems before you can expect significant improvement to the turf. 

Let's first discuss timing of the introduction of seed into an existing green, tee, or fairway. 

The best time of the year to spike and seed is the months of June, July and August.  My suggestion is to spike and seed every other week starting in early June and continue through to August. 

The seeding rate should be in the range of 0.25 lb / 1,000 square feet (1.25 gram / meter square) every other week.

The spiking should be with the use of a "Job Saver" or "Speed Seeder" seeder with "cone shaped" spikes that penitrate approximately one to one and one half inch deep. 

If you do not have a piece of equipment like the one shown above there are many makes and models of spiking equipment that can produce a small hole in the surface for seed to fall.

When interseeding greens I suggest applying a light application of topdressing to the surface (after seeding)and brush the sand into the thatch / mat.

Adding a new improved variety of creeping bentgrass (i.e., 007) will add to the seed bank and gradually incorporate the new genetics into the turf stand.  

You can expect that after two to three years of interseeding 007 into a Penncross green the turf will show the qualities (i.e., over all density and texture) of the new variety.  That is not to say that all of the Penncross will be crowded out as I expect that some Penncross will remain.  What I do anticipate is that the new 007 will become the dominant grass on the green, tee or fairway.

Case Study: Interseeding 007 Bentgrass into Penncross Greens.

A few years ago I visited Japan to conduct two seminars on bentgrass greens management to golf course superintendents.  The following information on interseeding bentgrass greens was presented by a Japanese superintendent who was a part of the same educational program where I was speaking.  I thought it was very good informaton to share with others, so, the following is a summary of what was offered.

Golf course superintendent Takaaki Nimori of the Kobe Golf Club in Kobe, Japan recently presented how he acheived good success with interseeding 007 creeping bentgrass into his established Penncross greens.  Over the three year period of interseeding 007 into Penncross greens the surface became denser while displaying a finer leaf texture. 

Below is the timeline for the 007 interseeding the process. 

Kobe Golf Club, Japan, interseeding time line:

2006　　September　 007 @ 10 Grams per square meter (2 pounds per 1,000 sq.ft)　

2007        March               007  @ 10 Grams per square meter

2007　　September　 007 @   8 Grams per square meter  (1.6 pounds per 1,000 sq. ft.)

2008　　March　　　   007  @  5 Grams per square meter (1 pound per 1,000 sq. ft.)

2008        June         　　007  @  5 Grams per square meter 

2008        September　  007  @  8 Grams per square meter

2009        April                  007   @  5 Grams per square meter   

2009        June                 007   @  8 Grams per square meter　　　　　

2009　　September      007   @  8 Grams per square meter

A total of nine solid tine - interseedings over a three year period.

Interseeding process conducted at the Kobe Golf Club, Japan:

 The first step in the process was to open the surface with a The holes made by a solid tine machine (above) should be close enough to provide as many openings as possible without damaging the surface.  The holes do not have to be more that 2.5 cm (one inch) deep.  

The objective is to have sufficient openings in the surface for the seed to fall into the holes so the seed comes in contact with the soil.  Seed simply deposited on the surface of the turf will not germinate.  For best results practicing interseeding multiple times a year in conjunction with use of solid tines, or spiking or hollow tine aerification is recommended.

Depost the seed using a drop spreader or look to purchase equipment that will spike and add seed and poke a hole and seed in one operation. 

After depositing the seed on the surface use a drag matt to move as much of the seed - that was deposited on the surface -into the holes.  　
　　

A light sand topdressing may be desireable if applied after the seed is droped and before the drag mat operation. 

Rolling the greens after use of the drag matt is the final operation in the process.

Interseeding following this plan is relatively non disruptive and is a proceedure that can be accomplished in one or two days (18 greens).

The photo to the right shows the surface of the green after punching the holes, applying seed, use of the drag matt and rolling the surface. 

The above described process will provide limited disrutpion to the green allowing golfers to play immediately after the green is rolled.

Close up of the green (below) in August 2009 after three years of interseeding with 007 creeping bentgrass.  Note the fine leaf texture and excellent plant density of the putting surface.

There is no question that interseeding into a Penncross green can improve the over all quality of the putting surface.  The key is to follow the interseeding guidelines and be patient as it may take two to three years to see a significant improvement.