Verti-Drain machine. This process involved about 170 hours of labor, 42 tons of sand, 900 pounds of a soil amendment product, and approximately 1.6 million 1/2" solid tine holes put in our greens, collars and cool season approaches at an average depth of 7.5 to 8.0".
Our process included the following:
- Mow the greens
- Placed a layer of sand ahead of the aeration
- Aerated the greens
- Applied a 50# bag of the soil amendment material to each green.
- Blew, brushed and pushed the sand into the holes and did a final smoothing of the sandy surface with a drag brush.
- Rolled the green surfaces to smooth the surfaces
- Changed the holes
- Mowed green surfaces with an old set of reels to cut off the tufts of bent grass or longer leaves of plants that were lifted up during the process.
- Watered greens a couple of minutes
Aeration of our greens are one of the most important cultural practices that take place on our golf course for the year. We complete this process for a number of reasons:
- Improves drainage through our green profiles and assists in drying out wetter sections of greens.
- Exchanges good gas(oxygen) with an overabundance of bad gas(carbon dioxide).
- Improves drainage and oxygen which is great for developing new roots and improving existing root systems.
- Additional sand on the surfaces assists in smoothing the surface after the holes close back together and protects the crowns of the plant which is where roots and leaves start their lives.
- It also helps to dilute thatch or improve the mat layer which reduces the effects of ball marks and speeds up the process of healing as long as the mark is repaired by the golfer.
Topdressing machine puts a layer of sand on the greens at about a depth of 1/4" more or less. This is the same machine that we place a very light topdressing layer on our greens during the season. Approximately 3 hoppers of sand for the total golf course. It takes almost 2 loads of sand per the average sized green during aeration. A green such as 1 green we go across it 3 times for very light topdressing. During aeration, its about 10 passes which could increase tire tracking on the greens which we attempt to prevent.
The sand is kiln dried and reaches a temperature of well over 1000 degrees which dries it and kills the weeds and the bad actors in the sand. We brought our 45 tons of sand in on Thursday before the Monday activity so it would have a chance to begin to cool before placing it on the greens. Sand too hot being put on at the heavier rate could literally cook the bent grass.
We started the process before first light on Monday morning.
A daylight view of the aeration. As you can see, 4 tines per holder with 6 arms placing 24 holes in our greens every 3" at a depth on average of nearly 8".
|Tom spreading soil amendment product which includes: Dry kelp meal, greensand, compost, rock phosphate, sulfate of potash magnesia, calcium carbonate, humic acid, zeolite, and compost.|
|Pull behind blower and staff using back packs during sand into the hole.|
|Dark thirty the 2nd day.|
|Hole filled vs no fill.|
|Completed, holes to the top!!|
1. Below are pics of the end results.You can see the channels down into this 7" section of the practice green. The topdressing/sand layer has been applied to the greens for the last 30 to 40 years. At the last 2 inches is the soil layer which is being incorporated with aerating/topdressing sand over the years to allow moisture to drain out of the system.
2. Our overall roots grow in the top 3-4" of our profile but we have longer roots growing through aeration holes deeper in the profile up to 7" or more as you can see below.
3. A large aeration hole from our Dry-Ject process that takes place each late winter/early spring up to 4" to 5" deep.
4. After the rains overnight and into this morning, water at the bottom of the 7" deep hole where I pulled a hole. This moisture works through the 5-6" deep sand layer of the green and then enters through the 2" soil layer more quickly because of the deep-tine aeration holes. It will move directly through the soil and a much slower pace because of the tight soil particles.
5. Below is a standard drainage system in most modern greens. We have one green that has drainage set up this way, green 9 renovated in the late 80's. This system is designed so water will drain through the 12" sand layer represented by the dark section on top. The water will slowly build up in the bottom 3rd but will slow at the next layer which is gravel which creates a perched water table. The construction of this type of system in golf greens is to allow roots the opportunity to take up moisture into the bent grass plant as the water passes through the sand. Once the water pressure increases enough at the bottom of the interface between the sand layer and gravel, it then releases into the gravel layer. Too much moisture for too long of a period of time in the root zone will deprive the plant of oxygen which is needed for the plant to survive.
This is once of the issues we have with our greens at Glen Echo which do not have standard drainage systems. A higher than normal period of moisture can lead to negative results both on the putting surface and below surface in our root systems.
Once the water begins to drain through the gravel system it will then enter the small holes in the drain pipe and will exit from the green area.