TDR300 4.8" or 1.5" probes? Cancel The title field is required!

1. Jonathan Wyrick

   

   0 posts
   
   6/28/2012 9:06 PM

   I'm in the Carolina's on usga LS-44 bentgrass greens. I recently purchased a TDR300. It came with a set of 4.8" probes. Its my first time using this meter. Still looking for my baseline. I think some where around 13-15% for now with this size probes. A super at another course in town uses the 1.5" probes for their measurements.
   Question: What length probes are people using on bent greens?
   I would think the measurements should be taken down in the root zone with the 4.8" instead of in the thatch layer in the top 1.5".
   Question: If you are using the 1.5" are you still doing deep infrequent watering and touching up with hand-watering?
   With the 4.8" I feel I should be more accurate in keeping moisture levels consistent in the root zone. This requires me to water more often with less water than I every have in the past.
   Question: Does this logic make sense or am I way off base?

   
   
   
   
2. Patrick Reinhardt

   

   0 posts
   
   6/29/2012 7:06 AM

   If your roots are shrunk up in the summer, then it won't matter what the moisture reading is at 4.5". Heat of the summer, I worry about the top 1" where most of the roots are.

   
   
   
   
3. Sam Welch

   

   0 posts
   
   6/29/2012 11:06 AM

   I have the 1.5, 3, and 4.8 inch probes but have only used the 3s. Now that we've established our numbers with the 3s I'll probably stick with them the whole summer, you get different readings with different length probes.
   
   Whichever ones you chose, just find YOUR number(s), where your greens are wet, at what point they wilt, and where your happy medium is. Such a great tool.
   
   Didn't read your post well enough...I definitely think the meters lead you to more light and infrequent watering trying to maintain that level instead of going through peaks and valleys. I've had that discussion with my assistants and other supers, it kind of goes against what you're "supposed" to do but it's working for me so far.

   
   
   
   
4. Patrick Reinhardt

   

   0 posts
   
   6/29/2012 12:06 PM

   Sam,
   Michigan State teaches light and frequent. It's always been my preference, and worked for me. In the words of Joe Vargas, "The roots don't know where the damn water is. They just grow!"

   
   
   
   
5. Kenneth Ingram

   

   18 posts
   
   6/29/2012 2:06 PM

   Those 4" probes will start to bend outward on you pretty soon and as you know they are not inexpensive. Use the shorter ones. Kenneth Ingram, UMD

   
   
   
   
6. Kristofer Davis

   

   0 posts
   
   6/30/2012 11:06 AM

   We use the longer, 4.8", probes here in Tulsa all year long. We water anything below a 10 right now and typically make it 4 plus days without needing the heads in 100+ degree heat. We adjust slightly the percentage we water according to season, but that has kept our roots deeper and greens fairly firm considering the season. There are people in the area that water every night with success, just not how I was brought up I guess. I always felt if you water every night, your roots have no need to grow deeper.
   
   From experience, I would suggest picking one length and sticking to it all year long. That way you can benchmark your moisture and water needs with consistent feedback your meter is giving you.

   
   
   
   
7. Daniel Mausolf

   

   0 posts
   
   7/1/2012 4:07 AM

   We use the 3" all season long on bent greens here in Michigan

   
   
   
   
8. Joey Brown

   

   0 posts
   
   7/11/2012 6:07 PM

   I'm with Sam and Patrick on this. I have 2 meters and my asst and I switch back and forth between 3" and 1.5" on the greens as I am getting my morning readings. Then throughout the day, I prefer the 1.5" probes. I have also gone more toward light and frequent and so far this year have had better results. It is a valuable tool, but you HAVE to find YOUR numbers. And those numbers change throughout the year. In a month when my roots are shrunk, I will not use anything but my 1.5" probes, because I won't have roots at 3" to utilize any water there.
   
   Joey Brown
   Canongate at Georgia National

   
   
   
   
9. Melvin Waldron

   

   43 posts
   
   7/12/2012 8:07 AM

   I have a question, when choosing between the 300 and the 100, are any of you using the data loggers? Any of the other benefits of the 300 has the the 100 doesn't? Spending that kind of money around here I need a good reason for it. Anyone else think there are other meters that work as well or good?
   
   Thanks! Mel

   
   Melvin H. Waldron III, CGCS, Horton Smith Golf Course, City of Springfield/Greene County MO
   
   
10. Robert Wright

    

    0 posts
    
    7/14/2012 4:07 PM

    I use the 3" because it gives me the center of the root zone mass. We will take the greens down to around 12% then water deep, bringing them back to 25%. What the tool helps is to keep the green consistent, if its measuring 19 all over, but a couple spots are at 13, we will bring those spots back to 19. Has helped identify the hot spots, and to keep consistency from irrigator to irrigator to assistant to me.

    
    
    
    
11. Larry Stowell

    

    0 posts
    
    7/15/2012 9:07 PM

    The video posted below illustrates the results form the 3, 4.8 and 8 inch probes and compares the TDR300 to TurfGuard sensors.
    
    I have used all probe lengths and have worked with superintendents who have various preferences for probe lengths. I tend to prefer the 4.8 inch probe because it averages over a deeper profile - calms down the variability in readings. The longer probes also tend to report slightly lower soil moisture and that, I believe, provides a more conservative look at soil moisture - it prevents you from running too dry.
    
    I just had a set of poa greens samples arrive at the lab that had some drought stress and the superintendent recently switched from the 4.8 to 3 inch probes. I suspect that the higher readings when he switched to the 3 inch probes helped lead to the drought damage. I am not a strong proponent of running greens at the minimum moisture level - it is too easy for a little extra wind to dry things out. As long as you use the meter regularly and keep track of greens performance and volumetric water content, you will gain confidence regardless of the probe length you use.
    
    http://www.youtube.com/watch?v=B9pgf6ClapQ
    
    Larry