Originally published on 10/16/14. Updated on 4/13/21

All wetting agents provide some hydration, but, relative to each other, some function primarily as “distributors,” and some as “retainers.” Which function they exhibit depends on how they are structured chemically. If the hydrophilic end of the EO-PO (ethylene oxide-propylene oxide) molecule is on the outside, as it is with Symphony®, the chemistry will create pools of water between the soil particles, resulting in retention. If the hydrophobic end (EO) is on the outside, as it is with Fleet®, water will be retained around the particle, but will move between the particles. This facilitates movement of excess water through the profile while still retaining water around the particle through absorption.

Which type of wetting agent you choose and how you use it, depends on a few factors. What you’re trying to accomplish, what the weather is, how efficient your irrigation system is, and how fast your soil profile drains.

Choosing your wetting agent

It’s important to keep in mind that wetting agents treat soil, not turf, so they only work where you put them. If you don’t water them in, all of the function remains near the top.  

If you have no tolerance for dry spots, you need to use a retainer, or use a distributor barely watered in.  If you would rather chase dry spots than disease, especially with low infiltration rates, you need to choose a distributor and water it in (within 18-24 hours) to the depth desired.

If you want water movement through the top 4”, you need to add enough water that night to move the chemistry through 4”. Unfortunately, it’s hard to say exactly how much that is. It depends on the efficiency of the irrigation system and how fast the soil profile drains.  Because Superintendents with push-up greens that don’t drain very well need the benefits of Fleet, they will typically use two cycles of irrigation to move the chemistry sufficiently, or they will apply Fleet in conjunction with a rain event.

Fleet was designed as insurance against too much rainfall. In a drought, if you used Fleet, you would need to be prepared to chase dry spots. Superintendents will often add an ounce or two of Symphony to their Fleet apps in very dry weather. 

The biggest variable, of course, is Mother Nature. Weather is not constant in the summer; you can easily move from hot and dry to cool and wet and back again. For that reason, a lot of Superintendents have decided to shorten the application interval to every 10-14 days. Since rate determines longevity, a shorter interval requires a lower rate. Typically, 5-6 oz is used for 30 days, and 2-3 is used for 10-14 day applications.

It’s fine to mix the wetting agent chemistries with other types (foliars, PGRs, fungicides) provided that you have enough free water in the tank for tank mix compatibility, and you water in the application that night. 

What makes the Harrell’s chemistries of Fleet^® and Symphony^® unique?

1. Branch structure: This gives you more activity sites around the soil particle, so you get more consistency over the application interval.
2. Stripper: Helps remove the hydrophobic coating around the sand particle. These hydrophobic coatings contribute to LDS.
3. Soil conditioner: This is a proprietary acid that helps break up bicarbonates and salts. Bicarbonates and salts lead to uneven flow and distribution of water, and that unevenness contributes to LDS.

Before choosing a wetting or distributing agent, talk to your Harrell’s rep about your water management goals, type of turf, soil structure, and efficiency of irrigation system. He or she will help you choose the best chemistry, rate, interval, and irrigation requirements.