Everything You Need to Know About Buffering and Conditioning Adjuvants
Dr. Christophe Duplais, Cornell Agritech
There are many adjuvants available that are suggested to be combined with pesticides, but not enough information about their role and efficacy. This article focuses on adjuvants that control water pH and water hardness to make sure pesticides perform at their best. The bottom line is the quality of the spray water is just as important as the pesticide itself.
Spray water quality is very important in pesticide applications. Remember that spray water quality concerns pH, hardness, and alkalinity, and is different from the microbial concerns we test for in water quality for food safety. This article deals with water quality only in terms of its impact on pesticide efficacy.
General information of water pH and hardness
- pH measures the acidity of water, from acidic to alkaline
| 0 < pH < 6 | pH = 7 | 7 < pH < 14 |
| Acid | Neutral | Alkaline |
- Hardness measures the concentration of dissolved minerals (calcium and magnesium) in water in grains per gallon (gpg) or in part per million (ppm), equivalent to mg/L. These minerals come from calcium carbonate and magnesium carbonate.
| 0-3 gpg | 3.5-7 gpg | 7-25 gpg |
| 0-60 ppm | 60-120 ppm | 120-425 ppm |
| Soft to slightly hard | Moderately
hard |
Hard to very hard |
- The alkalinity test measures the carbonate part in calcium carbonate and magnesium carbonate, while the hardness test measures the mineral part (calcium and magnesium).
- Measuring water pH and hardness is more informative than alkalinity alone
- Water pH and hardness vary depending on the time of year and location in NY state.
- Hard water neutralizes acids, preventing pH from dropping (becoming acidic).
Water pH and hardness impact pesticide efficacy
- Water pH affects the stability of most pesticides.
- Pesticides work best within a specific pH range between 4 (acid) and 7 (neutral).
- When water is alkaline (pH > 8), pesticide active ingredients are less stable and may degrade.
- Dissolved minerals (calcium, magnesium) can bind to active ingredients, reducing their efficacy and causing precipitation (clogging spray nozzles).
How buffering and conditioning adjuvants work?
Buffering adjuvants are used to adjust and stabilize the pH of the spray solution to the optimal pH range of 4 to 7 (see below for examples).
Water softening with conditioning agents removes calcium and magnesium by binding strongly to the minerals, preventing them from binding to the active ingredients (see below for examples).
Best practices for using buffering and conditioning adjuvants
(1) Test your water regularly
This should be carried out regularly, at least every month during the growing season, or before every spray if possible.
- pH Testing:
- Use test strips to measure the pH of spray water. pH strips with a multiple color indicator and a different pH range, or pH paper rolls, which are available online (Amazon) (see photo). In general, pH strips are more accurate than paper rolls.
- If you are in doubt about the results because the reading is between 7 and 8, add a buffering adjuvant to ensure that your pH is below 7.
- Hardness Testing:
- Test strips for water hardness are also widely available and easy to use. If your water is > 7.5 gpg or 120 ppm, the water tank should be treated with a water softener.
(2) Choose the right buffering and conditioning adjuvants
- Carefully read and follow the instructions on the adjuvant labels. It is essential to use the right quantity to obtain the desired adjustments.
(3) Order of Mixing:
- Always add the buffering and conditioning adjuvants to your tank water first, before adding the pesticides. This ensures that the water is buffered and conditioned before the active ingredients are added to the tank.
Examples of buffering adjuvants.
There are many products available for only buffering the pH of water, or with multiple functions. Products for pH buffering only:
- Buffer P.S. (Helena)
- Buffer Xtra Strength (Helena)
Buffering adjuvants with multiple functions:
- Li 700 (Loveland Products) is a pH buffering and a spreader/penetrant and drift control agent.
- Indicate 5® (Brandt) contains a pH indicator, turning the spray tank water pink when pH value of 4.5-5.5 is reached. It is also a spreader/penetrant.
Examples of conditioning adjuvants
There are very few conditioning adjuvants available. It is best to choose a product containing citric acid (acid in lemon juice), a good mineral binder whose acidity also lowers the pH. EDTA is an excellent water softener, but it is a persistent substance in the environment that reduces the bioavaibility of metals (iron, copper, etc.) essential to soil health and its use should be limited.
Products for buffering and conditioning:
- pH Adjust (Brandt)
- Crimson® NG (Winfield United)
Products with multiple functions:
- Weather Gard™ Complete (Loveland Products) is a deposition aid, drift control agent, penetrant (spreader), antifoam, and water buffering and conditioning agents
- FS AMS MAX DR TM (Insight FS) is water conditioner/AMS, drift reduction, surfactant.
Note: Ammonium sulfate (AMS) is a common fertilizer. It is a mineral acid that lowers the pH of spray water. It also dissolves calcium carbonate. Ammonium sulfate can be considered as a buffering and conditioning agent.
Examples of OMRI listed adjuvants for both buffering and conditioning
- pH Down (SafeGro Laboratories)
- MixWell Acidifier (JH Biotech)
- CitriSan (Organisan Products)
- Constant BUpHER Acidifier (Brandt)
Christophe Duplais
Cornell AgriTech
c.duplais@cornell.edu
Photo 1. Examples of different pH strips and hardness strips. pH ranges from 0-14 and 4.5-10, hardness range 0-425 ppm. Price is about $10 for 100-150 strips.
Photo 2. Easy, inexpensive testing of water pH and hardness using strips. Example of readings from sink water at Cornell AgriTech’s. The pH is between 7 and 7.5 with multicolor strips and between 6 and 7 with paper roll. Multicolored pH strips are more accurate than pH rolls. Water hardness is 7 gpg (120 ppm). Conclusion: this water needs to be treated by buffering and conditioning adjuvants.
