11/19/2025
This penultimate* entry in our series on soil testing draws from the presentation delivered by Matt Williams, chief scientific officer at Predictive Nutrient Solutions, at this fall's WSU Master Gardener Advanced Education Conference. The Q + A details a few sample questions gardeners and farmers might have after viewing (and in some cases implementing) results from their soil test.
(*Because of a technical glitch, we ran the planned last entry in the series, a list of resources, on Monday, Nov. 17).
Q: I fertilized based on the results and my plants still look terrible, why?
A: Other causes of poor plant health
• Too much, too little water (Irrigation)
• Soil type? Rocky? Clay?
• Heat, cold
• Pollination problems
• Insect damage (above and below ground)
• Disease damage
• Shade, sun
• Allelopathy or competition
• Abiotic damage
• Fertilizer selection (when and how release nutrients)
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Q: What do I do if my soil has too much sodium?
A:
• Add gypsum
• Leach
• Must have good drainage
• Plant sodium tolerant plants
• Ex. Tall Fescue, Bougainvillea, Daylily, Mugo Pine, White Pine, alfalfa
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Q: Why should I consider adjusting my pH if it is out of the optimal range?
A:
• Nutrient availability
• Optimize plant growth and development (Think blueberries & alfalfa)
• Effect on soil microbes
• Avoid toxicity of certain elements, especially Aluminum in very acidic soils and sodium in highly basic soils
• What to use? Primarily Sulfur, Lime, Dolomitic Lime
• Irrigation water influence on soil pH
~~~
Q: I have high nutrients, what do I do now?
A:
• Don't apply fertilizers containing that nutrient
• Allow plants to uptake and remove that nutrient over time
– Macronutrients
– Micronutriente
– Leen More ©
• What about Nitrogen?
• Still fertilize?
~~~
Q: How can I use my recommendation to find products locally?
A:
• Look for products with similar ratios and containing the nutrients that are low
• This may be more than one product
• Calculate amount needed for your area to know amount to purchase and apply
• If uncomfortable doing the math to get new application rate, then follow the label directions
• 8-3-5
• 13-6-13