Rural Heritage October/November 2025

Understanding Soil Tests HPD 2025 Seminar

Tomatoes come from the Peruvian mountains. They’re sensitive to ammonia. If your leaves look like bubble wrap, that means you have abnormal growth and a problem. As a rule of thumb, two-thirds of your nitrates should come from nitrogen fertilizer. Keep track of nitrogen in tissue samples. The plant pulls up nitrogen like a pump. Some 80% of blossom end rot is caused by moisture management. Inside the greenhouse, you need effective fertilizer and shade. Keep your fruit under the leaves. Outside the greenhouse, you need enough water. You need two pieces of drip tape per plant. The more evenly you water, the more even your fruit development. Red Deuce tomatoes send out suckers that you need to prune. Challenge environmental stresses before they become plant problems. Most of all, Pat said to look for trend lines.

by Mary Ann Sherman P at Owens said that you should take a soil test every year. You need multiple years of testing to determine trends. When you take a soil test, kick off the top layer of the soil with your heel. This layer has higher organic matter than the rest of the soil that you are testing. Soil testing is more of an art than a science, but it’s still a science. The pH inside the high tunnel greenhouse was 7.2. When potassium is two times greater than the magnesium, you likely have a magnesium deficiency, especially for Red Deuce tomatoes. If potassium is less than 2%, you need to add potassium. Use dolomitic lime, which contains both calcium carbonate and magnesium carbonate. There used to be a great concern about acid rain, but not so much anymore. The sulfur in acid rain is important for flavor and color. Don’t go crazy with micronutrients. Don’t apply them in large amounts. You want to spoon feed micronutrients. Look for trend lines. You want to take a water sample at least once a year. If your aquifer gets low, the minerals in your water will become more concentrated and test higher. Test your pH without fertilizer and then again with fertilizer. Try to be consistent. If you test on a Monday, the next time you test should also be a Monday. If it’s 65 degrees today and 90 degrees the next time you want to test, be aware that the results may vary a lot. Perhaps wait until the next Monday when the temperature is closer to 65 degrees. If something tests very high or very low, don’t freak out. Make small incremental changes. Soil and water testing facilities hold their results for a time. If your soil or water test comes back really out of range, it may pay to submit another soil or water test to see if you get the same outlandish results. The darkest green is at the end of tomato leaves. It’s a bad sign if your dark green leaf matches the stem.

October/November 2025

11