How often should I test soil for prevention?
Written by
Benjamin Miller
Reviewed by
Prof. Martin Thorne, Ph.D.To prevent blossom end rot, you should test your garden soil every 3-4 weeks during the growing season. Frequent monitoring is crucial, as it enables you to detect pH shifts and nutrient deficiencies before they impact your developing tomatoes. I have dedicated a calendar to test soils every month from planting until frost.
Pre-Planting Preparation
- Test 4 weeks before transplanting to allow amendment adjustments
- Focus on pH calcium levels and organic matter content
- Correct imbalances with lime gypsum or compost as needed
Peak Fruiting Monitoring
- Test when first fruits reach marble size to ensure calcium availability
- Check magnesium and potassium levels competing with calcium uptake
- Perform quick pH tests using strips between lab analyses
Post-Harvest Analysis
- Test after final harvest to guide offseason soil improvement
- Evaluate nutrient depletion from the growing season
- Plan cover cropping or amendment strategies for next year
Use proper testing methods to determine the best results. Collecting samples from 6 to 8 locations at root depth is ideal. Allow samples to dry completely before mailing to labs. For rapid tests, mix soil and distilled water according to the kit instructions. I keep a specialized soil probe in my shed.
Adapt testing according to changing weather conditions. Test after a heavy rain, which leaches nutrients, or during drought conditions that cause salt buildup. Heat waves reduce nutrients and require more frequent checks. The rainiest season I experienced required biweekly testing to maintain calcium levels.
Results interpretation is done properly. I recommend the ideal pH for tomatoes pk is 6.5-7.0. Calcium concentrations should be above approximately 2000 ppm in sandy soils. Magnesium levels should be classified below Calcium levels to avoid competition. I check the chart from the extension service to compare my results.
Keep records for year comparisons. Enter the results and amendments applied for each test date. Keep track of plant responses in a garden journal. This history reveals patterns and helps you refine your prevention plan over seasons. My five-year records clearly show the optimal timing of amendments.
Read the full article: Tomato Blossom End Rot Explained Simply
