Youtor
Run Off in Hydroponics Soilless Media Explained BETTER
>> YOUR LINK HERE: ___ http://youtube.com/watch?v=f7lRM2X-bkw
Today I'm testing the new OnePen™ by Bluelab—it measures pH, EC and temperature of nutrient solution simultaneously. Pretty cool! • https://resources.bluelab.com/bluelab... • I re-uploaded this video to fix the audio and some technical inaccuracies. Shout out to @brucetutton7897 for his gracious feedback! • Run-off is the excess nutrient solution that drains from your growing media after watering. In top-fed systems using coco coir or stone wool, aim for 25-30% of your daily nutrient solution to emerge as run-off. This practice prevents salt buildup in the root zone, maintaining nutrient balance and reducing plant stress. • Unlike soil-based gardening, soilless media require the grower to provide all nutrients through the feeding solution. The growing medium primarily offers physical support, water retention, and nutrient storage. This makes monitoring the nutrient environment crucial, which is where run-off testing comes in. • Neglecting to create run-off (under-watering) can lead to salt buildup and nutrient toxicity, resulting in burnt leaf tips, stunted growth, and reduced yields. This occurs due to selective absorption of certain nutrients while others accumulate, stressing plants and hindering nutrient uptake. • Environmental Factors Affecting Run-Off • High Air Temperatures: Accelerate plant metabolism and increase transpiration, leading to rapid salt accumulation and higher run-off EC. • Low Humidity: Creates high vapor pressure deficit, causing faster transpiration and higher nutrient concentrations in the root zone. • Intense LED Lighting: Increases demand for water and nutrients, potentially causing issues similar to high temperatures and low humidity. • Organic Additives and pH Stability • Organic additives like compost teas and hydroponic supplements can influence pH stability: • Compost Teas: Can lower pH and alter nutrient dynamics in the root zone. • Other Organic Additives: Products like humic and fulvic acids may affect pH stability and nutrient chelation. • Factors contributing to pH stability in nutrient solutions include buffering capacity, nutrient composition, and water quality. • Testing Run-Off • Measure two key factors: electrical conductivity (EC) or Total Dissolved Solids (TDS), and pH. • EC/TDS: Compare run-off to input nutrient solution. If run-off is 20-25% higher, it indicates salt buildup. Reduce nutrient solution strength gradually and consider more frequent irrigation. • pH: A rise in pH could indicate the release of basic cations, while a decrease might signal acidification from nitrate uptake or acidic residues. Adjust feed solution pH in the opposite direction of the observed shift. • When to Collect Run-Off • Immediate collection provides a snapshot of the root zone's condition. • Waiting for a minute gives a more comprehensive sample. • Collecting a composite sample over the entire irrigation cycle helps identify long-term trends. • Interpreting Run-Off Data • High EC in run-off suggests salt buildup from over-fertilizing or poor drainage. Low EC might indicate underfeeding or insufficient dry-back periods. • pH fluctuations can point to issues with water source, growing medium, or nutrient solution. Aim to keep root zone pH between 5.5 and 6.5 for most soilless systems. • Importance of Regular Testing • Regular run-off testing is crucial for mastering soilless growing. It provides valuable insights into root zone conditions and allows for necessary adjustments before issues become visible in plants. • Benefits of consistent testing include: • Preventing salt buildup • Maintaining nutrient balance • Avoiding pH fluctuations • Optimizing plant growth and yield • Make run-off testing a daily habit to keep your plants thriving. The more consistent you are with testing and adjustments, the healthier and more productive your plants will be. • Additional Considerations • Pathogens like Pythium or Phytophthora can damage roots, disrupting nutrient uptake and causing unexpected pH changes. • When mixing a remedial feed solution, aim for symmetry. If input EC is 2.0 mS and run-off is 2.5 mS, decrease feed strength incrementally to 1.5–1.9 mS until run-off returns to 2.0 mS. • Lower run-off EC than input (though less common) could indicate rapid nutrient uptake or nutrient retention by the medium. Consider reducing irrigation frequency or slightly increasing nutrient strength, but make changes gradually. • Always monitor plant health alongside run-off testing. Visual cues can provide additional insight into nutrient issues or root problems. • For consistent data, try collecting composite samples over entire irrigation cycles, but be aware this method can mask localized nutrient imbalances. • When adjusting nutrient solutions or irrigation practices based on run-off data, make changes incrementally and continue monitoring to avoid overcorrection.
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