I have a small garden of eight indoor plants in a two by four growing area with a 1000-watt metal halide bulb. I am using a commercial soil and have adjusted the water to a pH of 7.0-7.5.
My babies are only two to three weeks old, but the earlier ones have turned pale yellow with no warning. The others are starting to yellow at the tips, so I used a 10-15-10 fertilizer with a cup of urine per gallon for the higher N. I also added some epsom salt in case they were missing some Mg.
It has now been three days of foliar feeding and using the mix for watering and they have not responded. How could this happen? I want to be a good father but might lose my little ones.
The primary problem your plants are experiencing is the unavailability of nutrients. This is being caused by too high a pH. As the pH edges up to neutral, nutrients become less soluble. Solubility decreases drastically in the alkaline range, which is over seven pH.
You have given the plants a heavy dose of fertilizer. It would be toxic if it became soluble. First flush the containers using water with a pH of 6.2-6.5. Test the ppm of the run-off water with a ppm meter. When the runoff measures below 1000 ppm, you can stop flushing. The nutrients will become soluble and the new growth will be normal. Don’t expect much recovery of old growth.
Start fertilizing again only when the plant starts to grow quickly. Use a complete fertilizer as recommended on the label. In the future keep the pH between 5.9-6.3
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