Everyone who grows has had a plant or two mysteriously die on them. Symptoms may have varied widely, and maybe some plants were stunted runts that managed not to die. These mysterious deaths and delayed growth may just be a case of missing trace elements.
The seed of the cannabis plant contains all of the trace elements the plant will need for the first 2 to 3 weeks of growth. After that, though, your plants need to have trace elements given once a week. Any less than that and the plants will still have a nutrient problem. Any more and the nutrient will be given the free molecules required to bond the essential nutrients covalently, making them unavailable to the plant.
Common trace elements are iron, Silicon, Molybdenum, Cobalt, Copper and yes, even Chlorine. Find yourself a trace element brand that has at least the elements given in this document. It’ll most likely be a dark liquid in a dark bottle with an eye dropper for dispensing metered amounts. I recommend a liquid with the trace elements in suspension rather than a dry mixture. There’s less to do and it will dissolve into your nutrient solution immediately. A dry additive will no doubt require you to agitate your nutrient. Most dry additives I’ve experimented with required a scale that can measure in milligrams to dispense the proper amount of nutrient as well.
Know a trace element deficiency first by a peculiar rotting of the center veins of each leaf, usually on the bottom-most fronds first. The plant will fall behind in growth as compared to the other plants it’s growing with and the root ball will begin to die and rot in extreme cases. Trace element deficiencies are often misdiagnosed as a case of slime mold because the root system has begun to die off and the root ball will smell rotten.
Those of you who are running into a trace element deficiency only have the option of cutting off the leaves and fronds that are affected. If you were to leave the rotten fronds on the plant it will slow in growth because it’s spending all of its resources trying to repair a damaged leaf that is beyond repair. Cut the fronds off with about a centimeter of stalk left. The plant will seal off that frond with a brown callous and will continue to grow normally.