Lucas Formula links
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Lucas Formula when growing in Coco Coir - Head's Formula
If you're growing in coco, you may need to adjust the Lucas formula slightly to compensate for a property of coco which may result in a calcium or magnesium deficiency. How? You may be able to get by simply by adding 1-2ml of calmag (or MagiCal+), or 1 gram of Epsom salt (any pharmacy carries this), per gallon of water, before feeding the plants.
There is a modified formula specifically for Coco that consists of using a different ratio: 6ml of Flora Micro, and 9ml of Flora Bloom, per gallon of water, along with 1 gram of Epsom salt per water.
Either works, but be sure to try Head's Formula if you're having deficiencies or other nute/pH problems.
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