Humboldt County’s Own Magnum is our high potency Magnesium/Sulfur boost with vitamin B1.
Magnesium is the essential element in chlorophyll which is what allows plants to uptake CO2 and use sunlight to make sugars, and B1 helps mitigate the stress of high performance bloom regimens.
Premature yellowing or fading of leaves indicates deficiency. The most common cause of Mag deficiency is the high Potassium levels of bloom boosters. Plants require a high PK boost for maximum yield so a Mag deficiency is always a potential threat. By the time yellowing is visible, bud development has already been affected and CO2consumption, which depends on chlorophyll, has slowed. That affects the whole plant.
If you are using Deep Breath to increase CO2 uptake, or you are using CO2enrichment, the accelerated growth rate you expect to see will not happen if you have a Magnesium deficiency. Plants grown under normal CO2 will be even more impaired.
WHY CAL-MAG IS NOT THE ANSWER
Excess Calcium can cause a Magnesium deficiency. Using a Cal-Mag to treat a Magnesium deficiency is like mixing poison with the cure because Calcium and Magnesium are transported through the plant by similar pathways, so excess Calcium can actually block Magnesium transport! The higher the ratio of calcium to magnesium the more magnesium transport is impaired. We’ve actually seen a Cal-Mag product worsen a Mag deficiency!
OTHER PROBLEMS WITH CAL-MAGS
A lot of Cal-mags are loaded with nitrogen (check the label) so you’re adding a “grow” nutrient at the very time when you should be cutting back. Some Cal-mags are fortified with Iron which is beneficial to plants because it helps to “green up” your plants. Unfortunately, if you are treating a Mag deficiency with a Cal-Mag product containing Iron, the plants will often temporarily green up and mask the Magnesium deficiency. You think you’ve cured the deficiency but it’s still there. Plants look better for awhile but the yield goes down.