So your 5 weeks from harvest and your leaves are beginning to turn purple. This is by and large brought on by a sudden phosphorus deficiency. On the off chance that the temperature dropped to 50 degrees (F.) your plant will increase the up take-up of phosphorus and that will make plants turn purple .Cannabis plants tend to love phosphorus in the blooming/growing stage in the event that you are utilizing legitimate growing supplements this shouldn't be an issue as most nutrient has more then enough phosphorous.
Phosphorus is utilized vigorously by cannabis plants in the blooming stage to create the buds, and is a urgent segment of photosynthesis (transforming light into vitality for the plant).
A few strains of cannabis utilize a great deal more phosphorus than others, or the reverse some can be more vulnerable to a phosphorus inadequacy, and you may have many plants in precisely the same with just a portion of the plants hinting at a phosphorus lack.
Why is this bad
At the point when your plants are lacking in phosphorus, this can general decrease the over all size of your plants. A lack of phosphorous causes moderate development and makes the plant end up plainly powerless, to little measure of Phosphorus causes moderate developments in leaves that might possibly drop off.
The edges all around the leaves or half of the leaves can be earthy and work its direction inwards causing the fan leaves to twist and become less effective in absorbing light.
How can this be reversed
Some inadequacy amid blooming is ordinary, yet an excess of shouldn’t go on without serious consequences. Any synthetic or natural composts that has Phosphorus in them will settle a Phosphorus deficiency. Affected leaves won’t demonstrate recuperation however new development will seem ordinary. It is best to completely flush the water if utilizing a nourishment supplement with no success.