Help! My Pot Leaves Are Turning Brown

Photo by Canna Obscura
Dear Dan,
I’ve been growing medical marijuana for some time. I have three young plants from clones about 10-12 weeks old—outdoors in Southern California. They grow in pots in full sun. All three have begun to show the type of leaf seen here. There’s no sign of insects, but some of the middle leaves on all three plans are turning brown as shown in the photo. Two or three leaves at least on each plant exhibit this. Nice looking buds are forming but not ready for harvest yet. They have a strong MJ odor. Why the discoloration? I’ve grown before and have not seen this. — White11

Dear White,

It looks to me like you have a Phosphorous (P) or Potassium (K) deficiency. These types of deficiencies start in the older leaves and affect the margins between the veins of your leaves first. As it gets worse, brown rust spots appear and grow from the outside of the leaves inwards. Leaves and stems often turn red or purple and then progress to falling off the plants eventually. These types of deficiencies drastically slow down plant growth and can diminish harvests significantly.

There may be phosphorous and potassium in your soil but it’s unavailable to the plant roots due to salinity (too much fertilizer salts in your mix) or pH fluctuations. Before adding any fertilizer containing potassium, first flush your medium with plenty of plain pH balanced water. Then slowly introduce some mild NPK balanced fertilizer and be patient; new growth won’t show signs of healthy behavior for several days.

Total
7
Shares
Leave a Reply

Your email address will not be published. Required fields are marked *

Related Posts
cure
Read More

The Cold Cure

Freeze dryer technology is helping to speed up the drying and curing process.
Pink Boost
Read More

Following the Spirit

Cannabis breeder Katie Jeane finds harmony with Pink Boost Goddess.
breeding
Read More

Breeding for Dummies: How To Make Your Weed Plants Screw

Weed plants make sweet sticky love to each other just like your mammy and pappy did, albeit with a lot less grunting. Every time a weed plant gets laid, a new strain is born, kind of. But not every strain is destined for greatness. Read on to learn more about breeding.
Total
7
Share