Yellow marijuana leaves

A question from a fellow grower:

I’m growing a few plants outdoor in 5 gal containers - I have treated all plants the same - 3 are thriving - but the fastest growing ( now 4 ft hi) about 10 weeks old has yellowing leaves with brown spotting. This is a sativa dominant strain - grown in 420 potting soil. I first thought it was ph lockout the soils tested at a ph of 7 . I fed it molasses, then kelp - the following week - with no improvement - soil acidifier (sulfer) the following week I got some nitrogen - i also foliar fed it dr. earth nitrogen booster - the soil is now testing at 6.8 - I really dont know what to do - and help would be greatly appreciated - nothing has helped at all

Molasses? Why?

When you have a problem; You need to stop applying all these foliar applications and such.

I think; go back to basics, and get control of your plants. Spraying solutions on leaves can cause issues, unless you are diligent in your timing of the applications, and know what you are doing. Hope this helps

Blackstrap molasses is a good fertilizer boost and feeds the soil microorganisms

I only did one foliiar feed - just the nitrogen - cause I thought the roots had locked out nitrogen due to the PH - but I dont think thats the case now -

I think there is something about this particular sativa strain - I have 5 other plants all looking good

Nitrogen is not locked out until your ph goes below 5.4

Molasses draes pests. Spider mites, and white flies; Just to name 2. The usagrs do not break down correctly for the plant to uptake what you think you are providing. Maybe one good bath in early flower, might work, but constant application of Molasses is not necessarily in your best interest.

You should not continue to add products, minerals, kitchen ingredients to your 420soil. " Assuming you mean that this soil is a ready made formula for growing pot".

The biggest reason that cause growers to lose their plants: Impatience, and over nurturing. Let your plant grow and thrive before you spray all kinds of minerals and/or whatever on your plants.

trust me. Peace

I dont think you understand - I wasnt doing anything and my fan leaves started to yellow with brown spots - I lost a lot of leaves and thought maybe I should do something -

Like I said before - since all my other plants are thriving - I figure it has something to do with this very fast growing sativa strain -

anyway - thanks - I know you’re trying

A ph of 7 in a well balanced soil is not really that bad a place at all to be, in soil, and wouldn’t have likely been the cause of any problems. If you were not routinely adding balanced and appropriate NPK ratios to your watering regimen, you could very well be seeing nutrient deficiencies, and that makes even more sense with a very fast and aggressively growing plant.

I think you’re on to something - despite its problems it’s grown nearly a vertical foot since I posted this question - it might just be using all the nutes in the soil - thanks - i have a l0 - l0 - l0 and a 7-2-2 fertilizer - if u have a suggestion which to use - I’ll add it to my next watering

It depends what might be more readily available from the soil, but in general more nitrogen is needed in veg and more potassium and phosphorous in bloom/flower. So either would work if you are still in the veg season.

Thanks for all your help - It seems the plant was root bound - and therefore not able to absorb adequate nutes - I re potted into a 20 gal. container - and 2 weeks later - its fine - and now over 6 ft tall -

I have another question about the fan leaves turning pale green/yellowish with little brown dots on them. All the big fan leaves are being affected on my WW babies. I did some research and it seems like they needed some water and fertilizer. I used a 18-18-21 mixture today. The WW plants are starting to flower and the tops of the plants look great. I took the yellowish leaves with brown spots off the plant.

Is the 18-18-21 fertilizer okay to use in the flowering/bud stage? Or do I need to find a mixture with less nitrogen?

I’m worried the plants are going to all turn yellow with brown dots! Help!

Thanks so much,

They always need water and fertilizer, the question is are they getting the appropriate quantities of water or nutrients. Too much water can cause some nutrients to be locked out, calcium, magnesium and oxygen being the first to become unavailable to the roots. PH can be a huge factor, it can cause some nutrients to become too available, resulting in a toxicity, and others may become unavailable or locked out. See more in the answer on the other post.