Question
I have a plant under grow lights in my basement for the winter and it has done very well outside during the summer season.  Yet the past couple of months the leaves have gotten increasingly chlorotic.  I use a mild houseplant fertilizer in the water I use for all my houseplants.  It is in about 60-65 degrees and not near any heat register.  I water it usually once a week.  Can you let me know what might be the problem?  Thanks.

Answer
Hi Nancy,

Chlorosis is a lack of chlorophyll production usually due to nutrient deficiency. The most common cause of nutrient deficiency is not lack of fertilizer, but improper soil pH. Soil pH is the degree of acidity and if it is outside the proper range, mineral nutrients become insoluble and are rendered unavailable for the plant to absorb. So there can be an abundance of nutrients in the soil, but if the soil pH is out of range, then the plant will suffer from lack of nutrients.

Jasmine soil pH should be in the slight acidic or 6.0-6.8 range. If your local tap water is on the hard side, then there is a good chance that the soil pH has increased to a level outside that range. You can remedy this by applying Mir-Acid fertilizer once or twice after flushing lots of distilled or filtered water through the soil of your Jasmine. After one or two applications of the Mir-Acid over the course of two months, resume using regular fertilizer. Continued use of Mir-Acid will cause the soil pH to drop too low. Do continue to use filtered or distilled water.

Although already yellowed leaves may not green-up, new growth should be a healthy green color after correcting the soil pH.

You used the term "chlorotic," so I assume you understand its meaning. However, Jasmine are highly susceptible to spider mites that can cause the leaves to have a pale, mottled appearance. This is not chlorosis, but it is possible you are confusing the two. If so, let me know and I will send you information of spider mite treatment.

I have written an article on Jasmine care and soil nutrients that I will email for free to you (or anyone else) who sends a request to me at [email protected].

Please let me know if any of this is unclear or if you have any additional questions.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

Visit my website at: A link to PlantCareExperts.com