I think i have found the answer to my own question. I have read that this condition occurs when the soil is lacking iron, so i have started adding iron to the soil with the hope that it will help. Already i have seen some improvement and the new growth on the plants is looking much healthier. As an organic gardener, there is a consideration how to add iron to the soil. There is chelated iron that organic gardeners use but it contains EDTA to presumably help the plants absorb the iron. I am a little wary of this, so i have chosen unsulphured organic molasses to treat the plants with yellow leaves and the leaves that are turning white. I used a double dose (2oz/gal (4 liters) initially and will continue watering these plants weekly until the rains come with 1oz unsulphured organic molasses/gallon of water or compost tea. I believe the yellowing of leaves can be caused by watering too frequently so before starting the iron treatments, i made sure that over-watering was not the problem. Unsulphured molasses contains Potassium, Calcium, Iron, Vitamin B6, and Magnesium (no sodium) in the order of potency.
