Question From: Boston, Massachusetts, United States
Q: The potted geraniums on my terrace in Boston have new- growth leaves coming in light green with normal dark green edges. I checked the plants for aphids and whiteflies and find none.. Overall the plants still look healthy and robust and have some buds. They were teeming with flowers that when faded I actively deadheaded and then fertilized with miracle grow. Earlier in the season they showed some slight mildew so I have been spraying them every 10 days with Serenade Disease Control which I learned of last year when I saw mildew on that crop of geraniums. I have been growing geraniums on my terrace each summer for the last 6 years and have never seen the new growth light green. Yearly I pot in fresh soil that has some nutrient and over watering protection. I would appreciate any information on this condition. I have a small terrace and potted geraniums are my only crop. Thank you very much.
A: Two things come to mind. One is the soil is too wet. Wetting agents in potting soil pose a double edge sword. This year our weather has been cool and wet and the potting soil remains wet. Geraniums like to have their soil dry out a bit between watering. Second, Miracle Gro is high in salts and can cause burning when it builds up. I prefer to use a potting soil that is free of wetting agents and fertilizers. Sadly it is hard to find. Try a hydroponic store or a garden center that also grows plants. Too much fertilizer also can cause yellowing. I prefer using a fish and kelp fertilizer such as Neptune's Harvest. It too can be purchased at a hydro store or on Amazon. I do not change my potting soil out every year unless the plants have been diseased. I mix it with a good quality compost at a rate of 2 parts potting soil and one part compost. Hope this is helpful. Best Nancy
Q: Thank you for your prompt response; it was very helpful. I have cut back on watering and will eliminate any further fertilizing. My plants seem to still be thriving, but I wonder if I should cut off the discolored leaves to help speed the recovery.
A: You can remove leaves, but it won't speed the recovery. Best Nancy
