Hi there, I’m a newcomer to gardening, and I have been given been seedlings to be grown in a container on my balcony. The plant receives 6-7 hours of sunlight and I have planted it in commercial miracle gro potting soil. While my other plants seem to be thriving and growing steadily, I’ve noticed that my fava bean plant has large white spots and holes in the leaves. I have been trying to diagnose the issue, and yet, I seem to find no exact match for nutrient deficiency or disease. The white spots seem to be prevelant on old leaves and may have spread to the new leaves as well.f Could you please tell me what is wrong with my plant, and if I should replace the soil and plant something else in the container?
Thank you for contacting the Toronto Master Gardeners
The photo you have submitted does not look like a fava bean or Vicia faba. It looks like a climbing bean plant. Please see photo and information on Fava Beans:
Broad bean or fava beans seedlings:
The information will be based on the bean plant or Phaseolus vulgaris. There are many pests that can affect the bean plant and leave holes, among them the Bean leaf beetle, or Flea beetle, aphids and mites. Check your plant for any pests and remove them by hand or with sticky tapes and spray with insecticidal soaps.
The white spots could be fungal spores: there are several types that can affect bean plants and are most likely caused due to our warm weather. Gray mold or white mold or mycelium fungus found in warm weather could be the cause. White mold will also result in water-soaked leaves and rot. Remove the affected leaves and keep good air circulation.
Leaves are light green and this could be a lack of Nitrogen or Phosphorous as Nitrogen is a key element in bean’s photosynthesis and leaf growth. A deficiency causes yellowing leaves and a general paleness. However, like all legumes, beans have the ability to manufacture their own Nitrogen. Therefore lack of phosphorous for reproduction, cell growth and fruit production may be lacking. Adding 2 to 3 inches of compost should improve your soil to retain moisture, improve drainage and add beneficial microorganisms. Additionally, compost suppresses diseases and pests while promoting healthier plants. You can also fertilize with a 5-10-5 which is high in phosphorous.
If you do not find any pests or can rule out fungus and have tried a high phosphorous fertilizer without results, it would be best to start over. Get rid of the existing soil, sterilize the pot and start with new seeds and sterilized potting soil, adding compost.
Enjoy the summer bounty
June 9, 2021