Yellowing Green Bean Posd

(Question)

Hi, I am growing Black Valentine bush beans in a container and in the last two weeks have notice that new fruit is yellowing and stunted, and perhaps not developing further. Already developed fruit have kept growing and I have had a consistent harvest every 3 days for a few weeks as well. The plants also have new flowers. They were planted at the beginning of July.

I can’t find much info on these symptoms online. Is it a disease? Too much/little fertilizing? The leaves seem healthy though some lower ones are yellowing, which I remove. They are planted in a grow bag filled with Pro-Mix Vegetable and Herb (mostly peat + perlite). Fertilized weekly or biweekly with Neptune’s Harvest Fish + Seaweed Emulsion (2-3-1) and Dynagro Foliage Pro (3-1-2) at half strength to avoid salt buildup as they are subirrigated by sitting in a kiddie pool with 1-2″ water and wicking it up. So watering is consistent. I don’t believe they are overwatered as the bags are quite aerating and there has been no change from before with the watering regime? But I am no expert.

Photo attached, thanks for any advice you can offer.

(Answer)

Beans are one of the most popular home grown vegetables and have some specific requirements for a successful crop yield.  You have certainly done your research and are treating your bean plants well, perhaps too well.

The stunted growth may be the the result of two factors, one within your control, the other not.  Beans grow best in temperatures between 18 and 30 degrees.  Nature has not been too cooperative with night time temperatures falling to 12 and 14 degrees.

After an application of a complete fertilizer and 2-3 inches of organic matter worked into a soil depth of 6 inches at planting, beans do not need additional fertilizer.  Beans fix their nitrogen from the air through soil bacteria via the plant’s root system.  Too much nitrogen stimulates foliage growth and the beans will not grow to their full potential.

Hold off on the fertilizer and hopefully the weather will stay warm.  Good luck and happy harvesting.

You might find this web site helpful: https://extension.uga.edu/publications/detail.cfm?number=C1006