Pining in the Poles: My Pole Beans Are Not Producing


“I bought Bountiful Stringless Bush Beans and Blue Lake Pole Beans in Feb2010 and planted them side by side.The bush beans did fine but the pole beans grew 7 feet up the trellis with not one green bean. I had 35 feet of healthy vine but wondered why no fruit when the bush beans were productive. I live in PA. Any suggestions are welcome. ~G.”

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Thank you for your email regarding your Blue Lake Pole Beans.  How disappointing!

There are several reasons why your beans may not have produced:

1)      Beans are even more intolerant of excess nitrogen – one of the most common causes of blossom drop – than those other plants are. Pole beans are even more sensitive to this than bush beans because they have more biomass.  Excess nitrogen results in huge lovely plants but no beans.  Beans can make their own fertilizer by nitrogen fixation.  This occurs by a process called symbiosis, in which a bacteria is embedded in the root tissues of the plant.  The areas with bacteria swell into structures called nodules.  The bacteria convert nitrogen (from the air in the soil) into a solid form that can be used by the plant.

2)      Beans prefer temperatures between 70-80.  If the maximum temperature is consistently over 85, the flowers will drop off without setting pods.  Heat can also cause the blossoms to deteriorate on the plant without actually dropping off.  Hot dry winds also aggravate this situation.   If the maximum temperature is consistently under 70, the plant will not initiate flowering.  Bush beans are more tolerant of temperature than pole beans are.

The Pennsylvania area did experience a very warm summer, so it is likely that could have greatly contributed to the poor blossom set.

Based on the information from your email, I am guessing that one of the above is the source of your problem.  Other reasons include:

3)      Extremes in soil moisture.  Plants growing in soil that is too wet or too dry are stressed by a lack of oxygen and water.  Stress makes blooms drop.

4)      Again, probably not the case based on your description, but weakened plants produce few pods.  If your plants had any type of disease, this would have made it more difficult for the plant to set pods.

5)      It is not uncommon for a person to have an initial lag with pole beans when compared to bush beans.  Bountiful is a 47 day variety whereas the Stringless Blue Lake S-7 is a 60 day variety.  The tradeoff is that bush beans do not produce as much but give you a crop sooner whereas the pole beans take longer but produce more.

6)      If your beans are planted too close together, the production goes way down.

7)      If you let your beans mature the plant will stop making more beans. This is probably not the case because you didn’t have any to begin with, but thought I’d say so because it is the problem experience by most of our customers that ask the same question as you have.

If you have not had your soil tested, I would recommend doing so.  This will allow you to know what your starting point in the spring is in terms of how much nitrogen to apply for your beans.  Also, it is good to know what type of soil you have.  If your soil is heavier (as opposed to being sandy), then your nitrogen requirements are going to be even lower because it is held in the soil rather than washing out.  Sandier soils tend to have the nitrogen leach throw the porous texture and be washed out.

As for doing something to aid with the temperature, there is not much we can do with that other than pray.  =)

 

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© Mertie Mae Botanics LLC and Horticulture Talk!, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Mertie Mae Botanics LLC and Horticulture Talk! with appropriate and specific direction to the original content.

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5 thoughts on “Pining in the Poles: My Pole Beans Are Not Producing

  1. I need to get clarification. I have tons of blooms as well as healthy vine. If you have blossoms with no beans, that can be do to excess nitrogen?

    • No, if you have the blossoms, then you do not have a problem with nitrogen. Having blossoms but not beans is a temperature problem.

  2. We’re very happy with your expertise on this problem. I had been ready to till mine under, but thanks to your article, I waited it out and now have a wonderful crop. Thanks!

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