High phosphorous in garden plot - Ask Extension
On a recent soil test done by the U of MN, we found that our community garden plot has a high phosphorous levels. I have done some reading on what th...
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High phosphorous in garden plot #868965
Asked May 17, 2024, 9:05 PM EDT
On a recent soil test done by the U of MN, we found that our community garden plot has a high phosphorous levels. I have done some reading on what they sent along with the report as well as my own online searching. It seems like the best plan is to grow a cover crop of a cereal (wheat, or rye, etc.) but I don't want to do that now when I am doing my major spring into summer planting. Is there a crop that will do the anti-phosphorous job that we can plant mid-summer? A faster growing on? What would you recommend? I do understand that pulling up the plant after it grows is a key step. Thoughts? Thanks.
Hennepin County Minnesota
Expert Response
I would not bother with a cover crop to remove the excess P. The excess P doesn't typically harm plants. Why waste a growing season to solve a problem you may not have?
Most of the sites that I've seen suggesting that excess P is harmful to plants are in southern states which have quite different soils and growing conditions. The University of Minnesota does mention cover crops to trap P, but I wouldn't do this unless my plants are showing stress. Excess P can cause other nutrients (zinc and iron, specifically) to be less available. Read here:
https://extension.umn.edu/yard-and-garden-news/you-might-be-over-fertilizing-your-garden
The primary, and significant, hazard of excess P in our region is in runoff and how phosphorus contributes to algal bloom in our lakes and streams. So be aware of where your plant debris and soil goes. Keep it all on site. Do not let plant debris or soil run off during a rain event.
Most of the sites that I've seen suggesting that excess P is harmful to plants are in southern states which have quite different soils and growing conditions. The University of Minnesota does mention cover crops to trap P, but I wouldn't do this unless my plants are showing stress. Excess P can cause other nutrients (zinc and iron, specifically) to be less available. Read here:
https://extension.umn.edu/yard-and-garden-news/you-might-be-over-fertilizing-your-garden
The primary, and significant, hazard of excess P in our region is in runoff and how phosphorus contributes to algal bloom in our lakes and streams. So be aware of where your plant debris and soil goes. Keep it all on site. Do not let plant debris or soil run off during a rain event.
Thanks, Dennis. Very helpful & I appreciate the time and advice. Kari
On May 18, 2024, at 3:37 PM, Ask Extension <<personal data hidden>> wrote:
