compost in raised beds - Ask Extension
I filled my raised beds with compost from Green mountain compost. At gardener supply they told me that would be an awesome idea. My plants are stunt...
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compost in raised beds #874574
Asked June 25, 2024, 8:49 AM EDT
I filled my raised beds with compost from Green mountain compost. At gardener supply they told me that would be an awesome idea. My plants are stunted, yellow and generally unhappy. I am thinking there is a nutrient imbalance, perhaps I needed to mix something into the compost. Perhaps Green mountain compost didn't fully compost the material. I am unsure the reason or how to fix. Can you please help?
Chittenden County Vermont
Expert Response
Hello Aaron, and thank you for contacting the UVM Extension Master Gardener program with your question.
I am sorry to hear that your raised bed plants are not doing well this season. You are on the right track in thinking there is likely a nutrient imbalance, most likely too much of many good things! While compost is a valuable part of a garden bed, it is most effective as a soil amendment, not a replacement for soil when growing plants. And yes, sometimes compost is not fully ready for planting and can damage plants as they try to grow, though not common for product from commercial compost operations.
Proportions of compost to soil recommendations range from 25 - 50% compost. It will be important to do a soil test, to understand the levels of key nutrients and trace elements in your garden beds so that you can make appropriate adjustments to your bed mix for next year. Too much of certain nutrients can be harmful, and high soil pH levels can hinder plant uptake of nutrients, even when present in the bed.
Here are several articles that explain how best to utilize compost and establish healthy soil mixes for raised bed gardening:
https://extension.umn.edu/yard-and-garden-news/compost-and-soil-organic-matter-more-merrier
https://extension.umn.edu/nutrient-management-specialty-crops/correct-too-much-compost-and-manure
https://extension.umd.edu/resource/soil-fill-raised-beds/
https://extension.psu.edu/soil-health-in-raised-beds
The UVM Extension offers soil testing, and the details and submission form can be found through the links below. (No special test kit needed...just plastic bags to collect your samples.)
Instructions and fees:
https://www.uvm.edu/extension/agricultural-and-environmental-testing-lab
Submission form:
https://www.uvm.edu/sites/default/files/Department-of-Plant-and-Soil-Science/AGTesting/Garden_hort_questionnaire.pdf
Please let us know if you have additional questions. I wish you a better growing season to come.
- Michelle
I am sorry to hear that your raised bed plants are not doing well this season. You are on the right track in thinking there is likely a nutrient imbalance, most likely too much of many good things! While compost is a valuable part of a garden bed, it is most effective as a soil amendment, not a replacement for soil when growing plants. And yes, sometimes compost is not fully ready for planting and can damage plants as they try to grow, though not common for product from commercial compost operations.
Proportions of compost to soil recommendations range from 25 - 50% compost. It will be important to do a soil test, to understand the levels of key nutrients and trace elements in your garden beds so that you can make appropriate adjustments to your bed mix for next year. Too much of certain nutrients can be harmful, and high soil pH levels can hinder plant uptake of nutrients, even when present in the bed.
Here are several articles that explain how best to utilize compost and establish healthy soil mixes for raised bed gardening:
https://extension.umn.edu/yard-and-garden-news/compost-and-soil-organic-matter-more-merrier
https://extension.umn.edu/nutrient-management-specialty-crops/correct-too-much-compost-and-manure
https://extension.umd.edu/resource/soil-fill-raised-beds/
https://extension.psu.edu/soil-health-in-raised-beds
The UVM Extension offers soil testing, and the details and submission form can be found through the links below. (No special test kit needed...just plastic bags to collect your samples.)
Instructions and fees:
https://www.uvm.edu/extension/agricultural-and-environmental-testing-lab
Submission form:
https://www.uvm.edu/sites/default/files/Department-of-Plant-and-Soil-Science/AGTesting/Garden_hort_questionnaire.pdf
Please let us know if you have additional questions. I wish you a better growing season to come.
- Michelle
