Can Coffee Grinds Be Recycled?

Posted by Lynn Smythe Sep 3, 2008

It's that time of year. School started a few weeks ago so now everyone in our household is running around like a chicken with no head! My daughter did quite well on the FCAT's last year, she is above her age group for both math and language arts, so she was given all honors classes this year.

She is already stressing out about all the homework that is required for each class. Last night, she came to me at around 9 PM, to let me know she had to choose a topic for her science fair project. I asked when did she have to get the outline in, and she said TOMORROW - of course! Nothing like waiting until the last minute.

The science fair project will be the entire curriculum during the next three months of her honors science class. So we spent quite a bit of time trying to decide on a topic. I was hoping to get her dad involved, and was originally looking at electronic and aviation projects, but he seemed less than thrilled to help out.

So we started looking at all the projects that had anything to do with gardening or cooking, as these are two of my main interests. We found a page on recycling coffee grinds to see how they affected plant growth. I had an EUREKA moment - I have been using used coffee grinds in my organic garden for years, with fantastic results.

So here is the outline and initial plan for the science fair project:

Miss Heather’s Science Fair Project

Topic:

Recycling Coffee Grinds in Organic Gardens

Question:

Can coffee grinds be used to fertilize plants?

Method:

Use individual container gardens to test various soil to coffee grind ratios and the effects each mixture has on seed germination and plant growth.

Test Subjects:

1 container - filled with plain soil

1 container - filled with plain soil with coffee grinds added to top layer

1 container - filled with mixture of 75% soil mixed with 25% coffee grinds

1 container - filled with mixture of 50% soil mixed with 50% coffee grinds

1 container - filled with mixture of 25% soil mixed with 75% coffee grinds

1 container - filled with coffee grinds

Plant Choice:

Established tomato seedlings and tomato seeds.

Source For Coffee Grinds:

Starbucks

I never got to participate in a science fair project when I was a kid, so I am kind of looking forward to helping my daughter out with this project. We live in SE Florida, our main growing season is from the end of September to the beginning of May, so we will be able to setup our container gardens on our outdoor patio.

I'll post up more details of the project when they become available.

Take care,

Lynn Smythe

Herbs & Spices Feature Writer