Advice on soil for outdoor window boxes and ceramic pots - Ask Extension
I have read various things and am very confused about whether I should replace some or all of the soil in my window box and outdoor pots every year, r...
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Advice on soil for outdoor window boxes and ceramic pots #827922
Asked May 01, 2023, 11:55 AM EDT
I have read various things and am very confused about whether I should replace some or all of the soil in my window box and outdoor pots every year, replace just the top 6 inches, sterilize it in black plastic bags in the sun, or what. It's expensive to keep replacing it, and on a small city lot I also don't have any place for the "used" soil. In most of these containers I am growing annuals, but in a few I am growing herbs, tomatoes and the like.
My other question is whether I should be using garden soil or potting soil or a mix of it in these large flower boxes and large containers.
I would really appreciate any advice you can offer.
Hennepin County Minnesota
Expert Response
Thank you for your patience with a response to your question. Container gardening requires potting soil rather than soil from the ground. Ground soil is heavier and does not allow for the roots of plants to expand in the small space. Potting soil is best for both flowers, herbs and vegetables. Replacement of potting soil is done each year to both replace nutrients and eliminate disease.
Tomatoes are require high amounts of nutrients and also easily pick up any disease from a previous year. I would recommend new soil for tomatoes. If your pot is much larger than your tomato plant you can use empty plastic bottles or other material to fill the bottom of the container so you do not need to fill it in entreaty with soil.
Flowers do not require as many nutrients as a tomato plant does. If you did not have any disease on your plants last year you can pull out 1/2 the soil and replace with new soil. With less new soil you may need to fertilize more readily throughout the season.
Enjoy the warmer weather and have fun planting!
Tomatoes are require high amounts of nutrients and also easily pick up any disease from a previous year. I would recommend new soil for tomatoes. If your pot is much larger than your tomato plant you can use empty plastic bottles or other material to fill the bottom of the container so you do not need to fill it in entreaty with soil.
Flowers do not require as many nutrients as a tomato plant does. If you did not have any disease on your plants last year you can pull out 1/2 the soil and replace with new soil. With less new soil you may need to fertilize more readily throughout the season.
Enjoy the warmer weather and have fun planting!
