Can We Use Potting Soil From Last Year Or Do We Need New Potting Soil Every Year?

Question

I typically grow tomatoes in a large pot and want to know if I can use the same soil I used last year to grow tomatoes this year. Can you recommend amendments to the soil that would make this possible? Also I typically grow petunias, geraniums, and veronica in large pots. Do these pots also need fresh potting soil every year, or can I just add 4″ to the top layer of soil?

Answer 1

Instead of adding soils, I would add compost or liquid fertilizers. I would, first, test the soils. Here are some articles to help:

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/testing-soil.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/soil-ph-plants.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/fertilizer-rates-and-applications.htm

https://www.gardeningknowhow.com/composting/manures/steer-manure.htm

https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/compost-as-soil-amendment.htm