Homemade Compost vs Store-Bought Planting Soil

This year, I thought I'd try growing some tomato plants in my yard. I've never tried growing tomatoes in earnest, but after visiting the Bartholdi Park Kitchen Garden in Washington, DC, I thought I'd experiment with some vegetables (yes, I consider the tomato to be a vegetable). Not only will this be a test of my gardening skills, but by happenstance, it will be a non-scientific comparison of homemade compost versus store-bought organic planting soil.

Newly planted tomato plant in my home garden

I planted two beds of tomatoes, three plants in each, on the same side of the house under similar lighting conditions. Both beds, filled with dense Virginia clay, needed soil amendments to improve drainage and nutrients. Since this experiment was an afterthought, it does not follow the true scientific method. If I were going to make fair comparison, I would have planted the same tomato plant types of the same container size on the same day under each of the two soil conditions. But since I didn't think about the soil comparison until after the fact, I planted different tomato plant types from different sized containers about five days apart.

Preparing the planting bed by digging out the clay soil

Amending the clay soil with an organic planting soil to improve drainage and nutrients

Still, the experiment has some value. My main goal is to get a general idea of how my free, backyard compost made mostly of dried oak and maple leaves stacks up against a store-bought, blended, organic planting soil. If my compost fares pretty well, then that is worth knowing.

The Planting Beds

Bed One

Soil:
Mixed the existing Virginia clay and top soil with my backyard compost

Plants:
1 Cherry, determinate, 2.32-quart container
1 Roma, determinate, 2.32-quart container
1 Bush Early Girl hybrid tomatoes, determinate, 2.32-quart containers

Date Planted:
June 15, 2019

Bed One: Virginia clay soil amended with homemade compost

Bed Two

Soil:
Mixed existing Virginia clay and top soil with store-bought, organic planting soil

Plants:
2 Husky Cherry Red, Hybrid, indeterminate, 19.3-oz containers
1 San Marzano, Heirloom, indeterminate, 19.3-oz container

Date Planted:
June 20, 2019

Bed Two: Virginia clay soil amended with store-bought organic planting soil

The new plants were treated to a steady evening rain. Stay tuned for updates to this post. Perhaps next year, I will do a true, apples-to-apples comparison. But in the meantime, may the best soil win!

End of Summer Results

Both sets of plants performed remarkably well. I had fresh tomatoes of one variety or another most of the summer long. They were fresh and delicious, and made the best tomato sauce I'd ever eaten! I did not prune or feed the plants, and I barely watered them. We had an unusual amount of rain and many days with mild temperatures that made watering almost unnecessary.

Tomatoes grown in homemade compost in early August

Tomatoes grown in store-bought compost in early August

Tomatoes harvested from my garden in late September

Because of the different types of plants, it's difficult to say which set performed better. I did notice blossom end-rot on a couple tomatoes in the homemade compost bed, and slug damage on the store-bought compost bed.

The red tomato has blossom end-rot

Tomato on the vine eaten by a slug

By the end of summer, both sets of plants had grown too tall for their cages. All in all, I can safely say that my homemade compost is worthy of using in my vegetable garden. Now I just need more of it!