Tomatoes: A not-so-scientific growing experiment. Week 1 update

Updated: 3 hours ago

We've started a summer and fall growing experience with Big Boy tomatoes to see if we can get some not-so-scientific insights about what compost / soil mix is the best for growing these tomato plants. Check out our first post.

Tomato plants in various amounts of compost and topsoil
Week 1 update: Compost / Soil experiment

Above: our 12 growing containers, each mixed with a different certified compost-to-soil ratio, located at our Balls Ford Road Compost Facility in Manassas, VA.


Over the past week, we’ve seen our first flowers and three of the tomato plants have started to have their first fruit!


To try and bring some objectivity to this, I’m going to try and capture three things to see how the different compost / soil ratios impact plant growth.

  1. Height of the tomato plants. Since they all started at slightly different heights, the change in height should be the most important.

  2. Number of tomatoes each plant produces during the season. I’ll have set pick dates (e.g. during measurement) to limit the subjectivity of when to pick.

  3. Weight of the tomatoes. This will hopefully give us an indication of the size of the tomato since each plant will be given the same amount of water and light.


Below are the results from the first week of growing. I think it’s still too early to determine any trends about which compost / topsoil blend is growing the best plants; we’re excited to see how things change over the coming weeks!


Plant 1:

0% compost, 100% topsoil

Height start: 14.5”

Height 7/1/22: 20”

Growth: 38%

There are two interesting things that we can observe with this plant. First, the soil doesn’t take the water in as quickly as the ones with compost in them (soil permeability). Second, the soil starts to crack as it dries out—a sign of relatively poor soil health. I’m surprised that the plant is growing as well as it is since the soil doesn’t have as much compost (and likely nutrients). It’s possible that the soil has enough of the nutrients that the tomato needs, and/or that the potting mix that the tomato plant started in has enough nutrients (for now?).


Plant 2:

10% compost, 90% topsoil

Height start: 16”

Height 7/1/22: 22”

Growth: 38%

This soil also cracks and pools a little bit during watering but notably less than Plant 1. It’s amazing how much just a little bit of compost makes.


Plant 3:

20% compost, 80% topsoil

Height start: 14”

Height 7/1/22: 21”

Growth: 50%


Plant 4:

30% compost, 70% topsoil

Height start: 14”

Height 7/1/22: 20”

Growth: 43%


Plant 5:

40% compost, 60% topsoil

Height start: 16.5”

Height 7/1/22: 22”

Growth: 33%


Plant 6:

50% compost, 50% topsoil

Height start: 16.5”

Height 7/1/22: 22”

Growth: 33%


Plant 7:

60% compost, 40% topsoil

Height start: 14.5”

Height 7/1/22: 21.5”

Growth: 48%


Plant 8:

70% compost, 30% topsoil

Height start: 13.5”

Height 7/1/22: 18”

Growth: 33%


Plant 9:

80% compost, 20% topsoil

Height start: 13”

Height 7/1/22: 19”

Growth: 46%


Plant 10:

50% compost, 50% topsoil

Height start: 15”

Height 7/1/22: 23”

Growth: 53%


Plant 11:

40% compost, 60% topsoil

Height start: 10”

Height 7/1/22: 13.5”

Growth: 35%


Plant 12:

30% compost, 70% topsoil

Height start: 10”

Height 7/1/22: 14”

Growth: 40%



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We make premium and local compost, mulch, and topsoil in Manassas, VA. They are specially designed to increase the health and productivity of our local soils, and with our focus on sustainable practices, this lets the environment and your garden grow good, together. We sell bulk and bagged compost, bulk natural mulches, bulk and bagged dyed mulches, and bulk topsoil.

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