Potting Mix Trials Update

  • Easy As Organics Water Only Soil vs Commercially Available Certified Organic Potting Mix

Plants grown in biologically active soils exude compounds from their roots via photosynthesis to attract microbes into the rhizosphere in exchange for the nutrients it needs. The more diverse a soil microbiome, the more effective this natural process is. This is very different to a conventional approach where the grower will be the one responsible for providing nutrients in ionic form to the plant directly via a liquid solution. I hope that this trial will demonstrate clearly the true nature of living soils in action when compared with a regular organic potting mix that can be found in any local nursery or department store.

The hypothesis:

Plants grown in Easy As Organics Water Only Soil will out-perform a commercially available certified organic, certified to meet Australian standards for compost (AS4454) potting mix. The performance will be noticeable in the later stages of vegetative growth towards flowering and especially in yield and quality.

The label on the commercially available potting soil product claims to be a rich organic potting mix with enough nutrients for 3 months of healthy plant growth.

The methodology consists of 4 plants, each growing in a 45L container inside a 1.2 x 1.2m growing tent. An extraction fan was installed to pull fresh air via a centrally located vent at the bottom. A single 315w ceramic metal halide lamp mounted in a reflector at the top of the tent with a light cycle of 15 hours on and 9 hours off will provide wide spectrum lighting.

Plant variety is Purple Ghost Chilli from a renowned chilli breeder. Seeds were propagated in a seed raising mix containing 80% peat, 10% aeration, 10% worm castings and amended with lime and kelp meal. 4 seedlings with the most similar characteristics were planted in each 45L container. The 2 growing on the left is growing in Water Only Soil and 2 on the right is Certified Organic Potting Mix (un-named)

An automatic, gravity fed Blumat system was installed. Rather than introducing a variable by hand watering, plants are only taking what they needed based on soil requirements.

 

Day 22 from transplant. Water Only Soil (living soil) on left, commercial potting mix on right.
Day 49 from transplant. Water Only Soil (living soil) on left, commercial potting mix on right.

It should be noted that temperatures have been very cold and are contributing to the slower rate of growth. I placed a gentle greenhouse bar heater to take the chill off.

Living soil on the left is clearly ahead. I was not expecting this dramatic of a result so soon in the trial. Both potting soils and leaf tissue samples will be sent to a lab for analysis at the end so we can have more data to help make sense of the results. Hopefully the experiment can help those looking for higher performing soils containing better ingredients but are perhaps hesitant to spend extra money. Stay tuned for updates and a time lapse video at the end of the trial!

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