Do Rock Dust and Biochar Improve your Garden’s Yields?

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Today we are going to finish up harvesting from our trial beds and take a look at this years results. If you remembered at the beginning of the season we filled all three trial beds with the exact same soil with the exception adding charged biochar to one and rock dust to another leaving the third as the control. The Hypothesis we are testing is that both products claim to benefit our garden plants which should result in increased production of produce.
We planted the exact same varieties of plants in the same location in each of the beds and made sure to treat each bed the same.

All year we have been harvesting from the trials weighing the produce in grams and noting down the totals. Today we will share the final results from my garden and at the end we will convert the grams into pounds for your reference.
The kale and tomato results we published in the last trial update. Here is the final summary showing the control leading followed by the Biochar bed and further behind the Rock Dust.
Today we finished harvesting Peppers, Carrots and Mangel Beets
The peppers were collected as they became ripe and when frost threatened we collected all of them. The Biochar peppers were not only had the largest single pepper at 120.5 grams but the total was the highest with 16 peppers at 1021 grams. The control offered 11 peppers at 895.5 grams and the Rock Dust far behind with 7 peppers producing 533 grams.
This brings our total yields to have the control leading with 6721.5 grams the biochar with 94% of the yield of the control at 6368 and the rock dust trailing at only 4894g or 72.8% of the yield at when compared to the control.
It was then time to harvest our root crops. The carrots were planted using strip tape as the seeds are extremely small. In order to standardize the results the average number of carrots was calculated at 34 and the average weight in each trial bed was calculated. The corrected number was then added to the totals. In this case the Rock Dust lead with 1802 grams followed by the control at 1397.4 and the biochar quite far behind at 588.7 grams.
The mangel beets were harvested and the greens and root were weighed. Much like the carrots the Rock Dust lead with 3734 grams but the biochar came in second with 2944.5 grams and the control trailed behind with 1922 grams. In retrospect mangel beets seem to have higher variability in the size of the root and low total number of beets makes it tough to say if the large root size in one bed is as a result of the additive or simply chance.
The final Alberta Urban Garden year 1 trial harvests are as follows.
Rock Dust with 103% of the harvest when compared with the control at 10,430 Grams or 22.994 pounds
The Biochar with 94% of the harvest when compared with the control at 9900.7 grams or 21.82 pounds
The control ended with 10,040.9 grams of harvest or 22.14 pounds.
This years results in my garden are inconclusive. Overall the Control had the much more stable harvest where as biochar and more so the rock dust had variable harvests dependent on the crop. It is not important to submit the results to both Patrick and I if you are participating. The combination of the results will help weed out individual gardens statistical anomalies such as what we suspect as the chance size differences in the mangel beets.

This represents a difference of rock dust having 390 grams more produce or 0.85 lbs and Biochar having 140grams less or 0.3lbs then the control. These results dont represent a significant enough change to determine if rock dust and biochar increase the yields as our hypothesis states

Based on the results from this years trial we are likely going to continue to a 2nd and 3rd year in order to further understand the impacts of Rock Dust and Biochar on our home gardens.
Following the response from the great gardening community and our natural urge to find out more we are going begin attempting to analyze these results further. Starting with investigating simple tests such as the Brix Tester or Refractometer and moving into more accurate soil and tissue sampling at an accredited environmental laboratory. We hope to see if we can understand how these products influence the soil and produce in the first year of the trial and potentially track the results over time.

About Stephen

The Alberta Urban Garden Channel hopes to promote organic gardening that is simple, sustainable and does not have to cost a lot. We do this by investigating the Science behind gardening, methods, practices and products to make sure that you will have the best chance of successfully growing your own food at home.