The results to date have been both surprising and unsurprising.
Overall, the BioGro Premium Wicking mix is performing the best. The 3 Jeffries beds are not far behind. The 3 sandy loam/compost blends haven’t performed nearly as well as I had predicted.
The seeds in the BioGro and Jeffries beds were the fastest to germinate. The pak choi, romanesco and lettuce were thinned out to a single seedling per bed.
The first harvest were radishes in only 25 days from sowing seeds which was amazing. As can be seen from the picture, the radishes in the BioGro bed were slightly larger than the Jeffries beds with added Culchar or Rooster Booster. The straight Jeffries bed was harvested of radishes on Day 43. Beds 2, 6 & 7 have not had the radishes harvested.
There are significant differences in growth between the duplicate beds which is quite surprising. I initially put that down due to insufficient mixing of the soil but the BioGro soil comes out of a bag.
The pak choi, lettuce, basil and coriander are ready to be harvested, a few leaves, from many of the beds (BioGro and Jeffries).
The beds that have had the radishes harvested were replanted on Day 45.
The original aim of this trial was to see which soil performed best in a wicking bed. After a month I starting thinking about how I was going to add fertiliser to the beds in an equitable fashion and with the 3 Jeffries beds comparing fertilisers this was going to be tricky. So I changed the aim. What I also wanted to know was just how many nutrients each soil type had and the simplest way to assess this was to add no fertiliser at all to the beds during the growing season. At some point, it was highly likely that the soils would run out of nutrients and that would be obvious by the change in plant health/growth.
Rather than pick the pak choi and lettuce a leaf at a time as I normally would, I removed the plants in their entirety when they were ready to harvest to give the remaining plants, particularly the Romanesco, some nutrients to be able to grow.
What I didn’t expect was for the success of the soils thus far to completely change. As reported above, at Day 45, BioGro was the clear leader followed by the Jeffries blends. This changed as it was the Jeffries soil blends that ran out of nutrients first. This was shown by the slowing of the growth of the Romanesco to the point where it stopped and then started producing the head/floret which instead of forming the typical head that could be harvested and eaten, went to seed immediately. The sandy loam/compost blends (#2 and #6) rapidly caught up and overtook the Jeffries blends and were only slightly behind the BioGro soil. Soil #7 did overtake the Jeffries blend but was slower than #2 and #6.
In the end, only 1 of the 14 Romanesco plants was able to produce a head that could be harvested and it was very small. It came from a BioGro bed (Soil #1).
The final conclusion to this trial is that none of the soils contained enough nutrients to grow the plants in this trial. This could be partly due to the overplanting that I used and often use and get away with in wicking beds. But it does give a fair indication that all the soils needed extra nutrition as some point during the trial, some more than others. So whilst on the face of it, the Jeffries blends performed the worst, this is not how I would normally run a garden bed nor would I recommend anyone do this. Regular supply of nutrients in the form of slow release, organic (or not) is needed to keep vegie plants growing and producing. For plants with lower nutrient requirements such as small leafy greens (lettuce, baby spinach), spring onions and herbs, you can get away with not adding much extra nutrients after planting as long as you have a good supply of nutrients in the soil. For the hungrier plants such as brassicas (cooler months) and tomatoes (warmer months), extra nutrition is a must.
The next soil trial is about to start and will be done with regular supply of nutrients. I’m growing cherry tomatoes ‘Tommy Toe’ and have reduced the number of soil down and will be testing a couple of new and yet to be released soil additives.