We have been experimenting with Biochar as a soil amendment over the last few months and today we have set up a pot trial to test germination rates and growing rates for three different mixes and for three different brassica plants: Kale, Cabbage and Mibuma. 15 seed pots in total
B1 = Mix of coir and perlite with a this topping of vermiculite
B2 = Mix of coir and perlite with approx. 1/3 by volume biochar. We made a batch of biochar on a burn at Pen Dinas in June as part of the PDC course we were running at the time. Also topped with a this layer of vermiculite. 12 pots in total
B3 = We used the same I mix as above but extended the mix with more coir and perlite to make 18 pots in total. Also topped with a this layer of vermiculite.
All the pots have been placed outside and will be treated exactly the same. We are specifically interested in germination success and rare, plant development and plant health. We will add a liquid feed to all the pots when they develop their first true leaf. This will be a nettle and comfrey ‘tea’ mix.
The other test is a straight growing test in 2 identical raised beds, one with the addition of 1.2 Kg of biochar, both have 1 wheel barrow of Cwm Harry compost added. They have been been planted with 9 Oca plants, at equal spacing.
Oca may not be the best choice of plant to get a clear result, but i chose it as it yields a tuber which is therefore very easy to measure and compare. Doing some simple growing tests has also taught me that growing test are difficult to do accurately, as there are so potential variables to eliminate.