Biochar, our new trick in the garden

As is usual for us at this time of year, we're spending a bit of time cultivating our future food. Often I think about how much we get from our garden for the time we put into it. For days or sometimes weeks we'll do nothing but harvesting - these days we are gathering lettuce, zucchini, herbs, kale, peas, some carrots and a disappointing few, but delicious, strawberries. (Broccoli, cabbage and cauliflower will come in next week.) Then we have spurts of energy in there, and work hard for an hour, or two or three, sometimes day after day.

Biochar: it's for real

I'm always on the lookout for promising new ways to make the garden easier/better/more productive. One idea that's intriguing me and my fire-loving husband is biochar. Biochar is this: chunks of charcoal, preferably pea-sized, that have sat around in compost for a while before being incorporated into the soil.

The magic of the stuff is this that it locks up carbon in the soil (in the form of burnt wood), and is an excellent storehouse for two vital soil elements, microbes (sourced from the compost) and water. These goodies are housed in the charcoal's hollow channels that were originally the vascular structures in the tree that was burnt.

I keep reading about it in slightly alternative magazines, but please don't make the mistake of putting it in the same category as aerated compost tea or burying stuff in cattle horns (my apologies if I'm mistakenly putting those in the loopy category). This is a real thing - Massey University even has a research centre looking into it. Here's an 11-minute interview with one of the researchers.

How to make it

Note that this is a very down-home method. If you've listened to the interview in the link above, you'll realise that this method is very crude! For example, there are optimal temperatures at which to make the charcoal, and we have no idea how hot our fire gets.

1. Burn some wood incompletely to make charcoal (my husband does this as we sit around a fire that makes an ugly bald patch in our lawn - but it's worth it and is always a social occasion). Burning prunings is a good way to use them up. We put the chopped-up prunings in old milo tins with holes bashed in the lid. Another way to do it would just be to turn the hose on the fire while the burnt wood is still in lumps, before it burns away into ash.

Us with neighbours around a fire.

Milo tins, collected from a workplace tearoom

2. Once the charcoal is cool, it's ideal to crush it up into pea-sized chunks. We haven't done a lot of that because it's probably a horribly dusty process. We might sort out that side of it out one day, though. It tends to break up quite small during the composting process, anyway.

3. Chuck it in the compost heap or bin.

4. Distribute the compost in the garden once it's ready. The biochar chunks will be strewn throughout the soil.

I saw a weed growing out of a piece of biochar in the garden today. I'm not sure what that proves, but it seemed proper! There is good stuff in that there biochar!

Splashes of colour

Our garden's doing really well so far this year. It's the tomatoes, beans and cucumbers I'm looking forward to most.

(Plenty of garden photos here - scroll down if you just want more words!)

Climbing beans

Rampant tomato plants with NZ spinach in the foreground

Little carrot seedlings

A cabbage awaits harvest

The tomato garden from the other side

Most of our tomatoes are black - although they're supposed to be
yellow underneath and dark red on top. They're  'Eclipse Fireball'. 

Will the broccoli be ready before Christmas?

A zucchini plant happily feeding from the compost bin next to it

In the meantime, we have plenty to eat, and I'm loving the splashes of red in either corner of the garden: red alstroemerias flowering in one corner, and chickens with red combs in another. One fills the vase, the other fills our bellies in the form of eggs, and they both fill my eyes with beauty and my soul with happiness.

Ironically, I nearly lost one to the other shortly after I brought the baby alstroemeria plant home from a church fair. Chickens love alstroemeria leaves!