Biochar Results: Mixed

Biochar

Image: Wikipedia.

Results from the first ever scientific study of biochar by researchers at the University of Southampton have been released. Plant growth was stimulated (up to 100%!) but,

the positive impacts of biochar were coupled with negative findings for a suite of genes that are known to determine the ability of a plant to withstand attack from pests and pathogens. These defence genes were consistently reduced following biochar application to the soil, for example jasmonic and salcyclic acid and ethylene, suggesting that crops grown on biochar may be more susceptible to attack by pests and pathogens. This was a surprising finding and suggests that if reproduced in the field at larger scales, could have wide implications for the use of biochar on commercial crops.

The researchers concluded:

Our findings provide the very first insight into how biochar stimulates plant growth — we now know that cell expansion is stimulated in roots and leaves alike and this appears to be the consequence of a complex signalling network that is focused around two plant growth hormones. However, the finding for plant defense genes was entirely unpredicted and could have serious consequences for the commercial development and deployment of biochar in future. Any risk to agriculture is likely to prevent wide scale use of biochar and we now need to see which pest and pathogens are sensitive to the gene expression changes.

Thanks to Michael Tortorello for the tip.

What is that black and orange bug in my garden?

4 bugs

The suggestions on a recent “what’s this bug? post on this blog made me realize how hard it was to tell apart several common garden bugs: the harlequin bug, the bagrada bug, the milkweed bug and the boxelder bug. They are all flattish, orange/red and black, under an inch long, and seem to always be mating.

After doing the research, I really wanted to see all the bugs side by side, so I made this picture and this simple reference chart. It is now my gift to you. You are welcome.

Continue reading…

Mulch Volcanoes: Another Bad Gardening Idea

Root Simple reader Donna, in response to my post on decomposed granite as mulch, alerted me to a related phenomenon: the infamous mulch volcano. For whatever reason, I don’t see this viral gardening phenomenon much here in Los Angeles but it’s really common elsewhere in the US.

Mulch volcanoes are generally considered to be a bad idea. It’s thought that the lack of air circulation at the base of the tree can lead to disease problems and you don’t want roots to grow up into the mulch so close to the trunk. When applying mulch you should keep it a few inches away from the base of a tree.

herber bayer grass mound

Artist Herbert Bayer’s EarthMound, 1955. Image: GardenHistoryGirl.

How strange gardening practices, such as mulch volcanoes, get started is really interesting to me. Mulch volcanoes remind me of miniature versions of minimalist art earthworks or Native American mounds. Is the mulch volcano a kind of outsider landscape art? Is the mulch volcano a misguided attempt at putting a human imprint on nature, what landscape architects call “clues to care?”

Decomposed Granite as Mulch: A very bad idea

Decomposed Granite

There’s a well defined architectural vocabulary house flippers use in our neighborhood. Flippers buy a crumbling 1920s bungalow, paint the front door orange, add a horizontal fence, redo the interior in a Home Depot meets Dwell Magazine style and then turn around and sell it for a million bucks.

When house flippers tackle a yard they tend towards the “low-maintenance” landscape (in quotes because there’s no such thing as a low-maintenance garden). One of the favorite tools in the flipper landscaping toolbox is decomposed granite (DG) used as a mulch. Put some plastic landscape fabric down (blocks rainwater in our climate, fyi) and top that plastic with DG. They then punch some holes in the DG/plastic and pop in succulents and maybe a rosemary bush or two. By the time the yard becomes a sad, desertified tangle of unhappy succulents and crabgrass, the flippers are long gone.

I’ve got a big issue with DG as mulch. In order for DG to look good, it’s got to be compacted and soil compaction is really bad for plants, including hardy natives and succulents. It stifles the life of the soil, and does not build new soil. And eventually, the plastic will fail, and the weeds will come through (some come through even when the plastic is new), and whoever is left holding the bag a couple of years down the road will be pulling decaying bits of plastic out of their garden for evermore.

What’s a better approach? Wood chips. Pile it on thick. Skip the plastic liner. Eventually your new plantings will cover any bare areas if you space them correctly. It looks good,  and the mulch breaks down and turns into soil. You will still need to weed but that’s called gardening. Save the DG for walkways. Or use mulch on your walkways too. Mulch is free or low cost. Just ask your local arborist to drop off a load.

From the Archives: Loquat Leather

loquatleather

Judging from the reaction to Mrs. Homegrown’s post yesterday it looks like some folks have a loquat obsession. Welcome home brothers and sisters.

At the risk of tooting my own loquat horn and repeating an old blog post, Mrs. H neglected to mention my controversial 2012 loquat leather experiment and recipe. You’ve still got to de-seed the damn things but at least there’s no need to skin them. Plus it makes use of booze.

I’ll admit it’s not a thrilling fruit leather but it’s not too bad.

Mrs. Homegrown chimes in:

My philosophy is simply that if one is going to go through the trouble of making fruit leather, preserves, pies etc., one should use outstanding fruit. The flavor tells in the end. After all, the starving times are not upon us. Even Erik can’t get super excited about this fruit leather–as I recall it tasted mostly of lemon and booze.

Then again, some people may have outstanding loquats–it sounds so from the comments on the last post. The ones we have access to just aren’t fantastic for preserving–too watery, too light. I just learned that there are over 800 cultivars of loquats, so there’s going to be lots of different loquat experiences.