Gardening Mistakes: Six Ways We’ve Killed Plants

betony

In the years we’ve gardened we’ve killed our share of plants. I’d like to think we’ve learned from our errors. To that end, I thought I’d run down some of the big mistakes we’ve made.

1. The right plant in the right place Our front yard is a hillside. Our backyard has two tall trees that cast shade towards the north. The soil varies in color, texture and quality largely due to almost a hundred years of construction projects (decks, foundation work terracing, etc.). The same plant that might thrive in one spot will wither in another. This is where trial and error comes in. Sometimes the only way to find out if what will grow is to plant stuff and see what takes off.

2. Soil compaction This is a big problem in urban areas and our yard is no exception. The parkway, which gets a lot of foot traffic, is very compacted. Very few plants do well with compacted soil, including natives. The best way to break up compacted soil is with a broadfork, a spendy item. We use a garden fork instead.

3. Soil fertility When it comes to growing vegetables, in particular, you need rich soil. Get a soil test first. But soil fertility is a lot more than chemistry–it’s about life. Healthy soils have a rich and diverse microbial and fungal ecosystem. You can jump start that fertility with compost. But somehow we never have enough compost.

4. Bad nursery stock. I’ve bought my share of root bound plants and plants that came with diseases. The worst example I’ve seen is a nursery selling grape vines that all had incurable Pierce’s disease. That’s a guaranteed failure. Thankfully we’ve found a few good sources when we need seedlings: Annie’s Annuals and Perennials and Theodore Payne.

5. The great mystery of watering. I’m still working on this one. I discovered last year that I’ve been under-watering our fruit trees.  To figure out watering needs for fruit trees the pros use expensive soil augurs to take samples. I may break down and get one but in the meantime I’ve got a high quality moisture sensor I’m experimenting with on the suggestion of fruit tree guru Steve Hofvendahl (thanks Steve!). More on this topic in another post. I’ve also been known to neglect and/or over-water our vegetables as well.

6. Timing. It took us a few seasons to realize that our Mediterranean climate is very different from what the back of seed packages were telling us in terms of when to plant. I’m sure climates that have hard freezes have a whole other level of surprises and heartbreak.

Acceptance
You’re going to kill plants. Just as you have to break an egg to make an omelette, the only way you’re going to learn about your garden, its soil, microrclimates and quirks is by killing plants.

I’m sure I’ve left some things out.  Let us know in the comments how you have killed plants.

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.