By Terry Phillips
In Part 1, I outlined four limiting factors in my garden on Quadra Island, how they affect productivity, and how I attempt to overcome them to make more things grow better. Now in Part 2, I will cover four more limiting factors. I hope that you can use these two blogs as a guide to assess your own garden and give you some ideas.
#5 Rocks/ Lack of Soil
What did I expect for the base of rocky bluffs? There is no such thing as digging in some of this ground, it is just broken rock all the way down. Moving further away from the bluff there are boulders, easing to cobbley gravel and hardpan. I can see how the glacier carved through here, smoothing bedrock and depositing erratics like granite boulders from who knows where. Cobble, sandy gravel, and silt packed to hardpan have been left during its ebb and flow through the millennia. This has been difficult to turn into soil.
About 6 tons of rocks were removed, mostly by hand, the larger by machine (it helps to be married to an Excavator).
The build of soil started with truckloads of alder bottom from another person’s pond digging. (Alder bottom is the area where alder trees are currently growing in a natural land basin. The leaves get deposited for many, many years and the soil builds up.) There were sticks and rocks to pick out, but it was worth it. The fill was spread over my garden site to a depth of about four to eight inches, helping to level out the uneven gravelly ground, and giving me a head start to a productive garden.
Keeping the garden continually growing things adds to soil volume and structure over time. Growing plants add root exudates (sugars and nutrients that feed soil microbes). I am a gleaner of organic matter.: leaves, sawdust, bark, wood chips, grass, and seaweed. I add a bit every year. Now I am approaching 2 feet of soil where I once had 8 inches!
#6 Lack of Water
Did I mention that this is a water-shedding site? Add incredible drainage too, even in winter. It is never boggy. In addition to this extreme drainage, there is a lack of water in the ground – the well has enough to run a household but not enough to garden. I have calculated that this garden could use up to 20,000 gallons throughout the season, but I manage on 10,000 gallons. I have tried catchment off a roof into barrels (not enough by far). I currently use a 2000 gallon tank (needs to be filled at least 5 times). The best solution would be to build a reservoir holding 20,000 gallons and feed it from roofs in the winter months. That’s a big project that hasn’t happened yet.
I start by mitigating water loss:
- I keep a mulch over the soil to reduce evaporation.
- I add water-retaining elements, like clay and organic matter.
- I ration water. Rationing my water use is a constant trial.
- I plant into depressions and trenches (the opposite of raised beds). For example, a broccoli start will go into a basin dug about 6” deep and 12-18” across. The water is contained right where the plant needs it. These basins also provide shelter during cool months or hot days.
- I ration water, oh I said that. I water using drip lines and timers during the cool mornings or evenings.
- Some plants do without water, like flowers, and it is rare for even fruit trees or berries to get water.
When it rains in the summer you can hear me rejoicing.
Acidity, major elements (NPK), microbiology (bacteria, fungal networks), soil structure, and minerals are all factors related to each other. Whole books are written on the subject.
You might not know which of these is limiting in your garden so I would recommend a soil test (call Ryan Nassichuk if you live on Quadra).
The rains here do leach out water-soluble nutrients and acidify the soil. I use compost, mulches, and manures, and make my own organic fertilizer mix for planting time. I add dolomite lime to the vegetable bed (except where potatoes are to grow).
I could do some more work to find out which of these nutritional factors was the most limiting. In the meantime, I go by my belief that I’m unlikely to over-fertilize if I’m using natural organic matter.
I use my organic mix at potting-up time, and again at transplanting time (a shovelful forked gently right into the planting hole).
To see the recipe for my organic mix, CLICK HERE and scroll to the bottom.
This paragraph is as equally about Balance as it is about Pests. Become an observer. Spend time watching the predatory wasps, ladybug larvae, spiders, beetles, snakes, lizards, and birds control your pests for you, and do what you can to make these helpers welcome.
These are the pests that I have the most trouble with: slugs, wood bugs, slugs, white-crowned sparrows, slugs, robins, towhees, and slugs. Limiting, yes, when all the strawberries disappear, or the carrot seedlings get mowed down by wood bugs, or the cabbages devoured by white-crowned sparrows. Know that everything you grow will be ravished unless you protect it.
Deer fencing is a must, do it once and do it right. I’ve rarely had a deer inside and it was always my fault, not the deer’s.
Robins are the next most easy to control – netting over berries. It also helps to have lots of native food for them. I never had a problem until the local patch of salmonberry died. So do plant salmonberry and saskatoons outside your garden.
White-crowned sparrows are a problem in April when they fly through, ravenous. If you don’t cover it, you’ll lose it. They really like dandelion heads, I’ve noticed, so leave some for them and maybe they’ll leave your cabbages alone…. Remay and jugs over everything.
Slugs are a constant battle, but battle you must do. Cover early crops with juice jug cloches pushed well into the ground. Check them daily for slugs that might climb in. I pick morning and evening once slugs become active (April, May, June) and then every time it rains all summer, especially the grassy areas where they hide.
Slug traps – I like leaving piles of weeds, dandelions, and grass trimmings every so often. Check these traps twice a day for slugs. Not so much of a problem once the plants get bigger. I don’t use slug bait.
The trick is to get the slugs early in the year before they reproduce and lay hundreds of eggs. Toss your mulch about to expose slug eggs so the birds can get them. Nurture a rock pile habitat for snakes and lizards. Fresh sawdust pathways around the vegetable beds (which are away from grassy areas). Fresh sawdust pathways are not comfortable for slugs to travel across. So a topping every year is usually in order. It becomes easier to spot them as well. The veg garden is 100% surrounded by sawdust pathways, keeping it separate from the grassy areas. Some slugs overwinter in the garden mulch, or eggs have become deposited when I wasn’t looking. I used to give slugs flying lessons but now they get the quick snip.
Over the years I have had less of a slug problem.
Wood bugs (sowbugs/pillbugs) can decimate anything direct seeded into your garden, especially carrots. The best I can suggest is to make sure there is nowhere for them to hide – no wood, no mulch, no rocks – until the carrots are bigger, and then you can put the mulch back. I’m not sure about diatomaceous earth for wood bugs because it will kill any insect that comes into contact with it. I tend not to use it.
Minor pests like aphids, flea beetles, and carrot fly I’m still learning about. I suspect the secret will also be about “balance” in the garden environment. I’m going to learn more this year about the predators of these pests, companion planting, and other tricks to limit their damage.
Love of the outdoors, nature, and fresh food guides Terry Phillips’ garden project on Quadra Island.