By Terry Phillips
What does your garden have in common with Economics, Chemistry, Ecology, Technology, and Development?
Something called Limiting Factors. I just discovered that there is actually a LAW governing limiting factors of growth. It’s called “Liebig’s Law of the Minimum.” It states that it doesn’t matter how many resources you have available, your growth will be limited by the SCARCEST resource.
In the following essay, I’m going to outline how I decided which were/are the eight limiting factors in my own garden on Quadra Island, how they affect productivity, and how I attempt to overcome them to make more things grow better. You can hopefully use this as a guide to assess your own garden and give you some ideas.
The lay of the land is to the northeast facing the coast mountains, Read Island, and Mount Dougie Dowler. The garden is tucked into the base of Heriot Ridge on the east side of Quadra. All this means I am blessed with gorgeous views of the mountains, but the garden is also subjected to the cold continental outflow winds in winter. Heriot Ridge somewhat shelters the garden from the Northwest winds that signal a sunny spell in summer. The neighbouring properties directly protect my garden from all but the worst of the southeast gales of winter. But there is a tendency for the winds to bounce off the bluffs, swoop down, and push against fruit trees, brussels sprouts, or anything tall. The result of the garden’s elevation means I get frosts sooner and later than others, and more snow which takes longer to melt. (I know, it’s just up the road a bit….)
The result of this aspect and elevation means my garden has a later start date than the south end of Quadra, and a sooner end date, resulting in a shorter growing season. The third week of May to the beginning of September.
I can’t change either aspect or elevation. But I can mitigate this by creating microclimates.
- The long thick hedge on the east side slows the cooling winds and allows the air to heat up over the garden.
- A fence to the north and a building both create heat traps for early spring sunshine or ripening tomatoes.
- A greenhouse allows me to start and protect early crops.
- Plastic tunnels in fall and spring, remay covers for winter, bedsheets and black tarps to preheat the soil, are all things that I do to keep growing longer.
#2 Lack of Afternoon Sun
I bought this property in July when the sun was everywhere. I couldn’t imagine where the sun might be on the winter solstice.
(Here’s how, by the way: Add 23.5 degrees (Tropic of Cancer) to our latitude (50), subtract that from 90 degrees. = 16.5 is the angle of the sun here at Winter Solstice, more or less. Now you can stand out in your garden looking due south and measure 16ish degrees to see which buildings, trees, or mountains are blocking your sunshine. It might also be helpful to know how much sun you will get around the time of the equinoxes.)
A major factor blocking the precious sun from this garden is Heriot Ridge itself and the trees all around.
I’m never going to cut the trees down, and the bluff is staying put, that’s for sure. The lack of that afternoon sun means it is slower to ripen those heat-loving squash, tomatoes, and peppers. But a benefit is that cool thriving plants do well: brassicas, greens, and peas. I take advantage of the greenhouse, plastic hoops, cloches, and remay to keep the heat in where needed. Plastic juice jug cloches protect crops early and late in the season.
This garden was very slopey to begin with. The entire property is like an upside-down bowl. Water shedding in the extreme. I was prepared to wind my garden paths throughout, accommodating the slope. But too much slope is limiting in that it creates super drainage and the water disappears too quickly. Slope is also difficult to walk on or push a wheelbarrow around on. I still have some sloping pathways, but now at least the gardens are terraced.
For flower gardens, the terracing was done with hugelkultur beds (placing sticks and logs from property clean-up across the slope, then covering over with soil, chips, leaves, and sawdust). Rock walls hold up the low sides.
For the vegetable beds, just soil was used to create the terraces. Lonicera (honeysuckle box) or Buxus boxwood hedges hold up the low sides.
The soil depth on the low side has increased over the years from one foot to two feet deep on the low side. The hedges just grow taller to accommodate the extra depth.
I want to say a few words about using shrubs as an edging for a raised bed since it’s not common to see. Box Lonicera is from the honeysuckly family, and would form a lanky shrub if not pruned regularly. I find Lonicera to be an excellent hedge material for this purpose for these reasons:
- It’s less expensive and easier to use than wood, rocks, or concrete.
- The roots are not invasive.
- The plant is dense enough to hold the soil, provided you shape it with pruning.
- The plant grows quickly and is vigorous enough to require pruning 3 – 4 times a year, providing nice tender green tops for mulch or compost.
- The plant gives back in another way too: Provided you didn’t prune the flower buds off in May, it blooms profusely in May at the same time as some apple trees. There are thousands of bees enjoying the nectar from the tiny yellow flowers hidden in the foliage of 3 long hedges.
- Lonicera is incredibly easy to start from 4” cuttings.
- Other than what it steals from the vegetables, the hedge gets no extra water or fertilizer.
There are a few drawbacks too:
- Extreme winter cold may cause some die-back.
- Heavy snow can cause it to flop over temporarily.
- Slugs will find a home here as they do everywhere.
An advantage I have with my sloping garden is excellent drainage for fruit trees. There is not a soggy bottom anywhere.
This garden site was logged prior to my purchase, so I inherited stumps. Initially, I was going to wind my way around and through them. (Basket on arm, head in clouds – so romantic – but impractical.) Can inefficiency be a limiting factor? I’ll say yes, it can. So the stumps were pulled and left as habitat in another area, away from vegetables and fruit trees. This allowed me to create a garden with straight paths, crossroads, and ease in planning rotations, planting, watering, and harvesting.
To be continued…
Find Part 2 HERE
Love of the outdoors, nature, and fresh food guides Terry Phillips’ garden project on Quadra Island.