This final instalment of the series builds on the valuable information presented previously. It offers a succinct summary and a tool kit for adaptation to the changes we all see in our gardens. 

The reality of climate change became glaringly obvious in 2021 when records were set in BC’s lower mainland for heat, drought, rain, and cold, all within six months between June and December. Much like the rest of the world, Canada is seeing increasingly frequent, and rapidly fluctuating, weather patterns with extended periods of previously unknown extremes.

Globally, plant hardiness zones are shifting from the equator toward the polar regions, threatening localized extinction, causing species migration, and redefining what is native. 

This of course has profound effects both on natural ecosystems and all things agri- and horticulture. Summers on average may get warmer and longer, but on the flip side, this means disruptions in plant growth and bloom cycles, affecting pollination, and producing more generations of some plant-feeding insects. We are also losing growth days to both cold spells and heat waves.

Meanwhile, prolonged cold and wet conditions in spring can lead to reduced pollination and crop failure. Low temperatures also inhibit soil biological activity and plant nutrient uptake. Waterlogged soils are tough on microorganisms and plant roots alike; later on, these plants are more vulnerable to drought, and more susceptible to root disease and blowdown.

Resilient Gardens

So how do we adapt, how do we build resilience to keep gardening and especially growing food?

To start with, choose tough, proven, disease-resistant species and varieties; this is not the time to test the limits of hardiness. Plant more perennials, both ornamental and food crops, along with traditional annuals. It helps if they have low summer water requirements. Fruit trees for the future are late flowering and possibly self-fertile.

Grow several different varieties of any one food crop for redundancy; if one type struggles or fails by mid-summer, rip it out and plant something fast maturing in its place (40 to 60 days to harvest). Some veggies are biennial and can be overwintered; they tend to be very successful in their second year.

Learn to save seeds, and adapt seeding and planting to the weather. In a cool spring, wait for the soil to warm to 15 degrees C; if it’s very warm in early to mid-summer, sow a little deeper and cover or shade the seed beds. Whenever feasible, plant trees and shrubs in the fall, with the longest possible period before the next drought, and be prepared to give supplemental water during the first couple of summers.

In the ornamental garden, rethink the use of “thirsty” staples like hedging cedars, hydrangeas and rhododendrons. Native plants are tough, although not all native plants are drought tolerant; conversely, many non-native plants can be appropriate if they blend harmoniously into the garden ecosystem. 

To reduce lawn watering needs, leave the grass to grow long, and mow in sections. You do want to water the lawn, moderately, mainly to keep the soil ecosystem underneath alive. 

Tool Kit for Resilience

Extreme heat:

Watch the weather forecast and be ready to step in quickly. In a heat wave, provide shade to the garden during the hottest hours of the day. Spray water mist for both cooling and moisture. Plants can cope, to a point, with high temperatures or dry conditions separately; it’s the combination of heat and drought that spells disaster.

You can invest in fancy shade fabric, or improvise with bed sheets, tablecloths, lace curtains, wooden lattice frames, or wicker fence panels. Be sure you can adequately vent and shade the greenhouse or tunnel. Heat kills; shade merely slows down growth.

Extreme cold:

By contrast, expect colder, longer Arctic outflow events in winter. Greenhouses, cold frames and cloches help extend the season or weather sudden cold spells. Stay alert for late spring frosts, and cover tender seedlings with tarps or plastic sheeting if needed. It’s better to lose a few to reduced light than all of them to a hard frost.

Wind storms:

Storm and wind proof the garden by removing vines off trees (vines increase wind sail and snow load), pruning climbers hard in the fall, and providing sturdy permanent plant supports. Also consider adding structural elements such as hedges, windbreaks, walls and fences to create smaller, more sheltered garden rooms. But remember, food gardens need at least six to eight hours of full sun every day.

Heavy rains:

Prepare for heavier rainfalls. If areas of the garden are waterlogged, explore drainage or diversion options. Winter veggies and permanent crops like strawberries are better off in mounded or raised beds. Conversely, experiment with slightly sunken beds for summer growing.

Drought:

Of course, also plan for drier summers; perhaps consider a low-volume irrigation system. Better yet, find creative ways to capture and use rainwater and household grey water. Invest in self-watering containers if your garden is on the deck, balcony, or rooftop.

Resilient Soil: 

All of the above goes hand in hand with year-round mulching, both with cover crops and with traditional mulching materials, especially leaves and plant residue (“chop-and-drop” a crop, flower, or weed right where it grew). Remove mulch only briefly in spring to allow seed beds to dry and warm up. Stockpile bags of dry leaves in autumn for use the following summer. 

Keep building soil biology and organic matter content. As much as possible, minimize soil disturbance. With intermittent “feast and famine” cycles of precipitation, our greatest water (and nutrient) storage system — even more than rain barrels and cisterns — is the living, breathing, well-structured soil.

Biodiversity:

Above all, plant more plants: Trees to capture and store carbon above ground and below; climbers and ground covers for multi-storey landscapes; more native plants best adapted to local conditions. Make a generous allowance for a diverse range of wildflowers and even weedy volunteers to support the all-important wild pollinators. Finally, have some fun going all out and planting more densely than you ever thought possible. 

Re-examine your relationship with animals, especially insects. Even those we call “pesky pests” exist for a reason: They have a job to do. It is our job to find out their functions in the ecosystem. 

To Sum Up 

Notice how a lot of the tips for developing climate resilient gardens are the same as those we are teaching in the Organic Land Care curriculum? Build soil. Mulch. Plant in layers, and densely. Save seeds. Use water wisely. Grow biodiversity. And remember to share your success stories with other gardeners!

This blog was edited from its original published version at Organic Gardener’s Pantry. 

Written by Christina Cook