Each year, regular summer rain seems to be less frequent than previous years. Rainfall, or more specifically the groundwater that is replenished by the rain, is so important for the health of our ecosystems and for the maintenance of the water cycle. The changing climate is having an impact on water systems. Rain is less frequent, and when it comes, it is often very heavy.  

According to Agriculture Canada, as of September 30th, 2025, there were still many areas across the country classified as severe, extreme or exceptional drought with many identified as long-term drought (https://agriculture.canada.ca/en/agricultural-production/weather/canadian-drought-monitor/current-drought-conditions). Life is not sustainable without water, but we no longer have a reliable water cycle to sustain the moisture levels our ecosystems require. When soil dries up it can no longer support vegetation and microbial life. As such water is more likely to run off than infiltrate the soil, exacerbating conditions for flooding, erosion and a continuing cycle of ecosystem damage. 

Dealing with droughts and floods

Supporting the flux

The soil is our greatest support for fluctuating rainfall. When the soil acts as a sponge, it can absorb heavy rains, making water available during drought. Increasing the organic matter in the soil is an essential step for creating sponge-like conditions. This can be achieved by adding finished compost, composting in place and mulching areas of bare soil throughout the growing season. Increasing the organic matter of 1 acre of soil by just 1%, allows the soil to hold an additional 16,500 gallons of water. The addition of organic matter to the soil is your best tool for addressing rainfall inconsistency with our changing climate. (https://www.canr.msu.edu/news/compost_increases_the_water_holding_capacity_of_droughty_soils). 

When it rains, aim to get as much water into the soil as possible. Direct the water to permeable surfaces instead of the sewer. Mulch your walkways, utilize permeable paving stones and, of course, gardens and lawns are excellent surfaces for the water to infiltrate the soil. The greater the water holding capacity of the soil, the greater the volume of water that will be absorbed into the soil instead of running off into the sewer. The rate the rainwater is falling can also impact absorption. Heavy rain may not have time to seep into the ground, resulting in runoff. Water gushing from a downspout may pool below the downspout or spill over into the sewer instead of seeping into the ground. Directing this water toward gardens or any areas with plant material can avoid runoff. 

Holding water in the soil

Now that the water is in the soil, we need to keep it there until plants need it. Every living thing in the soil including microorganisms, plant roots and soil particles, participate in holding water through various methods. Organic matter introduces microorganisms to the soil while providing food for them to multiply. Sufficient water also encourages aerobic conditions for beneficial organisms to thrive instead of anaerobic conditions. Decomposing organic matter creates sticky substances that help to improve soil structure by binding soil particles into larger aggregates which in turn create larger pore spaces. The binding together of clay, sand and silt particles into larger aggregates increases their capacity to absorb and store water. In addition to improved water holding capacity, this improved soil structure decreases soil compaction, increases air space availability and encourages water movement through the soil.  All this influences the biological activity of microbes by providing the aerobic conditions required for beneficial organisms to thrive and facilitates proper drainage to discourage waterlogged conditions. 

Mulch, mulch, mulch. Wherever and whenever possible, keep the soil covered. Bare soil allows the water to evaporate whereas mulch protects it from the sun, keeping the ground cool and moist. Not only will mulch prevent the water from evaporating, it will also reduce the plant’s need for water while slowly feeding the soil and increasing the organic matter. 

You won’t see all the benefits of increased soil organic matter overnight, but regularly implementing soil health practices will allow you to see a difference over a matter of a few seasons. Before you know it, your garden will be thriving during droughts and holding water during heavy rainfalls. 

Harvesting the rain

When rain falls, especially in huge volumes, rain barrels are an excellent way to store the rainwater. In heavy rain (10 mm or more), there could be upwards of 750 L of rain running off a house (based on a roof of roughly 80 sq m). Directing this to a rain barrel (or two) instead of the street reduces the demand on the municipal stormwater infrastructure. Stormwater systems in older neighbourhoods may not be designed for the heavy rainfall we see today and when they overflow, flooding occurs.  Keeping larger volumes of rainwater out of the sewer can help your neighbourhood avoid a flood. Rain barrels can also act to slow down the catchment from a roof so it isn’t damaging to the soil. If your barrel is overflowing, consider connecting a hose and opening the valve so rainwater can be directed to where it is most beneficial, such as a plant with high water needs or a rain garden. A rain barrel full of water also means that you’ll have ample water for watering plants (indoors and outdoors) during the next drought - 750 L of water is a lot of days of watering during drier periods!  If you’re interested in learning more about harvesting rainwater, check out our “Rainwater Harvesting and Management” course. You will learn everything from calculating runoff to the appropriately sized system.

Rain gardens

Rain gardens are another way of managing heavy rains. A rain garden is designed to accommodate the heavy influx of rain and to slowly release the water when the soil can absorb it. Rain gardens are a wonderful feature to add to your landscape. On the surface, they can be a beautiful collection of native plants. Below the design works to absorb and release water to prevent flooding and retain the water in the landscape.

Water-wise planting

No water wise gardening plan is complete without consideration given to wise plant choices. Including native plant and drought tolerant species in your garden can both support wildlife friendly habitat for pollinators while addressing water availability challenges. Plants like native wildflowers, native shrubs and herbs are often more resistant to pests and disease while thriving on less water during fluctuating rainfall that is associated with climate change.

In the vegetable garden it may be possible to choose varieties that are more resilient to drought while incorporating cover crops, mulch, drip systems and no till methods to help minimize water loss. Kale, Swiss chard, winter squash, root vegetables such as carrots and sweet potatoes, beans, peppers and radishes will better tolerate  drought conditions. 

Regardless of which water-wise techniques you plan to implement for the next gardening season, be sure to add plenty of organic matter to your soil. Your plants will thank you.

Written by Julia Dupuis