Healthy soil is the foundation for your lawn and garden. Good soil structure is created by billions of soil organisms to allow air, water and plant roots in the soil. Soil organisms feed on organic matter such as mulch and compost and recycle nutrients back into the soil. By starting with healthy soil, you will save time, frustration, money and water in the long run. A healthy soil will hold more nutrients and water resulting in healthier plants.

Know Your Soil

It is important to know the type of soil you have: sandy, organic matter, loam, clay or mineral soil. Sandy soil will drain quickly compared to a clay or mineral soil that retains more water. Learn how to evaluate your soil quality.

Maintain a neutral soil pH (6.5-7.5). A pH test from a garden centre can help you understand the acidity of your soil and improve growing conditions for your plants. If your soil is acidic, amend your soil with organic matter or lime to obtain a neutral pH. Many vegetables prefer a neutral, however some like it slightly more acidic.

If you are an urban gardener, test your soil for heavy metals and contaminants. You may do this for free through the Healing City Soils program.


Look for areas of compacted soil. Aerate your soil before planting. Compacted soil does not have enough space for air and water to move easily to plant roots and can harm beneficial soil organisms.

Prevent soil compaction by walking on garden beds as little as possible and avoid heavy equipment on the soil.


Add compost. Compost helps keep your soil loose, fertile, retain moisture and allows drainage. Amend compost to the top 15 – 30 cm of soil over the entire planting bed. For new garden beds amend soil with 5 – 8 cm of compost. For existing garden beds, amend your soil with 2.5 cm of compost every year. More compost should be added to sandy soil, compared to clay soils to help retain more moisture.

When choosing compost, look for:

  • Earthy smell
  • Dark brown or black colour
  • Fibrous texture
  • No weed sprouts


Add mulch. Mulch is any material added onto the soil surface and is often organic including: leaves, compost, grass clippings, straw, wood chips and coarse bark. Choose a mulch appropriate for your plants as some mulch an increase the acidity of the soil.

Mulch a 5-10cm protective layer around plants in early summer. Mulch reduces the number of weeds, conserves soil moisture, moderates soil temperatures, reduces soil erosion and adds beneficial nutrients back into the soil. Keep mulch at least an inch (2.5cm) away from plant stems to prevent rot and pest damage.

Fall mulch can also be added to reduce soil erosion and maintain warmer soil temperatures. To smother aggressive perennial weeds, add a brown cardboard or several newspaper layers, water and mulch on top. This will block light from reaching weeds and should help reduce numbers.

More information about mulch.

Water Wisely

Most plants only need an inch (2.5cm) of water per week. Overwatering encourages plant disease, soil runoff, shallow root development and excludes air from roots. Learn more water wise garden tips.

Skip the Fertilizer

By using the above techniques, your plants should not require the addition of fertilizer. If you do choose to fertilize, use natural organic and slow-release fertilizers and fertilize sparingly. More fertilizer does not mean better as it can change the pH of your soil and runoff to pollute local streams and waterways. Mulch can often provide the necessary nutrients for plants.