Potting-soil pointers for container gardens

Plants growing in containers need quick-draining, fluffy, light soil; the easiest route is to buy container potting soil, although you can also mix it yourself. Here are some pointers for getting it right.

• Packaged potting soil is readily available and is sold in bags up to 25 kilograms (55 pounds)
• There are differences in quality and price among brands, but you should buy the best you can afford
• Begin at a nursery or garden centre, and ask for the best potting soil available
• Try out a small bag
• When you find a product you like, you can buy it in larger quantities, usually at a discount

Whether you buy it or mix your own, the potting soil should be a fine-tuned mixture of peat moss, compost, and a little sand, with small amounts of puffy white perlite or flaky vermiculite added to lighten the mix and aid drainage.

Some warning signs of poor-quality potting soil are:

• a clumping, claylike consistency
• numerous wood chips or sticks
• an extremely gritty feel
• colour that is either grey or light brown rather than dark brown to black

• Many potting soil manufacturers have begun adding fertilizer to their mixes
• Potting soils that include fertilizer simplify the planting process, because you don't need to mix in fertilizer as you plant or begin feeding plants for several weeks after planting
• Potting soils without added fertilizers are still a good value though, and it's easy to sprinkle in small amounts of a balanced granular fertilizer as you fill pots with potting soil (or begin fertilizing after planting with a water-soluble formula)

• Fill a large bucket or wheelbarrow with two-thirds compost that has been screened to remove sticks, stones, and clumps
• The remaining one-third should be a combination of peat moss and either perlite or vermiculite, which are available at any garden center or nursery (wear a dust mask when mixing in these dusty ingredients)
• Stir the mixture together to combine all ingredients and you're ready to plant

• Spread a layer of pebbles or pot shards over the drain holes of a container to keep soil in while letting excess water drain out
• Add soil until the pot is about three-quarters full
• Shake or rock the pot gently to help settle the soil, and place the root balls of your plants on the soil, building it up as needed so that the base of each plant is just below the rim of the pot
• Continue filling soil in around the plants and shaking until the soil reaches 2.5 centimetres (one inch) from the pot rim; if you plan to top the soil with an ornamental mulch, fill to five centimetres (two inches) of the rim
• The soil should not "shrink" too much if you've shaken the pot and covered the drain holes properly
• Large containers should be placed in their final position before being filled, so that they won't have to be moved when heavy with soil

Garden soil and commercial topsoil intended for use in garden beds are too heavy for container gardens. By purchasing a quality container potting soil, or mixing your own, you can get enjoy the best performance from your container plants.