What is potting?
Plants can be grown in containers inside or outside. This practice is known as potting. Container plants need to be repotted into larger pots as they grow. Early spring is usually the best time for most plants. Trimming the roots and refreshing the soil give most pot-bound plants a new lease on life. You can maintain a large plant this way for many, many years!
When and how?
Recognizing when it’s time to re-pot your potted plants is the first step.
Tell-tale signs include soil that dries out quickly or has become degraded; roots tightly packed within a pot or protruding from drainage holes; and water sitting on the soil surface too long after watering.
Often a plant simply looks top-heavy or as if it might burst out of its pot. The best time to repot most plants is when they’re actively growing, in the spring or summer. However, most plants can usually handle repotting whenever necessary.
To remove the plant from the pot is usually not too difficult. If a plant is root-bound, it helps to water the root ball thoroughly in advance. For plants in small to medium pots, invert the pot and support the top of the root ball with one hand. Put your other hand on the bottom of the pot and use a downward throwing motion with an abrupt stop. Many plants will slip out after one or two throws. If not, knock the edge of the pot against a sturdy surface, such as a potting bench, still holding the pot with both hands. It may take a few good whacks to release the plant; be careful not to break the pot.
A plant ready for repotting should slide out easily with the soil all in one piece. If the soil comes free of the roots, the plant may not need repotting. If it does, there will likely be a solid soil-and-root mass in the shape of the just-removed pot. Roots should be white or light-colored. Black, dark-coloured, or foul-smelling roots usually indicates signs of a serious problem, such as a fungal disease.
To prevent the plant strangling itself you need to cut through any roots growing in a circular pattern. Thick roots along the sides of the root ball should be shaved or peeled away from the outer layer. Continue to gently untangle the root ball with your fingers as if you were mussing someone’s hair. Do this along the top edge of the root ball, too.
Pot size is usually determined by the plant and its potential growth rate and the ultimate size desired for the plant. Use your own judgement of what a healthy specimen of a particular species should look like. When in doubt, go with a pot the next size up.
To keep soil from leaking out the bottom of the pot, cover its drainage hole(s) with a paper towel, coffee filter, mesh screen, or pot shard. If you use a pot shard, place it convex side up to avoid sealing the hole. Gravel and other items shouldn’t be used at the bottom of the pot since it can take up too much valuable growing space.
To repot a small plant that’s easy to lift, put a few inches of moist soil in the pot and tamp it down lightly. Place the plant in the center of the pot. The goal is to get the top of the root ball to sit about 3 cm’s below the rim of the pot.
Now, fill the space around the root ball with soil. There are two approaches to this job — “stuffing” and “filling.” Filling usually works better especially with deep pots that are hard to stuff. Whether you stuff or fill, leave some room at the top so the pot can hold enough water with each watering to thoroughly moisten the soil.
Finally, trim the plant’s foliage relative to how much the roots were pruned. In other words, if you removed a third of the roots, prune off a third of the top growth as well. Water the plant thoroughly and keep it moist, shaded, cool, and misted until it is re-established.
Keep potted plants well-watered and fed after repotting.