Container Gardening Principles
1. Choose Healthy Plants
Healthy plants are the key to a successful container display.
Signs of poor health include:
- General Poor condition
- Avoid plants that do not look healthy on first inspection. The moss and weeds growing on the surface of the potting mix indicate that the plant has been in its pot for too long. Spots and speckles on the leaves may indicate damage from pests and diease.
- Potbound Roots
- Ensure that the roots of the plant are not packed in a tight mesh before buying it. Plants packed in a tight mesh will take longer to establish themselves in a container display. Check this by lifting the plant out of the potted container.
- Yellowing Leaves
- This is a sign that the plant is undernourished or has root problems. Once a plant has used up all the nitrogen in its potting mix, nitrogen will be carried away from the older leaves to the younger ones (causing the older ones to turn yellow).
- Leggy Stems
- If plants do not have access to sufficient light, their stems will extend in an attempt to reach a light source. This may lead to growth which the plant is unable to support because the stems will become weak, easy to break, and susceptible to fungal attack.
2. Prepare Containers Before Planting
Always check the container to make sure it is in good condition before planting, especially if it needs to withstand the harsh winter climate. If you discover any cracks or chips in terracotta, ceramic, or stone-based materials, these should be repaired with an epoxy resin to prevent the crack from worsening. Ignoring a crack may lead to frost damage. Long cracks in terracotta can be held together by copper wire that are threaded through holes drilled on both sides of the split. Alternatively, these cracks can also be patched with fiberglass matting.
Group plants in your garden that have similar watering needs together.
Clean your containers
- Keep the inside of the garden planter clean to stop pests and disease from contaminating the new potting mix.
- Use a stiff brush and plenty of water to scrub the inside of a pot to prepare it for planting. Teracotta pots can be scrubbed out with a kitchen scourer and water, while plastic pots can be washed with soapy water and a soft cloth (to not damage its interior).
Ensuring proper container drainage
For pots that do not have drainage holes (or have inadequate drainage holes) in their bases, you will need to drill them yourself:
- Turn the pot upside-down. Use an electric drill and a masonrybit to drill a series of small holes, as closely together as possible.
- For ceramic plots, use a hammer to knock on the material between the holes to make one large single hole.
- For metal pots, mark your holes using a center punch. Before you drill thin metals, ensure that you place a block of wood under the metal surface to support it. Drill the marked holes using a large steel drill bit.
- To maximize the free passage of water through the potting mix to the drainage hole, add pieces of broken pot or stone over the drainage holes.
3. Choose the Right Potting Mix
|Peat-free mix (especially bark)||
4. Reduce Container Weight
- Roll large round pots instead of picking them up.
- An inverted plastic pot can be used to fill the internal space of a larger pot. Invert a plastic pot and cut V-shaped notches in the rim with pruners (to allow for drainage). Add a layer of gravel or lightweight beads around the inverted pot. Fill the container with potting mix, while ensuring that there is at least 12" from the rim to the plastic pot to allow for plant growth.
- Lightweight cermaic beads and styrofoam chunks can both help to bulk up the interior of the pot without adding weight to it.
- Invest in container stands on wheels.
- Get a hand-truck to transport heavy containers. Alternatively, you can always slide a sheet of heavy-duty polythene or carpet under the pot and then drag the sheet along the ground (with the pot).
5. How To Plant
- Create a design and plan. Keep the plants in their original pots and arrange them on the surface of the potting mix to get a visual ideal of how everything will look.
- Water all plants before adding them to the display.
- Keep the soil structure aerated and do not ever-firm the potting mix around the plants.
- Work from the middle of the garden container – establish your central feature plant first, then move outwards. Plant your tallest growers first, then systematically move down to your shortest.
- Position the small plants by tilting the plants on their side, so that the best foliage faces outwards.
- After planting, add extra potting mix until the container is filled to 1" below the rim.
- Reposition the plants if necessary.
- Water the display thoroughly.