The ideal time to plant annuals is done when the risk of frost is past.
- Whatever the types of containers, the right plant at the right place is the key to success.
- Group annuals in the same container that have similar cultural requirements.Choose annuals adapted to the environmental conditions that prevail in locations you wish to place your pots:
- number of hours of sunshine
- intensity of the sun (noon, 10h00-14h00)
- shade and wind
- For sunny and windy locations such as balconies, choose resistant plants such as petunias and geraniums.
- If the location is exposed to the north and in the shade, choose plants adapted to shade and humidity such as impatiens, fuchsias and begonias.
By selecting appropriate plants, you ensure to have plants adapted to their environment, therefore less susceptible to insects and diseases.
There are many containers on the market to choose from: pots, balcony planters, garden urns, hanging baskets. There are some for every taste and budget, made from different materials: plastic, terracotta, stone, cement, etc.
Good to know:
- In sunny area - select light coloured containers to avoid overheating. Darker containers absorb more heat which causes the soil to dry faster and then plants require more water.
- Choose containers large and deep enough to provide a better reserve of water to plants. The smaller the container the more it will require water.
- Patio planter - more than 30 cm of diameter
- Balcony planter -more than 25 cm wide for a.
- Make sure selected containers have one or several drainage holes so that the water can be evacuated, if not, holes have to be made. (1,5 cm of diameter at every 25-30 cm)
- If you are to leave your containers outside during winter, make sure the materials is resistant to frost (ex: stone, plastic, wood, etc.) and others not (ex: unvarnished terracotta, etc.).
The soil must be able to retain water and nutrients. Therefore, it is important to use a very rich, well aerated and quality soil. You can make your own soil from peat moss, compost, perlite, etc. Some commercial potting soils were specially developed to ensure growth and flowering of annuals in containers.
Select a mix specifically for plants in containers with:
- Good water retention;
- Starter fertilizer;
- Crystals (polymers). These crystals allow absorbing and retaining water which is released when the soil becomes dry.
Planting annuals step by step
1. Preparing the soil
- Mix the selected soil in a large container or a wheelbarrow;¸
- Humidify the soil, without drenching, before putting in the containers;
- Add a fertilizer of natural origin (ex: seaweed meal or feather meal) or a slow-release fertilizer with the formulation near 4-8-4. Always follow the dose recommended by the manufacturer.
2. Filling the containers
- Check for the presence of drainage holes at the bottom of the pot;
- Fill the container up to two thirds with the moistened soil;
- Gently knock the pot on the ground once or twice to firm the potting soil;
- Pack gently with your hands the soil within the perimeter walls. Avoid compaction in the center of the container as to not inhibit root formation;
- Fill so that the surface soil is 2 to 3 cm from the edge of the container;
- After planting or watering, readjust the level of the soil if necessary.
3. Preparing plants
- Water plants at least one hour before;
- Remove wilted flowers, dead stems and yellow leaves to promote root growth;
- Prune in half all the wilted etiolated stems, even if they have flowers. This procedure will promote the development of new shoots increasing flowering. Pruning of the wilted etiolated stems can also be done once annuals are planted;
- Remove from the pot and if roots are coiled around the root ball, cut by practicing three or four incisions with a knife. Gently release them, taking care not to undo the root ball. This procedure will stimulate root growth and facilitate the plant’s adjustment to its new environment.
4. Planting and spacing
- Start planting at the center of the pot and finish with border plants according to the planting sketch;
- Make a hole and place the collar (where the stem meets the roots) at the same level as in its original container;
- Add the mix around the plant and lightly pack the soil without compacting it;
- Space plants adequately so that they can develop and flower. May be spaced half the distance of what is indicated on the label. A distance of 10 to 20 cm is appropriate for most annuals in containers. Some vigorous or larger-scale annuals require more space (ex.: Surfinia at 30 cm);
- Add mycorrhizas at the bottom of each hole. Mycorrhizas are beneficial fungi that promote the absorption of nutrients and water and increase plant resistance to drought.
- Once planting is done, slowly sprinkle the soil two or three times until water trickles through the drainage holes.
Always check if watering is necessary by putting one finger in the soil down to the first phalanx. If soil is moist at that distance, where roots are located, it is not necessary to water.
The ideal time to water plants is in the morning.
Before using an amendment, a pesticide or a fertilizer always read and comply with the product label. Pay special attention to instructions, precautions to be taken before, during and after using the product and storage conditions.