Care of Plants Growing in Containers

Gardening in containers is a great way to interest and color to outdoor areas and make patios, porches, steps, and walkways more inviting.  There are several things that should be done throughout the growing season to keep these containers looking good.

shade containerWatering

The frequency of watering may vary considerably from container to container. In general, containers need much more frequent watering than garden beds.  Watering frequency depends on the size and type of container, composition of the potting mix, plant species, and weather conditions. 

Plants growing in containers should be checked daily (especially in summer) to determine if they need to be watered. They often have several plants spaced closely together in potting soil that is well-drained.  If uncertain about the need to water, poke your finger into the potting mix.  Water the container when the potting mix is dry at the 1 to 2-inch depth.  Watering frequency may vary from once or twice a day (small container, hot windy weather) to once or twice a week (large container, cool weather).  

When watering plants in containers, continue to apply water until water begins to flow out the drainage holes in the bottom of the container. 

Do not allow the potting mix to dry out completely.  Potting mixes shrink and pull away from the sides of the containers when completely dry.  Dry potting mixes are difficult to moisten as water tends to flow between the potting mix and container and then out the bottom of the container (while the potting mix remains dry).  Containers that have been allowed to dry out completely should be placed in a tub of water for 20 to 30 minutes to remoisten the potting mix. 

container on deckFertilization

Plants in containers need to be fertilized on a regular basis as nutrient levels in potting mixes quickly fall due to absorption by plants and leaching during watering. 

Apply water-soluble fertilizers every 1 to 3 weeks throughout the summer.  Granular and slow-release fertilizers can be added to the soil surface (or lightly incorporated before planting) in early spring and may need a second application mid-season.  Check the product label for application rates and frequency. 

Look for complete fertilizers with a 1:2:1 ratio of nitrogen, phosphorus, and potassium to keep plants healthy and blooming well. Fertilizers that are high in nitrogen should be avoided as they cause excessive vegetative growth at the expense of flowers. 

Many commercial potting mixes contain a slow release fertilizer.  However, slow release fertilizers usually don't last the entire growing season.  When using a potting mix containing a slow release fertilizer, begin to fertilize plants when plant growth slows or the color of the foliage fades, typically about mid-season.  

group of containersOther Maintenance Chores

Remove spent flowers on annuals to improve plant appearance and encourage continuous bloom.  

Pinch back plants that get tall and leggy. Cutting back plants helps promote fresh new growth that will be more attractive and produce more flowers for the remainder of the growing season.  

Consider replacing plants that get too large. By September, containers can start to look overgrown and the abundant roots become difficult to keep well-watered.  Early fall is a great opportunity to swap out plants with cool-season annuals that tolerate a light frost and allow you to continue container gardening well into the fall.

Inspect plants on a regular basis for insects and diseases.  Control insects by handpicking.  Control diseases by removing infected leaves or entire plants.

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Last reviewed:
June 2024