Fertilizing container gardens can often be a confusing process. When should I feed my plants? What should I use? Do different plants need different food? These are all questions gardeners are constantly asking themselves. If you are a new container gardener, be sure to read the box below to become familiar with how to read a fertilizer label.
If you are planting your containers with a commercial mix, the nutrients needed for plant growth and health are incorporated into the mix. This should be good for 3-4 weeks. Because watering leaches fertilizer, how often you water should determine how often you fertilize your container plants.
If you are using your own soil mix, or if the container has been planted for a while, you may want to do a soil test to determine the pH of your soil. If your soil pH is too high or too low, your plants will not be able to access some nutrients, even if they are present in the soil. A pH Soil Tester can be purchased online or at your local garden center.
When fertilizing your container plants, it is helpful to know the requriments of your plants. Some plants require alkaline soil while others prefer an acidic soil. The only way to know what each plant prefers it by research and reading up on the plants you have decided to use. This information is often on the plant label or seed packet, but if it isn’t listed, you can check the plant name on the Internet or in your gardening books.
How to Read a Fertilizer Label
If you’ve ever shopped for fertilizer you may have become totally confused with the wide array of products available. The FDA has standard labeling rules to help you understand and compare fertilizer ingredients
Most commercial fertilizers have 3 numbers on the front label, separated by dashes. For example: 5-10-5. This is the fertilizer analysis or percentage by weight of the 3 major nutrients plants need: nitrogen, phosphorus and potassium, in that order. These are abbreviated as N-P-K.
- The first ingredient listed is Nitrogen. This encourages foliage growth, among other benefits. A 5-10-5 fertilizer would contain 5% nitrogen by weight.
- The second ingredient lists is Phosphorous. This ingredient contributes to the plants rooting system and bud setting.
- The third ingredient is Potassium. This mineral contributes to the overall health and vigor of plants.
Other ingredients are usually listed on the side of the bag. No one fertilizer is suitable for every plant, so often you will be looking for a boost of extra ingredients.
Some container gardeners prefer to fertilizing container gardens with a weak solution every other watering. If this is a method you prefer, use only 1/4 of the solution called for in a monthly application. Plants in containers need more nutrients than those planted in a garden because of the small volume of soil in the container and also the frequent watering schedule that is required. It is necessary to compensate for the smaller root area by a more frequent watering and feeding schedule.
No plant requires a large amount of fertilizer at one time, but by continuously feeding your plants on a regular schedule, you will encourage lush growth and a continuous display of color. Do remember that smaller pots and lighter soil will need to be fertilzed more frequently than larger pots filled with heavy soil, as frequent watering leaches nutrients out of the soil.
The proper way of fertilizing container gardens
Never fertilize your container gardens when the soil is dry. Fertilizer that touches dry roots may shock your plants. Be sure the soil is moist before you fertilize your container plants A plant with moist roots is at the optimum level for taking in nutrients.
It’s also good policy to fertilize your plants in the morning. As the sunlight and heat increase, plants start what is called “transpiration”, the process of releasing moisture through their leaves. As this moisture is evaporated, more moisture is absorbed by the roots, thereby carrying the fertilizer to all parts of the plant.
Timed Release Fertilizer
Many people prefer fertilizing container gardens with a timed release formula. As the plant is watered, the fertilizer is released in small amounts. This eliminates the need to remember when you last fed your plants yet satisfysthe plants need for a constant supply of nutrients. Always follow the label instructions when using any commercial garden mix or fertilizer. Over fertilizing can be as detrimental to your plants as under fertilizing.
Special “Mixing Nozzles” for your hose
You can purchase specialized nozzles for your hose that pre-mixes fertilizer for direct delivery for your plants. Miracle Grow, Rapid Grow and Hyponex along with other liquid fertilizers all produce these nozzles for use with liquid fertilizer. This is a great time saver if you have a lot of containers as you no longer have to mix fertilizer in a separate container.