How to Fertilize Container Gardens

Container gardens can benefit from the controlled environment you create for them only if you give them the nutrients they need. Fertilizer is important for all plants, but it is especially important in container gardens because they don't have access to organic nutrients found in the ground. Follow the steps below to boost your container garden's growth.

Difficulty: Moderately Easy

Instructions

1. Decide whether to use organic or inorganic fertilizer for your container garden's main nutrient source. Both types provide plants the nutrients they need, but they have different advantages and disadvantages. Inorganic fertilizers cause salt to build up over time, a problem in containers if you are growing perennials. Organic fertilizers completely break down and therefore do not leave salt residue, but are more complicated because you have to use several different types of organic fertilizers to get all the nutrients your plants need.

2. Understand what nutrients are in fertilizers. All plants need three main nutrients: nitrogen, phosphorus and potassium. These nutrients are represented on the fertilizer packaging by three numbers, separated by dashes. The higher number, the higher the nutrient content. Nitrogen is the first number, phosphorus is the second number and potassium is the third.

3. Use a somewhat balanced fertilizer. All plants need some of each nutrient. However, foliage plants need more nitrogen and blooming plants which bloom need more phosphorus. If you are growing foliage and blooming plants in the same container, stick with a balanced fertilizer. Inorganic fertilizers provide some of all three nutrients and organic fertilizers, such as blood meal, bone meal, greensand and fish emulsion, only provide one so you have to use several different types.

4. Mix in compost when planting your container garden. Compost is a good source of microorganisms which break down nutrients so your plants use them.

5. Add new compost every year if you are growing perennials. Perennials deplete the soil in their container of microorganisms in one season. Sprinkle a layer of compost on top of the container early in the Spring.

6. Feed the container garden a couple weeks after initial planting, following the directions on the fertilizer package. Continue feeding full strength until Fall when temperatures begin to cool. When temperatures cool, reduce feeding. Stop fertilizing trees and shrubs grown in containers in mid-summer as they need to begin preparing for winter dormancy.