Fertilizing Container Plants

For most of its life, a container plant will depend on you to fertilize it in the growing season to ensure a good supply of flowers and strong growth.

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Before You Plant

It’s worth noting that a potting mix’s nutrient content will be washed out and used up after six weeks in the case of soilless mix, and after eight to ten weeks with the soil-based kind. Thereafter, fertilize at fixed intervals, or add a slow-release fertilizer. These small round pellets (like tiny eggs) are added to the potting mix in the spring. Lasting about a season, they absorb moisture and release it with the fertilizer.

Add Slow Release Fertilizer to Container SoilEnlarge Photo+Shrink Photo-DK - Simple Steps to Success: Containers for Patios © 2007 Dorling Kindersley Limited

When and How to Fertilize

Plants need a balanced supply of nutrients to grow, flower, and develop a strong root system, but this boost can be given only when they are actively growing. It is also crucial to follow the manufacturer’s instructions. Overfertilizing won’t produce bigger, stronger plants—in fact, a surge of excess chemicals can be incredibly damaging. If you are not using slow release pellets (or similar treatments), try a fertilizer that comes in liquid or powdered form (to be dissolved) that is applied on watering. The main foods are nitrogen (N), which promotes good top growth, phosphorous (P) for healthy roots, and potassium (K) for abundant fruit and flowers. The relative amounts are usually shown on the packet—for example, "NPK 6:4:4."

Use Powdered Fertilizer to Supply NutrientsEnlarge Photo+Shrink Photo-DK - Simple Steps to Success: Containers for Patios © 2007 Dorling Kindersley Limited

Food for Flowers and Fruit

A regular high-potash (potassium) fertilizer is essential when growing the likes of tomatoes and dahlias, and plants in hanging baskets, for a good crop of fruit and flower buds (it’s even good at ripening wood). It is usually applied from the moment the first buds appear, but don’t use it too early in the season, when it’s essential that the plant builds up a good, all-around structure with plenty of new shoot and root growth.

Marigolds Benefit from High Potash FertilizerEnlarge Photo+Shrink Photo-DK - Simple Steps to Success: Containers for Patios © 2007 Dorling Kindersley Limited
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Excerpted from Simple Steps: Containers for Patios

©Dorling Kindersley Limited 2007

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