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Dry And Liquid Fertilizers

When to use which

Because container plants are watered more frequently than garden plants, and the water leaches away the fertilizers, container plants need to be fed on a regular basis throughout the growing season.

 

A good rule of thumb for most plants, is to mix a balanced dry fertilizer (e.g., 10-10-10) into the soil under new plants when you put them into the container, and use liquid fertilizer for any subsequent fertilizing.

Most liquid or water-soluble fertilizers are from chemical sources, but some organic types are made from fish by-products and seaweed. Liquid fertilizers dissolve quickly in warm water and are used for foliar feeding and drenching the soil around the plants.

A good strategy for fertilizing is to buy a 20-20-20 combination (20% nitrogen, 20% phosphorus, 20% potassium) and use it at half strength (10-10-10) during the early part of the season when the plant is growing roots, leaves, and stems. At mid-season, you can switch to a 15-30-15 or even to a 5-10-10, with more phosphorous and less nitrogen to encourage flower and fruit production.

Much depends on the type of plants being grown, and the needs of each particular plant. A good full-service nursery or your nearby botanical garden employees can advise you on what's best for your particular needs.