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Cass County Extension

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Feeding   Houseplants

The correct plant food applied properly can mean the difference between your plants merely surviving and thriving. Before fertilizing, remember that more house plants suffer from an excess amount of plant food than from a lack of it. When the lower leaves of your plants yellow and fall off as new leaves are being produced, plant food may be needed. Other symptoms of a lack of fertilizer may include pale foliage, few flowers and small new leaves.

The easiest way to apply plant food is in the liquid form. Make sure to read the label carefully and follow directions. Fertilizers are sold under a variety of trade names and the formulas and instructions for dilution are different. Do not assume that if a recommended amount is good, twice that amount is better. You may damage or kill your plants. Never apply fertilizer (in either dry or liquid form) to a dry soil, as root injury may result. When applying liquid plant food, use enough of the solution to wet the soil mass. Slow release dry fertilizer mixed in the potting soil or applied to the soil surface is satisfactory. They provide a steady flow of nutrients for an extended time.

A newly purchased plant should not need fertilizer for the first three months in your home. Most plants benefit from regular feeding during active growing periods such as spring, summer and fall. Feeding should be decreased during winter months when growth has decreased. Do not fertilize resting or dormant plants. Flowering plants require extra fertilizer, applied in small amounts, when buds are forming and before blooming. Slow growing plants such as cacti and bromeliads thrive with very little plant food.

Over fertilization can cause a slowdown of plant growth, stunted plants and burned or dried leaf margins or tips. If your plant wilts or suddenly collapses and the soil is moist, over fertilization of the plant may be the cause. If you discover that you have over fertilized, you can reduce injury to your plants by leaching out part of the dissolved fertilizer by 'rinsing' the soil with clear water. To do this, you must have a well-drained soil in a container with a hole in the bottom. Place the pot in a sink and water liberally three to four times at half hour intervals, allowing the water to flush out the dissolved fertilizer and other accumulated salts. Leaching (rinsing) the soil of most house plants every three months is a good practice whether over fertilization is involved or not.

Don't expect plant food to cure all your plant problems. Feeding will not help a plant that is suffering from poor drainage, insect infestation, disease or over watering.

Todd Weinmann, Extension Horticulturist & Master Gardener Coordinator
Phone: (701) 241-5707

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