null

ASK MARTHA: Feeding Your Plants – A Guide to the Basics

Fertilizers demystified

Question: Hi Martha, I know my plants need water and sunshine but I'm clueless when it comes to feeding them. Tell me what I need to know!

Martha: If you find yourself baffled while standing in front of the huge array of fertilizing products found at your local garden center, you’re not alone. It can be an overwhelming shopping experience. Where do you begin to select what’s right for your plants? Read on for answers to the most common questions about plant nutrition and feeding.

WHAT ARE FERTILIZER BASICS?

Plants produce their own energy; fertilizers simply add nutrients to aid in plant growth. A soil test is the most reliable guide to selecting the right fertilizer. When shopping for fertilizers, check the three-number ratio on the label, such as 24-8-16 or 12-4-8. This describes the content by percentage of the three principal plant nutrients, nitrogen, phosphorus, and potassium (often abbreviated as NPK). Use liquid or water soluble powder fertilizers for a quick boost; granular ones break down more slowly, providing a more gradual, long-lasting release.

IS FERTILIZER THE SAME AS PLANT FOOD?

Yes, plant food and plant fertilizers are the same. Quite simply, fertilizers are used to boost the soil's nutrient content, and there are a few important terms you need to know before feeding your plants.

WHY FERTILIZE? 

Plants produce their own energy; fertilizers simply add nutrients to aid in plant growth. A soil test is the most reliable guide to selecting the right fertilizer. Plants make their own sugars, proteins, and carbohydrates. To do this, they need six key elements: carbon, hydrogen, oxygen, nitrogen, phosphorus, and potassium. Plants take the first three elements - carbon, hydrogen, and oxygen - from the air and from water. They take nitrogen, phosphorus, and potassium, known as macronutrients, from the soil; these are what must be replenished with fertilizer. 

WHAT IS NPK?

The chemical symbols N (nitrogen), P (Phosphorus) and K (Potassium) are found on fertilizer labels and represent these macronutrients. When shopping for fertilizers, check the three-number ratio on the label, such as 24-8-16 or 12-4-8 This describes the content by percentage of the three principal plant nutrients, nitrogen, phosphorus, and potassium (often abbreviated as NPK). 

  • N (Nitrogen) promotes rapid growth of green leaves.
  • P (Phosphorus) – promotes root growth, as well as flower and fruit development.
  • K (Potassium)–aids the overall health of your plants 

LIQUID OR GRANULAR?

Fertilizer can be either liquid, a fully mixed fertilizer you apply directly to plants, water soluble powder (meant to be mixed with water) such as Miracle-Gro® Performance Organics All Purpose Plant Nutrition or granular (meant to be applied directly to the soil), such as Miracle-Gro® Performance Organics All Purpose Plant Nutrition Granules. Liquid and water soluble fertilizers provide a quick boost and disperse after one or two weeks. Granules are a slow-release formula, that feed over a longer period – usually up to three months, and therefore don’t need to be applied as often. The new Miracle-Gro® Shake N Feed Extended Boost is a granular fertilizer that feeds plants for up to six months.

Always be sure to read the package label for correct application directions.  

WHAT ABOUT FEEDING MY HOUSEPLANTS IF THEY COME OUTSIDE?

It’s a treat – for you and your houseplants - to enjoy the summer weather. Wait until nighttime temperatures are at a constant 60 degrees or above before bringing houseplants outside. Provide a healthy transition by placing them in a shady area first for one or two weeks and then gradually exposing them to more sun.

While your succulents and tropicals will be very much at home, be sure to respect the appropriate light conditions each indoor plant needs. Just because it’s summer, doesn’t mean that a shade loving houseplant will thrive in full sun. Closely monitor watering and feeding. Being outside will cause plants to dry out more quickly, and they may experience a growth spurt when outside. Continue to feed them as you have been indoors, with a food intended for houseplants, such as Miracle-Gro® Water Soluble All Purpose Plant Food.


Article by Martha Stewart, as part of the Growing with Martha Stewart partnership.