Lesson 3: Watering, Humidity and Fertilizing
Watering practices, humidity, and fertilizing routines affect the quality of your plant's growth. You need to learn the preferences of your houseplants and seek to provide optimal conditions for their growth.
Introduction to Water, Humidity, pH, and Fertilizers
Goals: Student will learn to check water content in potting media, air humidity, and the pH of both potting media and water.
Tools: humidity meter, water meter (if desired), pH meter, bamboo skewers (used for kabobs)
Water, humidity and pH of potting media and/or water used for watering all have an effect on the growth of your plant. Your plant will have a preference for the amount of water in its potting media. Plants also have differing needs for humidity in the atmosphere. Some plants wan5t a humid atmosphere (humidity = amount of water held in air at varying temperatures. Warm air holds more humidity than cold air.) Most fern species prefer high humidity while most cactus and succulents prefer little or no humidity. The pH of water and potting media will be discussed later in this lesson.
Water is essential for all plants including succulents. The amount of water used by a plant will vary widely. Some plants want to grow in nearly 100% water (aquarium plants) while others want minimal water (cactus and succulents). If you show an unidentified plant to a professional grower and ask how often you should water it, you will usually receive the answer of "it all depends". Although this sounds like an evasive answer, the truth is you must know the proper identification of a plant in order to know where it grows naturally and what the average humidity is in its natural home.
Recognizing watering problems can be difficult. Take special note that plants growing under lights receive optimal quantities of light each day. This means the plant doesn't change its watering needs from season to season. It also means you have total control over the quantity and quality of water received by your plant. Here are some general signs of under-watering and over-watering.
Signs of under-watering
If the plant is wilted, feel the soil. Most wilted plants will have bone-dry soil. Check your potting media. Water most plants if the media is dry to the touch. Succulent leaves or stems begin wrinkling when the plant needs additional water. You can often tell a plant needs watering just by lifting the pot. If it is lighter than usual, water the plant.
Signs of over-watering
Look at your potting media. Is it soggy? Does it have a rotten smell? These are signs of too wet potting media. Do the roots look mushy? This means the roots aren't getting adequate oxygen because the pores in the potting media are filled with water. If this happens, take the plant out of the pot (complete with potting media) and set it on newspaper to absorb excess water. Then trim the roots back to those that still appear healthy and repot. If the plant stems look mushy or have a rotting smell, the plant is suffering either from over-watering or from a disease. Unpot the plant and trim back to a healthy portion. Use the healthy portion to restart the plant following instructions given in the lesson on purchasing and transplanting houseplants.
