Plant Answers  >  Proper Watering and Care of Poinsettia Plants

Proper Watering and Care of Poinsettia Plants

How often should I water the poinsettia and what is the best technique(s) to use? are seemingly simple questions --- yet the answer is sometimes confusing to people.

The simple and best answer is LIGHTLY, DAILY WITH A WEEKLY SOAK if drying has occurred.

Maintain the potting mix (soil) damp but not sopping wet. The dampness should feel cool to the touch. Lift up the pot after you have watered it. Take note of the weight of the pot with freshly watered soil. The weight will get lighter as the water is absorbed by the plant roots, but there reaches a point when it gets so light weight that is noticeable. It almost feels like a feather when it is dry. At that point, too, the soil actually has changed color from the dark (almost) black color of wet soil to a medium brown color of dry soil.

You never want the soil to get to that light weight, medium brown colored soil. That would be under-watering it and to rehydrate the root ball will require a soaking (described below). And you never want the soil to always be that heavy weight, dark (almost) black colored soil. That would be over-watering it. MOIST is best. Get in the habit of feeling the soil every day. That damp feel (I call it towel-damp) should be as uniform as possible each day.

Catch it before it starts going dry, but if you always have that cold, wet feel then the plant roots are so stressed with all that extra water surrounding them that they begin to go into a kind of shock. That may be when you start seeing lower leaves drop off from over-watering. They may or may not turn yellow before they drop off. You may even see the flowers (colorful leaves called bracts which are considered “the flowers”) and leaves drooping, looking like they are wilted.

Interestingly enough lower leaves also drop off if you let the soil get too dry. Flowers and leaves can droop when they are under-watered, too. In fact, that's when they really are wilted. What you see (yellow leaves, dropped leaves, drooping or wilting) all looks the same to the untrained eye, but the cause could be as different as too much water or too little water. Only the person doing the watering will know which it is.

Whenever you do water the plant, water it thoroughly until the water drips out of the holes at the bottom of the pot. That's what the holes are there for. Most people take the poinsettia to the kitchen sink to water it thoroughly. A simple method to water a plant with an abundance of foliage without having to lift and possibly damage the foliage, is to soak the water through the holes in the bottom of the pot by submerging the bottom one-fourth of the pot in standing water after removing the pot covering. The water will be absorbed by the potting mix (soil) and wet/soak the entire root ball. Once soaked, allow to drain for 30 minutes before reapplying the pot cover and returning it to the display location. After such a thorough soaking, watering will not be necessary for several days. REMEMBER, how often it needs water can be determined by touching the soil, color observation and how heavy the pot feels. After soaking the plants, they will be at their maximum weight and, as they dry, the plant will weigh less and less. A measured weight can be taken when the plants have the maximum weight (root balls are saturated) and drying can subsequently be objectively measured by actual reduction in weight.

However, the thorough watering probably doesn’t need to occur more than once every week or even every 10 days. Some folks never want to cart their plants to the sink; those people will have to water their plant where it is setting.

Examine the soil (potting mix) daily, and when the surface is dry to the touch, water the soil until it runs freely out the drainage hole in the container. The amount of water recommended for use in various sized containers ensures that enough water will be applied so that some will run out the drainage hole. The recommended amount of water to be applied when the potting mix (soil) is low moisture for a 4 inch diameter pot is 6 fluid ounces (175 ml); for a 5 inch diameter pot is 9 fluid ounces (275 ml); for a 6 inch diameter pot is 12 fluid ounces (350 ml); for a 7 inch diameter pot is 16 fluid ounces (475 ml); and for an 8 inch diameter pot is 20 fluid ounces (600 ml). Filtered water is preferred.

If a saucer or pot cover is used, discard the water that collects in it after a 30 minute drainage period. Do not leave the plant standing in water unless the plants are not going to be watered for three or more days. If a long period is expected between watering’s such as over holiday closures, use this technique with a saucer or pot cover in place. Applying water from the top (surface), soak the water through the holes in the bottom of the pot until the bottom one-fourth of the pot is standing in water. The water will be gradually absorbed by the potting mix (soil) and wet/soak the entire root ball for several days. This technique is to be used ONLY when long durations are necessary between watering’s.

A wilted plant may drop its leaves prematurely, so check the soil frequently. Plants exposed to high light and low humidity require more frequent watering. If wilting does occur, immediately water with the recommended amount and 5 minutes later water again.

Anyone who gingerly tries to water the plant with the pot sitting in its tray or dish on the living room end table will know that it is almost impossible to give the plant a thorough watering when you are more worried about spilling onto the furniture or getting the water into the pot evenly. One easy way to water the potting mix in which the plants are growing without flooding the living room is to use ice cubes when applying moisture, i.e., put 4 ice cubes (64 ml or 2 fluid ounces of water) per day per small quart-size or 6-inch pot; put eight ice cubes (128 ml or 4 fluid ounces of water) per day per medium 8-inch pot; put twelve ice cubes (192 ml or 7 fluid ounces of water) per day per larger, 10-inch pots. Ice cube size varies; the recommendations given are for ice cubes for which 20 melted cubes will produce 320 ml or 11 fluid ounces of water as measured by a standard measuring cup used for cooking.

Now how often should you water? REMEMBER, how often it needs water can be determined by touching the soil, color observation and how heavy the pot feels. Not too wet, not too dry, just right in-between.

Revised and enhanced from an article by Charlie Mazza , Senior Extension Associate, Cornell Cooperative Extension

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