Proper watering is crucial for a healthy poinsettia that lasts. And it’s easier than you think! In this article, we give you tips on how to make watering a breeze.
The poinsettia (bot. Euphorbia pulcherrima), also known as the Christmas star, is rightly a popular houseplant that will brighten up any interior in autumn, winter and at Christmastime – in short, during the darker months of the year. To ensure it keeps its colourful bracts for as long as possible, correct watering is essential. In fact, a poor irrigation regime is one of the most common reasons for yellow and dropping leaves. In this guide, you’ll learn everything you need to know to give your poinsettia the right amount of water and enjoy a healthy plant for longer.
Firstly, it is worth looking at this plant’s origins and natural habitat: Originally from the tropical regions of Central and South America, the poinsettia is used to warm, rather dry conditions.
In a nutshell: 5 tips for watering correctly
- Only water your poinsettia when the soil is dry to the touch, to a depth of 2-3cm.
- If possible, use soft water at room temperature.
- The amount for a normal-sized poinsettia in a 13cm pot is around 100ml or a champagne glassful.
- The ideal amount for a mini poinsettia in a 6cm pot is between half and a full shot glass of water.
- Remove any excess water from the drip tray or pot after 15 minutes to prevent waterlogging.
Want to know more? Read on to find out more details and background information.
How much water does a poinsettia need?
Poinsettias don’t need much water. How much depends on various factors, including the size of the plant and pot and environmental conditions. If in doubt, water less rather than more and be extra careful with plants in peat-free compost. These store less water than those that contain peat.
Recommended amounts of water for different pot sizes:
- Mini poinsettias (e.g. 6 cm pot): 10-20ml, equivalent to between half and a full shot glass.
- Standard poinsettias (e.g. 13 cm pot): 100 ml, the equivalent of a champagne glass.
- Larger poinsettias: Between 10 and 20 per cent of the pot volume.
Notes on water quality
Poinsettias prefer soft water, which should be brought to room temperature before watering. A little lime won’t do any harm, but if your tap water is very hard, you can either filter or boil it. When boiling, the limescale is left behind in the kettle. Alternatively, use rainwater brought to room temperature before watering.
How do you water a poinsettia?
There are various methods of watering poinsettias, each with advantages and disadvantages. We recommend watering from below.
Watering from below
When watering from below, pour room temperature water into the drip tray or planter every day or every two to three days, depending on the plant’s location and size. This allows your poinsettia to soak up the amount it needs. If you notice the water level hasn’t changed for 15 minutes, drain the excess water away.
With this method, the soil surface often still looks dry after watering, but when you lift the pot, you’ll notice from its weight that there is enough moisture in the soil.
Watering from below is gentle on the sensitive roots. It minimises the risk of waterlogging as excess fluid can simply be poured off. Capillary action is why watering from below works.
Watering from above
Watering from above is probably the most common method for irrigating houseplants. You water straight onto the compost in the pot (leaving the lower leaves dry). This method has its advantages, but also some risks.
Advantages:
• Simple: Watering from above is easy and quick. It’s also practical if the poinsettia is in a place that’s difficult to access or if it’s in an arrangement.
• Control over the amount of water: You can easily monitor the amount of water.
Risks:
• Danger of waterlogging: If you water too much, the liquid may collect in the planter or drip tray. If it’s left there, waterlogging occurs, which suffocates the roots and leads to root rot.
• Uneven moisture: When watering from above, you may not add enough and the soil may be moist at the top but still dry at the bottom. This can lead to the roots not being evenly hydrated.
Tips for watering from above:
• Water slowly: Pour the liquid slowly and evenly so it has the opportunity to penetrate the soil and distribute itself evenly.
• Watering can with a narrow spout: Use a watering can with a narrow spout to dose the water more effectively and avoid stirring up the compost too much.
• Beware of waterlogging: Don’t leave any excess fluid in the planter or drip tray for longer than 15 minutes to prevent waterlogging. You should add a drainage layer to planted arrangements.
Immersion method for poinsettias
Another method is by immersion, which should be carried out about once a week, depending on the plant size, ambient temperature and location. It’s often the only way to rehydrate severely dried-out compost.
Here’s how it’s done:
• Take the poinsettia out of its planter and place it in a deep bowl or bucket of room temperature water. Make sure the root ball is just below the surface of the water. As the water flows into the compost, it will bubble.
• Wait until virtually no more bubbles rise. Only then will the soil be sufficiently saturated.
• Allow the poinsettia to drain well.
• Put it back in its planter.
• Empty any residual water from the tray or planter after 15 minutes to prevent waterlogging.
How often should I water?
There’s no set rule for how often a poinsettia needs watering – it may be necessary daily or just once a week, depending on the conditions. Observe your plant and adjust the frequency to its individual needs. The warmer it is in the room, the faster the soil will dry out. More frequent watering may also be necessary with peat-free compost. You might have to water more often in hot rooms during the winter months. Small pots dry out more quickly than larger ones due to the smaller volume of soil. They may need water every day. Simply giving more water less often isn’t an option, as poinsettias can’t tolerate waterlogging.
Tips for determining the right watering frequency:
- Finger test: Insert your finger about 2cm into the compost. If it feels warm and dry, it’s time to water. If it still feels moist, wait a little longer.
- Weight check: Lift the pot. If it feels lighter than usual, your poinsettia needs water. A heavy pot indicates there’s still enough moisture (this check doesn’t work as well with peat-free compost).
- Colour of the soil: Check the colour of the compost in the pot. It will become lighter when it’s time to water (this check doesn’t work as well with peat-free compost).
Watering poinsettias during the dormant phase
After flowering, poinsettias enter a dormant phase. During this period, they need less water and a slightly cooler environment (around 15°C). As a rule, a little water once a week is enough to keep them alive. Make sure the compost doesn’t dry out completely, but also avoid waterlogging. When the plants emerge from dormancy and sprout new leaves, you can gradually increase the frequency of watering.
Watering poinsettias correctly: the most frequently asked questions
Here are the most frequently asked questions about the right way to water poinsettias – and the answers.
How much water does a poinsettia need?
How much water a poinsettia needs depends on the plant and pot size and environmental conditions. As a general rule, water less rather than more to avoid waterlogging. Use the recommended amounts of water for different pot sizes as a guide and adjust them as required.
What is waterlogging and why is it harmful?
Waterlogging occurs when excess liquid is left in the pot and the plant’s roots are permanently standing in water or waterlogged compost. This can suffocate the roots as they have no access to oxygen, leading to root rot and the death of the plant. Poinsettias react to a build-up of water in the pot with yellow leaves.
How do I avoid waterlogging?
- Remove any excess liquid from the tray or pot about 15 minutes after watering.
- Reduce the amount of watering if there is always water left over.
- Ensure planted containers have a functioning drainage system and, if possible, add a drainage layer.
Why is my poinsettia dropping its leaves?
Leaf shedding can have various causes, but is often due to incorrect watering. Too little water leads to dry, limp leaves, while too much causes yellow leaves and root rot. Be sure to use the right amount of water and the correct watering frequency to avoid these problems.
What can I do about drooping, green poinsettia leaves?
If a poinsettia’s leaves are drooping, the compost is too dry. The roots can’t get enough water to send to the leaves. First individual plant cells die, then the whole poinsettia. If the compost dries out so much that it comes away from the edge of the pot, it’s unlikely you can save the plant by watering it. Tip: Take extra care with mini poinsettias. Because the pot volume is small, the compost dries out very quickly. This applies to all mini plants.
➡️ Find more tips on how to care for mini poinsettias in the article Mini poinsettias: gift ideas and care tips.
What should I do if my poinsettia's leaves are limp and yellow?
Poinsettias get floppy, YELLOW leaves from too much water, not too little. They are the most obvious symptom of the notorious waterlogging. Under no circumstances give the poinsettia any more water. Check whether there’s any liquid in the tray or pot. If so, pour it away and only water again when the compost has dried out. If you’re lucky, your poinsettia will recover.
Should I water every day?
That depends. In the ideal location, daily watering isn’t usually necessary and can even be harmful. Poinsettias should only be watered when the top layer of soil is dry. In many cases, watering every few days or once a week is enough, depending on the environmental conditions. The smaller the pot, the more often you need to water.
How do I water a mini poinsettia?
Mini poinsettias need to be watered more frequently than their larger relatives, but water them sparingly; 10-20 ml (half to full shot glass) is enough.
Make sure the compost doesn’t dry out, but also avoid waterlogging.
Can I save my poinsettia?
If your poinsettia has been badly affected by inappropriate watering, there’s no guarantee it will recover. However, there are two measures you can try:
• If there’s not enough water: Water the plant thoroughly or immerse it in room temperature water until there are no more air bubbles. Then allow the plant to drain well.
• In case of waterlogging: Remove the plant from the pot and look at the roots. Cut off any rotten, black roots and replant the poinsettia in fresh, free-draining compost. Water sparingly and make sure any excess liquid can always drain away easily.
What is capillary action?
An everyday example: If you hold the corner of a paper towel in a puddle of water, the liquid is slowly absorbed into the rest of the paper towel. This is due to capillary action. The fine pores in the material act like small tubes that transport the water upwards. The water sticks to the fibres in the paper towel. This is called adhesion. At the same time, the water molecules also stick to each other. As soon as some molecules climb upwards, the others follow. This is cohesion. The water climbs up through the tiny fibres in the cloth, just as it climbs from the bottom to the top of your poinsettia through adhesion and cohesion in the compost.
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