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Watering a houseplant - how hard can it be? Pour a certain amount of water into the plant's soil once a week to ensure quality growth - simple. However, many people unknowingly hydrate their plant using incorrect methods; thus leaving its growth and roots feeling a little uninspired. The amount, frequency, humidity, temperature, and the practice of irrigation are all factors of how well your plant will thrive. Hopefully, at the end of this post, you'll learn the do's and don't's of watering houseplants.
This is the most obvious one. If you've read any of ukhouseplants' specific articles, you should have noticed that it rarely states "water weekly" and instead writes, "water once half of the soil dries out". Learning the weight of the pot and what it means is, in our opinion, the best way to hydrate your plant. This is because every plant, in every room, of every house, is different - so why diminish it to an artificial watering schedule? Think about it this way; if you have two Spider Plants, one in a hot conservatory and the other in a dark corner of a room. Watering both via a 'weekly rota' from its label will allow the conservatory spider plant to remain dry for too long, and the other to sit in a pool of water. The result? One will suffer from under-watering, whereas the latter will develop root rot.
Now, of course, we're not trying to scare you into creating the best watering schedule known to humanity, but what we are saying is read into your plant's requirements. Study it. Keep a date of when you water it, and how much. Then, and only then, can you create a rough idea for a personalised schedule. For those in a darker location, our rule of thumb is to let around half of the soil dry out in between waters - this is to reduce the chance of root rot that's caused by a slowed rate of water-intake via photosynthesis. One additional point to mention, which is quite essential, is not to let your plant sit in standing water, especially if the plant in question prefers the drier side to life. For plants grown in brighter locations like conservatories, keep them slightly more on the moist side. There's nothing worse for a plant than sitting for an extended period in dry soil, only for the sun and heat to add to its misery. Of course, each plant is different - so be sure to read up on ukhouseplants, to get the general gist of the specific plant you have.
The best piece of advice that we can give is to learn what the weight of the pot means. The heavier the pot, the more moisture there is in it. Although feeling the top couple of inches of soil for the moisture is excellent, we only do this to pots that can't be lifted. The smaller the pot, the better the weight can be read. If you've always used your finger to test the soil, don't change it. The more you're comfortable with a particular method, the better the plants will benefit - we're just sharing our tips with you!
There are multiple ways in which you can irrigate your plant; via the top (traditional), bottom-up (flowering plants) and via submersion (Orchids). Although there are no right or wrong answers, some methods pose a more significant threat of rot to the leaves or flowers than others. This section is all about which one is best for your specific plant.
This is the method that everyone is familiar with and one that is practised the most. Irrigating from the top is easy, self-explanatory and is most natural - but it's also the one that poses a chance of foliar-related diseases. Basal rot, southern blight, botrytis and leaf spot disease are all associated with excess moisture resting on either the cubbyholes, flowers or leaves. Although the idea of water settling on the plant parts doesn't seem too bad, lower amounts of light and little to no air circulation will quickly lead to issues that are hard to eradicate. Most plants will accept this method; however, compact foliage species (Boston Ferns), flowering plants (Campanula, African Violets) and hairy plants shouldn't be watered using this method as irreversible damage may occur when excess moisture is present.
Commonly used for flowering plants like Cyclamen or Gerbera, the bottom-up method consists of plants being sat in a saucer of water for several minutes to soak up. This method is excellent for slicing out the high chance of botrytis petal blight (a disease caused by excess water sitting in the flower's cubbyholes), as well as basal or crown rot for compact foliage plants like English Ivy. To practice, set the plant in a saucer and fill up until 20% of the pot is submerged. It should only take up to thirty minutes to thoroughly soak up, and once this has been achieved, give the plant a little shake before placing back into its decorative pot. Feeling the weight of the pot is the best way to know when to irrigate again, without the need to get your fingers dirty.
The final method is mainly used for Orchids; allowing water to remain in the stem's cubbyholes will cause southern blight and botrytis. Don't be fooled by the name; never submerge the whole plant into the water, and instead, only submerge three-quarters of the pot for a few minutes. The water will access all of the bark, without leaving excess moisture to sit its cubbyholes. After a few minutes of submersion, lightly shake the plant off and place back into its decorative pot.
Some further tips to mention are not to use cold water, and if you decide to use tap water, be sure to allow it to stand 24hrs before application to alleviate both the cold temperatures and chloride found in the water. Poor irrigation habits, for example, the use of cold water, will result in sudden flower loss, stunted growth or a stressed specimen.
Our houseplants' roots can be susceptible to the extremities of hot and cold water, so using the correct temperature (around 20℃, 68℉) is vital to avoid damaging the roots. Immediately use lukewarm rainwater; however, if you decide to use tap water, allow it to sit for around 24hrs before application to help remove the harsh chemicals and coldness.
There are three main types of water that you can use for watering - rainwater, bottled water, and tap water. This section is going to discuss all methods, as well as their pro's and cons of use.
N.B. - For explanation, we use both rainwater and tap water; however, both are acceptable if used correctly. 20℃ (68℉) is the perfect temperature for roots.
If you're clumsy with waters, there are also parts of the plant you shouldn't get wet. Its leaves (especially hairy leaves), central crown and the flowers should remain dry to reduce the chance of rot and disease.
Heavy foliage plants, like Boston Ferns or English Ivy, won't like their central leaves being wet for too long, as it'll lead to southern blight. The trapped moisture will cause anaerobic respiration, forcing the leaves to breakdown and become yellow or brown. Avoiding this problem is easy; either saturate the soil from the side or use the bottom-up method of submersion.
Furthermore, hairy plants like Begonia are largely similar. Shortly after watering, its hairs can trap excess moisture that over time, can host a wide range of different issues such as powdery mildew and leaf-spot diseases. Again, try the bottom-up method by filling a saucer of water and submerging the pot until thorough absorption.
Never saturate the foliage (via misting or watering) whist the plant is in direct sunlight, as the curvature of the droplets will act as a magnifying glass on the leaves - this is what's known as 'Leaf Scorch'.
The final plant part is the flowers; intricate, small nooks that form the flower's detailed body will easily retain moisture. Blooming plants such as Gardenia, Jasmine, and Campanula should all be watered from the bottom using this method, along with the avoidance of misting the flowers for additional humidity.
If you need further advice with your houseplants, book an advice call with ukhouseplants' friendly and expert writer today! This can be done via a video or audio call on most apps, including Facebook, FaceTime & Skype. A ten-minute call costs £5.99 (US$7), or £15.99 for thirty minutes. You can ask multiple questions, including queries on plants, pests, terrariums, repotting advice and anything in between. Please consider supporting this service to keep ukhouseplants thriving!