Crisp, dried out leaves dangling from brown stems. The slightest touch and a cascade of once vibrant green leaves fall to the floor. The humiliation of yet another houseplant shriveling into non-existence. But why!
Houseplants completely rely on us to keep them hydrated, that much is certain. The mystery is in how to stay on top of watering when: a) plants can be very confusing b) watering needs change throughout the year c) people are busy. Let’s tackle the subject of how to water houseplants from these three perspectives.
Plants can be confusing
Indoor gardening covers a broad range of plant types - from herbs, certain veggies, classic selections such as rubber trees, succulents, orchids... the list goes on. Each has its own watering requirements which are generally summarized on plant care tags by vague clues such as “water regularly” or “water infrequently”. To further complicate matters, plants’ watering needs are significantly related to container size, container style, soil type and the location where the plant ends up growing. When ever something (like figuring out your plants watering requirements) starts to feel complicated, my suggestion is to keep it simple. And here is the most simple place to start: bring the plant home, get a basic idea of what it needs from tags, books or on-line (for example: basic requirement = water regularly + full sun; or water infrequently + part sun) and just keep an eye on things for the first week or two (tending towards dry is basically a better bet compared to soggy).
All plants benefit from being watered deeply, so on the first day or two the plant is home give it a good, deep watering. You will know the plant has been deeply watered once liquid runs through to the pot’s drainage holes, or even better, if the plant can be gently tugged out of its container to reveal the entire root system; deeply watered plants will have moist soil from top to bottom. Following this first deep watering, let your plant be - but make a point of checking on things every two or three days. Most leafy plants will give you notice for a couple of days if they are dry and needing water, first by gently wilting then seriously pouting if the need for a drink becomes urgent. So, water deeply once again. Your plant will perk up quickly and now you have a better idea of how much and how often to water. Succulent or other non-leafy plants typically can go much longer without watering, so the experiment will take longer to complete. They also tend not to wilt so much as get a little prune-like. But, you will notice these changes and, just as with the leafy plant, water deeply and make a mental note of approximately how long since last watering and how much H2O is required to achieve deep watering.
A handy tool in the “observation period” is the finger hydrometer. Finger tips are very good at sensing moisture, and so experiment a little with using your finger, inserted about 1” into the soil, just after a deep watering and just as the plant starts to show leaf-signs of needing water. The rule of thumb is: if your finger can sense moisture do not water and check back in a day or two; if your finger feels dry to the touch, go ahead and water.
If you want more detail, here are some additional rules of thumb that will help establish how frequently to water houseplants:
Glazed ceramic pots breath every little and dry out slowly (often cause houseplants to be too wet)
Plastic pots hold moisture quite well, but do allow for some air penetration so long as they have drainage holes
Clay pots breathe a lot, and therefore dry out the fastest of any popular container material
Self watering containers stay moist for a long period of time, and may generally cause houseplants to be too wet
Larger leafed plants transpire (loose water through their leaves) much more quickly than smaller leafed selections - and therefore require more water.
Watering needs change throughout the year
Once baseline has been established for your houseplants’ needs, you are off to the races. That is until winter kicks in and everything changes. Plants grow at different rates depending on the season, and environmental changes such as home heating or cooling cause the soil to dry out at a variable pace. So keep an eye on things as the seasons change. Perhaps even set up a reminder to self to do a “finger hydrometer” test every three months or so, to evaluate whether or not your watering habits are in tune with your plants needs. If more precision is desired an actual water meter can be purchased that gives a more objective answer to the quandary of, “to water or not to water, now that that is the question.” Other clues indicating watering needs have changed include leaf drop and yellowing of leaves (both situations can be associated with under and over watering - examine the soil to determine which is most likely relevant). Don’t sweat it too much; the more you grow houseplants, the more second nature your adjustments to seasonal changes in watering will become.
People are busy
Even with the best of intentions and a great handle on how often to water your houseplants, it is very common to have “life” get in the way. Between school, work, family and other activities it is easy for a longer-than-planned period of time to slip by with out quite getting to the plants (I will water you tomorrow... I promise!).
The solutions to the “life” issue are a bit more holistic. For example, if you travel often or just don’t ever have enough hours in the day, low water requirement plants such as succulents can take all the stress away. If you love plants with higher watering needs, potting them into larger containers and avoiding unforgiving materials such as terra cotta will make a big difference. Another strategy that can be a default for all gardening situations is to make your own soil; potting mixes are generally very peaty and dry out fast, where as a mix enhanced with compost and coconut coir will naturally hold water in a healthy way, and slow release it out to the roots over time.
Establishing watering schedules does not tend to be completely effective since plants’ needs change through the seasons and different plants have individual requirements. However, if a schedule fits your personalty and lifestyle, the advantage of making every Sunday (for example) watering day is that at least you can check in on the plants on a regular basis and a weekly interval is a good average.
Having plants easily visible helps too. It goes with out saying that plants are usually in sight, but it is also common to tuck plants up on top of cabinets or shelves, or hang them from ceiling hooks. The small barrier of having to go out of your way to check the soil, or get in there with a watering can, mean putting watering off. The out of the way plants are most often the first to be neglected. Just a thought.
There are simple devices that look after slow release watering automatically. The most straightforward is the watering orb - essentially a glass or plastic globe with a hollow flute that is inserted into the soil. The globe portion is filled with water and natural soil hydraulics will take care of the rest! Water is released as soil dries out. The cool thing about these devices is that it makes over-watering nearly impossible. There are fancier systems such as gravity fed drip irrigation that can supply multiple pots - but most people are not looking to set up this level of automaton. Once again, the KISS (Keep It Simple Stupid) approach is often the best.
And of course there is an app (in fact many) for houseplant care! Everything from full on “plant doctor” type apps to those that are actually connected via wifi or bluetooth to in-pot sensors that will alert the home garden to the needs of the plants. Currently these sensor/app combos are quite pricey, but I can’t wait to see how this evolves. In the mean time, check out the various app marketplaces to see if there are any tools that seem helpful to your gardening style and needs.
In summary, watering is not a one size fits all activity (but generally error on the side of dry rather than soggy). Take some time to observe your plants, including over the course of different seasons, using a variety of senses (for sure “see” what your plants are doing and “feel” what the soil is doing) and also learn to match your lifestyle and interests with the plants that are best fits. You can grow amazing, long-lived houseplants!