by
Plant Doctor Christopher Satch
I often get this question A LOT, and I’m always disappointed in how the Big Hort Industry approaches watering for indoor growers. Many will say that you should water your plants every “x” days, but that is the WRONG way to approach watering. To water properly, you need to understand how long (in your conditions) it takes for soil to dry out. This changes with media type, pot type, season, heat, and light. My best advice for knowing when to water is to simply feel the soil/media, and water when dry, and use lukewarm water.
That’s right – the right time to water is when your plants are dry.
Kind of a dumb answer, right? But it’s actually the real way to water. Oh, and the water should be lukewarm too. The best practice is to feel the soil/media every few days a few inches deep, and water only when dry. Of course, if it’s a moisture-loving plant, you will want to water it as the media approaches dryness. Sometimes, folks don’t know what dry feels like – that’s because the sensation of cool and the sensation of wet are nearly the same sensation to our nerves. If you are not sure, feel how dusty or crispy the media is. If your finger comes out of the soil with fine dust or particulate matter attached, then it’s dry and needs water. If there’s small clumps of soil bits, and if you can squeeze water out of the soil from between your fingers, then there is still time to wait.
How much water should I give my plant?
You should give your plant enough water to saturate the soil. For most pots, that’s about 1/3 of the pot’s volume. If your pots have drainage holes, and you bring them to the sink, you can simply run water through the soil for a few minutes.
Yes, it really is that simple. Don’t listen to any site that tells you that you need “x” number of cups (or worse, tablespoons) of water for your plants. When it rains, it pours, and no matter where it rains, the ground gets saturated. Keep this in mind as you water. Now you’re probably wondering, “but if I use too much water, is that overwatering?” – NO! Overwatering is simply when your plants take too long to dry, not that you used too much water.
And you can quote me on that, as THE Plant Doctor! Anyone who tells you to water with a specific amount has no idea what they are talking about. That’s how you tell the difference between the amateurs and the experts.
What else should I know about watering?
Hardness/Chlorine
If you live in places like the GLORIOUS City of New York, where we get city water, chances are the water is soft water – meaning that it is low in solutes (dissolved materials, salts,etc). Other places, especially places with well water have hard water – water that is high in solutes. For the most part, plants prefer soft water – especially orchids, ferns, and epiphytes. If you do have water that is hard, you may want to consider some kind of distillation or purification device, or just collect rain water.
Now, I’m sure you’ve heard all kinds of nonsense about chlorine in tap water and how it’s bad for plants. The reality is, is that they don’t use enough chlorine in city water to harm humans or plants. So there’s no need to let the water sit out, or do anything special to remove chlorine.
Don’t know what kind of water you have? Each municipality publishes public data about their water, so you can look it up for yourself. Oh, and by the way, do NOT be afraid to drink your tap water, if the municipality deems it to be safe. If it is safe enough to drink, it’s probably safe enough for your plants. Plus, drinking from the tap is virtually free and cuts down on plastic bottle waste. Americans are too spoiled and need to do what’s right for the planet (and I say this as an American!).
Temperature/Light
The warmer it gets, the faster your plants will dry out. The more direct sunlight your plants get, the faster they will dry out. This is a good thing. It’s better to underwater than for your pots to take forever to dry. Increase light and heat if you want something to dry faster – for plants, that means put them in the sunniest window you have. If you have been reading my other articles, then you should be putting your plants in the sunniest window anyway.
Pots/Media influence
Terracotta and unglazed ceramic pots dry very quickly, and I have found that citrus in particular love to grow in terracotta indoors. Use terracotta if you are growing in north windows where you don’t get as much sun or heat to dry the plants. The terracotta is porous, and will help dry the plants faster.
Plastic pots trap water, so anything planted in them will dry more slowly. Use plastic for moisture loving plants, such as orchids, ferns, and bromeliads. Also consider plastic pots if your humidity is low.
Seasonality
The seasons will affect how quickly your soil/media dries out. For me in a temperate, 4-season region, I water the most in the winter and in the summer. Why? The winter air is low humidity, which increases evaporation, thus drying your plants faster, even though there’s less light. Additionally, heat from heaters will dry your plants faster as well. In the summer, the sheer power of the sun dries my plants our rather quickly. Honestly, in the spring and fall is when I water the least, because the mild weather and non-heating of my home leaves the media moister for longer.
The takeaway
You should be checking on your plants every few days, even if there’s no action needed. Remember, plants are living things, and they need to be checked on. Feel the soil, and let that guide you. You can always water when the media is dry.
Going a step further: Fertilizer
Fertilization is key for the longterm health of a plant. I recommend DynaGro always.
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