Learning how to water orchids correctly is kind of tricky because orchids are pretty resilient and will put up with improper watering fora while before showing signs that something is wrong. Sometimes overwatering can be obvious and you’ll see mushy rotten roots at the bottom of the pot and a sour smell coming from the bark or moss but just as often the only sign that an otherwise healthy orchid isn’t receiving enough water is that it fails to rebloom and by that time you’ve already wasted a yearor more of caring for a flowerless orchid.
Part of understanding how to water orchids correctly is understanding how they grow in the wild. Many tropical orchids like Phalaenopsis, Vandas and Cattleyas are epiphytic which means they grow on trees rather than in soil. This habit of growing up in the air means they often get drenched in rain showers but with their roots dangling in the air they are able to dry out fully in between storms.
These orchids possess specially evolved roots perfect for life in the air. There roots are made up of a silvery-green spongy protective coating called velamen which swells with water and nutrients when wet and directs it to the middle ring of the root called the cortex. From the cortex the water enters the central part of the root called the pith where it is transported to the rest of the plant. The pith looks like a wiry white cord which you will see it if you accidentally snap the velamen of a root while repotting your orchid.
As the water moves from the velamen to the cortex the velamen will draw in air which seals the root and prevents the water from returning to the atmosphere so the orchid can go through dry periods without drying out. This process really highlights something important about orchids and their roots: they arebuilt to suck in lots of water and then dry out.Don’t let them sit in water for days because the velamen will eventually suffocate and rot. When you do water them, give them a serious drenching that lasts at least 30 seconds because the velamen needs time to suck water up for the pith.
When watering just a few orchids it’s pretty easy to stick them under a running tap for 30 seconds, drenching the potting medium letting the water freely flow out the bottom. This method also lets you get a feel for when the plant is dry and light and needing water and when it’s wet and heavy and not needing water.
Watering a larger orchid collection can take more time and personally I like to water several plants at once by soaking in a tepid sink for 15 minutes. If you keep track of how many gallons of water it takes to fill the sink up to the perfect plant soaking level you can easily add the correct amount of orchid fertilizer to the soaking water. Watering in the sink also means you can spray the plants with a foliar fertilizer while containing the mess in the sink.
Adding ice cubes to the top of orchid bark is a commonly suggested technique because it allow the ice to slowly melt and water the orchid. I haven’t had a lot of luck with this method and personally find it hard to believe that tropical houseplants would relish ice melt but if this technique works for you, adding some orchid fertilizer to the ice cube water prior to freezing would allow you to water and fertilize at the same time.
Typically orchids need to be watered once a week in the winter and twice a week in the summer. You can test the potting medium of the plant with your finger if your unsure. Slightly damp soil could use a watering, soggy needs a chance to dry out. Bone dry means you let it go too long. As you get into a watering rhythm notice the weight of the plant pot when it’s dry versus when it’s recently watered. Over time you’ll be able to tell by feel whether a plant needs water or not.
Watering Blooming Plants
Pay special attention to the watering frequency of flowering orchids. If blooming orchids are allowed to dry out to much they will respond to the drought crisis by dropping their flowers and drastically shortening the overall flowering time.
While it’s perfectly fine to get orchid leaves wet (after all, many of them evolved in rainforests!) Care should be taken that water doesn’t stay sitting in the crown of the plant where the leaves join. Water left here can lead to crown rot which will damage the plant and endanger future flowering events.
Getting to Know Your Plants
Getting into a good watering routine with orchids takes practice but watering times will provide you valuable insight into the health of your plant and give you first glimpses of brand new growths and upcoming flowering spikes.