Welcome to Your Orchid Adventure Lesson 4- Water Requirements

Assuming your orchid is getting the correct amount of sunlight for its genus, the second most important thing to consider is how much water it needs. This can vary between the genera and sometimes between the seasons of the year. It’s important to understand your orchid’s growth cycle to determine how much water it needs throughout the year.

Plants use the process of cellular respiration to break down stored carbohydrates for use in plant maintenance and blooming. A key component of cellular respiration is water. So, if your orchid is actively making more plant material or blooms, it will use more water. When the plant is resting or in a dormant phase, it will use less water. If you understand when your orchid needs less water, you can avoid overwatering. The AOS Care & Culture sheets that we talked about last month can help you with this.

The type of media you use will also affect how frequently you need to water your orchid. Bark and sphagnum moss make orchid media more water-retentive. For example, imagine you have two Phalaenopsis orchids. One is planted in a medium with bark and moss, one is not. These two plants will dry out at different rates. The one without the bark and moss will need to be watered more frequently. For this reason, it’s always a good idea to have plants in the same genus planted in the same type of media, as it makes watering easier.

When and how you water can be as important as how often you water. Overwatering occurs when you consistently provide more water than the plant can take in. This leaves water lying around the root system, which leads to decay and rotting. Generally, it’s best to water earlier in the day. The plant will photosynthesize during the day and take up the water for that process. There are two main ways you can water. First, you can pour water or run water from a spigot over the media and allow it to drain through, wait a few minutes, and repeat the process. Alternatively, fill a pitcher with water and an empty bucket. Hold the plant over the bucket, then water thoroughly, allowing the water to drain into the bucket. The key with both methods is allowing the pot to drain before putting it back in its saucer or decorative container. You never want to water an orchid while it’s in a decorative container that does not have a drain hole. This allows water to sit at the bottom of the container and rot the roots.

The type of water used is also a consideration. Most orchid genera will do fine with household tap water, rainwater, or bottled spring water. It’s not necessary to buy reverse osmosis (R/O) water. Household tap water cannot be used directly from the spigot if there is a “salt-based” water softener because the sodium these systems add to the water in removing hardness rapidly becomes toxic.

A final note about watering is that it is always best to water with tepid water – not too hot, not too cold. I would also be remiss if I didn’t address the “ice cube” watering technique. This is an amazing marketing idea that was intended to prevent overwatering. There are two main problems with this technique. First, Phalaenopsis orchids are from subtropical areas where they would never come in contact with ice in their native environments. The constant cold from the ice stresses the plant. Second, the salts dissolved in the ice slowly build up in the potting mix because there’s nothing flushing the potting medium.