The manner in which you water the Day's cymbidium will depend somewhat on whether or not your plant is in an active growth phase. If so, you should apply water to your plant’s soil and, if the weather is warm, perform occasional overhead watering to allow the plant to absorb moisture through its leaves. By contrast, in winter, and when the weather is cool or wet generally, you should stick to watering the soil directly rather than including overhead watering as well. You’ll know your Day's cymbidium needs more water if its roots and leaves become thin and dry or show discoloration. Day's cymbidium receives too much water will look mushy and limp. You should grow your Day's cymbidium in a pot and ensure that the potting mix you use has fantastic drainage. During the growing season, you’ll need to water this plant multiple times per week. However, each watering should drain quickly through the growing medium to prevent any standing water. The amount of water you give will change based on the size of the pot you use. Generally, pots that are a bit larger will need water less frequently, while smaller pots will have a slightly more frequent watering schedule. Rainwater and distilled water are the best kinds of water to use for this plant, and it is best if the water you use matches the temperature of the air as closely as possible.

Allowing your Day's cymbidium to sit in soil that remains too moist for too long is one of the most common ways to kill this plant. While these plants need water frequently during active growth, they also need to live in a growing medium that drains water rapidly. When this plant experiences overwatering, it will become mushy and develop root rot. If that occurs, you should be prepared to use a pair of sterile pruning shears to cut out any roots that show signs of rot. After doing that, you should then repot your Day's cymbidium, ensuring that the container allows for drainage and that you fill the container with a fast-draining potting mix. However, Day's cymbidium doesn’t typically respond that well to excessive repotting, so it is crucial to get your watering rate right. Underwatered Day's cymbidium will begin to shrivel and feel dry to the touch. If this occurs, it is likely because the soil is drying out faster than you expected, which means you should increase your watering frequency.

During the active growth stage, which spans the spring and summer months, you should plan to water your Day's cymbidium about once or twice per week while increasing that rate to three times per week or more in the case of long periods of hot and dry weather. In the winter, you will also need to water your Day's cymbidium, but not nearly as much. A watering frequency of two to three times per month should be enough to keep your Day's cymbidium alive during the coldest months. However, if you keep your Day's cymbidium indoors during winter, you should account for the fact that indoor growing locations can cause the soil to dry quicker than usual, which may mean you need to increase the number of monthly waterings. You can use the fall as a time to gradually reduce your watering frequency from the summer rate of multiple times per week down to your reduced winter watering schedule.

There are two important growth phases that you should consider when planning the watering schedule for your Day's cymbidium. The first of those periods is the active growth period, which happens in spring and summer, and which calls for watering this plant multiple times per week. The second important growth period is the rest period that the Day's cymbidium should experience for about two to three months each year during winter. During that time, your plant will need far less water and fertilization than normal. Water about once or twice per month during this time. During the fall, you should begin to gradually reduce your watering frequency from multiple times per week all the way down to the once or twice per month rate that is appropriate for winter.

The Day's cymbidium requires a growing environment that is relatively humid. Unfortunately, most indoor growing locations will lack the level of air moisture that this plant prefers. This causes the plant and its soil to dry out more quickly than it would when growing outdoors. To combat this effect, you may want to include a humidifier in the room where you grow your Day's cymbidium. You may also need to water it a bit more frequently as well. However, while Day's cymbidiums do prefer humidity, they also require adequate air circulation as well, to prevent excessive moisture build-ups and the diseases that can result. Consider including a fan in the room where you grow this plant as well to ensure proper air circulation remains present.

Day's cymbidium requires about 3-6 hours of direct sunlight each day to thrive. However, it also needs some shade during the hottest parts of the day to prevent sun damage. Morning sunlight is ideal for Day's cymbidium, but it can also tolerate some afternoon sun if the temperature is not too hot. To provide the perfect balance of sunlight, try planting Day's cymbidium in an area that gets partial sun, such as under a tree or on the east side of a building.

If Day's cymbidium is exposed to too much direct sunlight, its leaves may turn yellow, dry out, or even burn. You may also notice that the plant wilts or becomes stunted. To prevent sun damage, make sure to give Day's cymbidium some shade during the hottest parts of the day. You can use a shade cloth or plant Day's cymbidium near taller plants that can provide some natural shade.

If Day's cymbidium doesn't get enough sunlight, it may grow tall and lanky, with sparse foliage. The leaves may also turn yellow or pale green, indicating that the plant is not producing enough chlorophyll due to lack of sunlight. To remedy this, try moving Day's cymbidium to a sunnier spot, or prune nearby foliage to allow more light to reach the plant.