There are plenty of viable ways to supply your Common Duckweed with water. If you grow your plant in an indoor pot, for the Common Duckweeds in small pots, you can bring your potted plant to your kitchen sink. Then, use the faucet to add water to the container. By holding the pot in your hands, you should easily notice when the water begins to run through the pot’s drainage holes, at which point you can stop watering. The cold temperature will hurt the plants' root system, so please don't do this during winter or in cold climates. Most of the time, watering via your faucet is permissible for the Common Duckweed. However, if the local tap water contains a high proportion of fluorine, chlorine or salts, you should consider using rainwater or lake water. Also, since the Common Duckweed can respond well to overhead watering and watering directly into the soil, you can use a watering can, hose, or just about any tool you’d like to water it.

If you discover that you have underwatered your Common Duckweed, your first step towards remedying the situation is to give your plant some water. Water deeply until excess water runs from the container’s drainage hole, or if you grow outside, water until the soil has become entirely moist. If you find your Common Duckweed is receiving too much water, begin by reducing your watering schedule. You also want to address the soil and container your Common Duckweed grows in. If either the soil or the container makes it difficult for water to drain efficiently, your plant will likely become overwatered again. Resolve the issue by moving your plant to looser soils and/or a container with bigger drainage holes or a more porous material. Also check the location of the plant. If the plant is in places like a corner, then it is recommended to move it to a window or around a door to enhance ventilation. Making sure the plants are in a well-ventilated location can reduce the occurrence of overwatering to some extent.

The Common Duckweed is not a species that requires consistent soil moisture. Instead, it is better to allow this plant’s soil to become dry between waterings. If you are like the many gardeners who grow Common Duckweeds in containers, you can judge whether or not it is time to add water by how dry the soil within the container is. For instance, if about top half of the soil in your container has become dry, it is time to add water. You can feel it by inserting your fingers or sticks into the soil or with soil moisture meter. For those who grow the Common Duckweed outdoors, you can plan to do your watering about once every other week, provided it has not rained recently.

After waiting for the first several layers of soil surrounding your Common Duckweed’s root to become dry（top half of the soil）, it is time to add enough water to make them moist again. The amount of water it takes to achieve that goal depends on if you use a container, how large that container is, and how large your plant itself is. For a small Common Duckweed growing in a small to a medium-sized container, one to two cups may be enough to dampen the soil sufficiently. As you would expect, the volume of water you supply should increase for a larger plant. The best way to make sure your plant has received enough water is to stick your finger or a trowel into the soil and feel whether it is entirely moist. Alternatively, you can water until you see excess water draining from the holes at the bottom of your container.

Overwatering and underwatering are both bad for the health of your Common Duckweed. These two issues also manifest themselves in subtly different ways when they occur. Common Duckweed that receives too little water may begin to develop yellow leaves. Underwatering may also cause the leaf margins to become brown and brittle. By contrast, Common Duckweed that gets overwatered will often show yellow and brown marks on its leaves at the same time. Overwatering can also lead to diseases like root rot, some of which may also be visible on your plant. However, if you know the signs of overwatering and underwatering, you stand a good chance of correcting both issues.

During spring and fall, your watering schedule for the Common Duckweed will remain relatively the same, which will involve watering this plant about once every week. During summer, you may find that the hot weather causes your plant to need more water than usual, especially if it grows where there is a considerable amount of daily light exposure. In the winter, if it's hard to find some warm places for you plant, your Common Duckweed will enter a dormant growth phase, in which it will need far less water than usual. At this time, you may get by without watering your plant at all. If you do choose to water during winter, you should not do so more often than once every two to three weeks.

After planting a new, young Common Duckweed or after transplanting an older Common Duckweed, you will probably need to give this plant more water than usual. Young plants often need consistent soil moisture during the early stages of their growth to help them adapt to their new growing locations. Transplants also need more water for a brief time to overcome transplant shock. In either case, you may need to water multiple times per week until your plant has exhibited continuous healthy growth. In most situations, your water should be moderate and should never be significant enough to cause overwatering.

There are a few reasons why you may need to water an indoor Common Duckweed more often than one that grows in the ground outdoors. First, indoor growing settings tend to be drier than outdoor ones, often due to the effect of air conditioning units. While thw size of the pot and the soil determines the warer accumulating ability. Additionally, when your plant grows indoors, it will rely on you entirely for its water By contrast, Common Duckweed that grows outside can receive water from rain. If you are in an area with high rainfall, you may not have to give it extra watering. When there is not enough rain, you should water additionally to ensure that the soil does not dry out completely.

Common Duckweed requires about 6 hours of direct and continuous sunlight daily. These are desirable to help them grow healthily, and this will help them grow faster. You might also want to provide these species with supplemental light during the winter with the help of lamps. The species need several hours of unobstructed sunlight to have vibrant foliage, so you might want to place them in the brightest areas of your garden or indoor nursery.

They are suited to a full sun and don't tend to tolerate shady areas. It's best to have at least 8 inches of space for each plant especially if you’re planting a lot of them so each can get a lot of sunlight. Generally, the Common Duckweed has a high demand for direct, full, and abundant sunlight. During summers, you can place them outside in the morning sun, so they will have enough light to grow. They don't do well with partial sunlight and don't tolerate filtered or part shade. They might also not grow well when a huge tree constantly provides shade, so plant them in areas without obstruction.

The Common Duckweed should never avoid sun exposure because they seek and love the bright light. They love the sun so much that they require at least 6 hours of exposure regardless of the climate. Some areas, especially during the fall and spring, don't need protection because they require full sunlight. However, if you're located in a tropical climate or if the summer sun is too much, it's always possible to transfer the potted species inside until the temperature cools down again. Overall, you don't need to plant them near buildings, tall trees, and other structures because they need full sun for at least 6 hours.

If there's insufficient light, the Common Duckweed will not thrive. This is going to result in poor growth. Fungi and bacteria can feed on the plants' tissues, which are generally common for the plants grown in shady areas. When the plants receive too little sunlight, they tend to become spindly. They will have weaker stems because they are constantly seeking to receive light, and this can result in wilting or brown leaves. You might want to see if there are insects present or a rhizome rot in Common Duckweed as this can be another sign that they are not receiving enough sunlight. If this is the case, put them in another area where they will receive bright and direct light to see if it will make a difference.

During their growing phase, you need to expose the plants to the sun so that they don't have to stretch and grow upwards. You can avoid the process of etiolation and prevent the stems of Common Duckweed from growing weak. This is generally prevalent for those that are receiving no sun or are in a partially shaded area when they are young. When they are already established and have matured, you also need to continuously expose them to a full sun because they need photosynthesis to grow more. When they are placed inside a greenhouse or a nursery for a very long time, and you decide to transfer them into a garden, you need to gradually introduce them to the bright lights. Still, you should never suddenly place them in direct heat, especially if it's mid-afternoon. They need a period to adapt and to become used to the intensity of sunlight in your area, so give them some much-needed time.

As mentioned, the Common Duckweed needs 6 to 7 hours of direct sunlight to do the process of photosynthesis. This helps them produce enough food to grow. You can make this easier for yourself when you group them together and plant them in the same spot in your garden. This way, they will get enough of their light requirements to produce flowers, grow sturdy stems, and produce the glucose that they need for their food.

As mentioned, the Common Duckweed loves the sun, but sometimes too much can hurt it. However, too much harsh sunlight can actually burn the leaves in the summer. When planted in the ground, you might want to add to their watering schedule so they will have protection. Exposure to the blades can result in sunburn, especially when the day's sun is too strong. It's highly recommended to spray some water to cool down the leaves a bit.

You need to minimize transplanting shock, especially for the young and newly-planted Common Duckweed. These species will need time to adjust to their new environment but make sure to choose a location where they will get the full sunlight they need. The amount of sunlight matters as well as the season. Water them during the hottest days to reduce stress, and you might want to cover the young ones when the temperatures are extremely high. Row covers and shade cloths might be applicable for the younger ones, but the mature plants might not need them, especially if they already have established roots and stems. When you see that the Common Duckweed begins to lose its color, this might be because it is not receiving enough sunlight to do photosynthesis. There's not enough chlorophyll to depict a green color; if this is the case, you need to transfer it to an area receiving bright sunlight.