You may find the surface of your container’s soil completely dry but the roots are still in moist soil. It only takes a little sun and breeze to dry out the surface of the soil quickly, especially in smaller pots. If you were to water whenever the soil appears dry on the surface you would likely keep the potting mix wet all the time. Instead of relying on the appearance of the soil alone, take a moment to determine whether it needs water by examining the soil moisture below the surface.
Insert your finger into the potting mix and note the temperature and feel of the soil below the surface. If it is cool and moist, it is safe to assume it does not need more water right now. However, if it feels dry at a couple inches down and the container seems light, it is a good idea to water. Knowing the type of container you are using will help you understand why it may take longer or shorter to dry out. For example, a small container in full sun may take far less time to dry out than a larger container in partial shade.
Observing the condition of the plant can be helpful but should never be used as a sole indicator. Wilted or limp leaves might signal dry roots, but they can also indicate that roots are staying wet and not functioning properly. The soil moisture, drainage holes, and how recently the plant was watered should all be considered. If you recently watered the plant thoroughly, and the soil is still wet after several days but the leaves are still wilted, adding more water is unlikely to help.
To get a better sense of when your container needs water, pick one container and observe it closely over a period of several days. Determine how deep your container’s soil gets when you check it on a daily basis and see how it feels. See if the container gets lighter over time and how the leaves appear in the morning versus the afternoon. Then water the container well, allowing water to drain through the bottom, and start observing when the container needs water again. You may find that it takes longer or shorter than you expected. Now, when you water that container again, you’ll have a better idea of when to water it next time. You can do the same with other plants in other containers to get a general idea of when they need water. Just remember that not all containers will dry out on the same schedule.
Water deeply when watering is required. Allow water to flow out the bottom of the container and empty any tray underneath. Make sure the container has drainage holes so water doesn’t remain trapped in the bottom and cause rotting. It’s best to avoid sprinkling the soil on a frequent basis. Wait until the soil is drier before adding water again. It goes without saying that the hotter and sunnier the weather, the more frequently the plant will need water. Windy conditions, larger plants, or plants that are actively growing will also use more water. Conversely, cooler temperatures and overcast skies will decrease the rate at which the plant uses water.
Instead of following an arbitrary rule about how often to water your vegetables, such as “water every 2 or 3 days”, get in the habit of checking the soil and the container before watering. When you look at the container’s soil, the weight of the container, the drainage holes, and your plant’s overall appearance, and factor in the weather, you’ll have a much better idea of whether your plant needs water. Once you get in the habit of checking the container and the plant before you reach for the hose or watering can, you won’t feel like you have to force your plants into a specific watering schedule.
