Morning vs evening watering: Which is better for your plants during extreme summer heat and why it matters

As summer temperatures rise, it has become difficult to determine whether watering plants during the morning or evening is more beneficial. Although either time is much better than watering midday, watering plants in the morning is undoubtedly healthier for most of them. The time you choose to irrigate your plants may determine how healthy your crops are in terms of growth.

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The best time to water plants is when they just start waking up and getting ready to go about their daily activities. It is recommended to water plants at least between 5 a.m. and 9 a.m.

Watering in the morning also helps plants get ready for heat stress. By having the roots drink up water before temperatures rise, plants will find it easier to conduct physiological functions like photosynthesis and nutrient transportation. It might be particularly useful during heatwaves where a lot of moisture may be lost from the leaves. A huge advantage of early watering is the amount of time that the leaves and stems will take to dry off. Dried leaves and stems will protect plants from fungi and mildew growth.

Gardeners tend to stay away from watering during the day since evaporation levels are at their peak during this time. Thus, a good part of water can evaporate, rendering the watering ineffective. Interestingly, while most people believe that midday watering causes leaf burning by focusing sunlight through water droplets, this is only a popular gardening myth. In reality, midday watering simply wastes water with little effect on the plant itself.

Night-time watering is not bad per se and can prove a good solution if mornings are not an option. Indeed, during the hottest summer days, watering in the evening helps to minimize water loss through evaporation. However, the disadvantage is that plants will remain wet all through the night. Plants that are exposed to wet leaves and cooler temperatures at night might contract fungi diseases. Additionally, overwatering the plants during the night may expose them to root problems.
In cases when watering at night cannot be avoided, it is advisable to water the soil and not the foliage. Moreover, water should be administered well before sunset in order to give plants an opportunity to dry up a bit.

In extreme cases when temperatures soar very high, plants will need watering irrespective of the timing. Instead of watering frequently, deep watering should be encouraged. Another method to maintain soil moisture and lower its temperature is using mulch surrounding the plant. Mulches like straw or bark work well in the heat conditions.

Container plants need special treatment because they dry out much more quickly than garden plants. During extreme heat, there may arise a situation where potted plants need watering twice in a day.

It seems clear that if one must water only once a day during extreme summer heat, the preferable time is in the morning. This will provide plants with much-needed moisture before the heat of the day, minimizing evaporation and decreasing the chance of disease.

Disclaimer: This is intended for general informational purposes only. Watering needs can vary depending on plant species, soil type, climate, humidity levels, and local weather conditions.