August has seen record heat, but that won’t stop knowledgeable home gardeners who know that now is the best time to plant fall crops: beets, carrots, kale, cauliflower, peas, lettuce, spinach, cilantro, and more.
“Fall gardening is a great time to think about irrigation and possibly upgrading your system,” said Shawn Jadrnicek, Virginia Cooperative Extension agent whose work has focused on farming in a variety of climates and landscapes. “Fall transplants need to be planted when it’s still hot in August or earlier to allow them enough time to mature before days shorten and temperatures are cooler. Tender, cool season transplants need plenty of water to get them going and keep them happy.”
Jadrnicek answered questions about when it’s best to water your garden, regardless of the time of year.
Q: What’s the best time to water a home garden?
“When to water depends on how you are watering. If you’re using a sprinkler or other type of watering system that will get the leaves wet, the best time to water is when the dew is already on the leaves. Typically, that happens overnight, starting about 11 p.m., and then dries up when the sun emerges around 8 a.m. Watering in the middle of the night is, ideally finishing before 5 a.m.”
Q: What are the risks if the leaves stay too wet?
“Fungal diseases need moisture to grow, so if you water when the dew is starting to dry on the leaves or right before the dew forms, then you are extending the timeframe the leaves stay wet and this can lead to more fungal problems.”
Q: Is the middle of the night the only time to use a sprinkler system?
“Overhead watering in the middle of the day can also be good because the plants will be dry before and after the watering event. However, you must be careful with hot water in the hose burning the plants. Keep in mind, too, that more water will evaporate during the daytime so you will lose more to evaporation. A common myth is that water will magnify the sunlight causing damage to the leaves, but this is false and probably a result of hot water coming from an idle hose sitting in the sun. Watering during the middle of the day can help cool plants and is a good technique to extend the growing season of cool weather loving plants like lettuce into the middle of summer.”
Q: How about if you have a drip irrigation system?
“If you’re using a drip irrigation system, the leaves won’t get wet and you can water anytime — but the best time with drip is when the plants most need the water, which will be when the sun is shining. With drip irrigation, you want to keep the soil around the plants close to saturation and you don’t want to push water past the root zone. Typically, this will involve more frequent watering for a shorter amount of time.”
Q: What time period settings are best for drip irrigation?
“I would water once or twice a day for a longer period of time with loam soils and up to 10 times a day for a shorter period of time with sandy soils. Either way, it’s best to use some type of automated irrigation system to make sure you’re giving your vegetables the correct amount of water at the best time.”
Q: What if there are limits on water capacity?
“If you’re on a municipal water system or have limited capacity on your well, consider watering when demand is lower. Typically, municipal systems and homes have a high demand for water in the morning when people are taking showers and baths, and irrigating during this time could reduce water pressure.”
Virginia Cooperative Extension has compiled detailed information about the ideal times and places for home gardeners to plant and grow a variety of vegetables.
Virginia Tech
