6 Factors That Determine How Often You Need to Water Your Vegetable Garden
Unlike the household chores that you can schedule—like loading the dishwasher daily, handling laundry every Saturday, or taking the trash out on Wednesdays—the frequency of watering your backyard vegetable garden relies on a variety of factors, both within and outside of your control. Since over- and under-watering can prevent your plants from reaching their full potential, it's crucial that you get it right by taking into account these six questions.
How much has it rained?
Ideally, says Robert Westerfield, consumer horticulturist with the University of Georgia, "most vegetables need one to two inches of water per week." This includes both water you provide as well as rainfall, so paying attention to how the week's forecasted storms come together is your first responsibility. "Weather will ultimately determine the frequency of watering. As a gardener, you need to be aware of the weather conditions and base the frequency of watering on temperature and rainfall," adds Nancy Knauss, state master garden coordinator for Penn State Extension. This means that during some weeks, you may need to water every other day, while in rainier parts of the summer, you might not need to provide extra water at all.
How well does your soil drain?
Consider what type of soil you have in your garden. "Sandier soils are going to need to be watered more often, just by essence of drainage," says Westerfield. "The particle size is larger, so the water goes out." Richer, denser soils hold onto moisture longer, and adding two to three inches of mulch or compost around your plants can help retain moisture, too. "The more organic matter in your soil, the more moisture the soil will hold," says Knauss.
Do you have raised beds?
A bed planted in the ground will generally lose water more slowly than a raised iteration, says Westerfield. "Raised beds drain much quicker because you're normally putting in an amended, better soil that has good rooting ability—but water goes through these soils much faster," he says. "Their advantage, which is that they drain well, is also their disadvantage—they drain so fast, you need to keep an eye on them. One to two inches a week is the guidance for a traditional in-the-ground garden. A raised bed is going to require more frequent and more inches of water, most likely."
What watering tools are you using?
Watering methods vary, but the experts recommend avoiding overhead watering—say, from your hose or sprinkler—which soaks the plant's leaves instead of its moisture-hungry roots. "Applying water on the foliage of vegetable plants can increase the occurrence of certain fungal and bacterial diseases, especially when applied late in the day," says Knauss. "In addition, once you have a diseased plant, overhead watering can splash pathogens from the sick plant to the surrounding healthy ones."
Instead, they recommend incorporating a drip irrigation system that slowly waters the roots for a deeper, longer-lasting soak. These customizable systems are easy to build. "If you can put Legos together, you can put one of these kits together," confirms Westerfield. Additionally, you should allow a low-pressure stream of water to reach your plants' roots on a steady basis. They also provide homeowners with the ability to turn individual sections on or off, guaranteeing that vegetables in each section of your garden get exactly the amount of water they need.
What did you plant?
Different vegetables have different water requirements. Westerfield notes that cucumbers and sweet corn are two vegetables that require plenty of moisture—but none like to get too dry. "Many vegetables are over 90 percent water—it has to come from somewhere!" says Knauss. "A consistent supply of water is essential." Tomatoes are a prime example. "Some varieties will crack when the plants go through a dry period followed by excessive moisture," she says. "Heavy rainfall or overwatering will cause the tomato to expand faster than the skin can grow, so it splits, but consistently supplying one to two inches of water on a weekly basis reduces the chance that its flesh will be damaged."
How wet is the dirt?
The most effective way to know when it's time to water is also the simplest: Get your hands dirty. "Feel the soil," says Westerfield. "If there's moisture detected at all—so, if you can feel a little bit in there—I'd probably hold off. You don't want to keep your plant saturated and wet all the time, but if it's really bone-dry, then that's the time to irrigate again."