Water Me Pretty

By Chrissa Carlson

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If there is one chore that can be the undoing of a garden, or even the gardener, it’s watering. No matter what, our plants need water all season long, and often in volumes much greater than what the sky provides. But while your plants’ thirst is a constant, there are techniques that can make your irrigation efforts more effective and less burdensome. And by putting the water you’re using to better use, you’ll be doing our municipal water systems and the environment a favor too!

Gardening books will tell you that vegetables need about an inch of water a week, which is useful information if you have a rain gauge or if you happen to know the exact rate that water flows out your hose. Luckily, in the absence of that information, there is an easy way to figure out when your plants need water using your tactile intuition: Poke your finger into the soil; if it feels dry just below the surface, it’s time to water! If it’s moist, wait a day and check again. Roots grow deeper and stronger (a good thing, right?) if they are urged on by a little drying between waterings. And make sure when you do water it goes where it’s needed: deep into the soil, never on the leaves, where foliar moisture can promote the spread of disease.

But when should you execute this hydration evaluation? Make like the early birds and water in the AM. Watering in the morning allows water to penetrate the soil before the hot sun evaporates moisture from the surface, and allows the sun to dry any residual moisture from plant leaves. Evening waterings are a second best, though adding moisture on a humid summer night, without the foliage-drying benefit of the rising sun, can encourage the growth and spread of fungal diseases. Nobody likes those.

If you’re going to go to the effort to get that water into the ground, put out a little effort to keep it there. Mulch keeps the soil moist between waterings. Really, try it!—spread some straw or leaves on the surface of the soil around your veggie plants (save the wood chips for the ornamental beds), and after a dog day, compare soil moisture under the mulch to exposed areas. You may extend the interval between waterings by a day or more!

Where you get your water can have a big impact on your plants and the planet. Water from the hose is okay, although the residual salts from the treatment of municipal water can eventually build up in the soil. Rainbarrels offer a solution to this problem, harvesting rainwater that would otherwise head down the storm drain to use during dry times. However, the jury is still out on the safety of watering edibles with water that has flowed across rooftops and sat in stagnant silence, potentially picking up contaminants and breeding funk. To help you decide for yourself, contact the Home and Garden Information Center at University of Maryland Extension for more information on this topic.

If you’re going to use a rain barrel, think through the installation to ensure that water is not only captured, but also used. If it’s not easy to extract the water from the barrel, you might end up saving one barrel-full of water from the storm drain, but then never put it to use in your garden. Build a sturdy stand to elevate the barrel three feet and you’ll have plenty of pressure to water from the barrel with a hose (or easily fill a watering can). Alternatively, you can buy inexpensive pumps that put some oomph behind the liquid.

If you’d rather set it and forget it, drip irrigation uses less water more effectively, and can change your relationship with your garden. Systems are typically equipped with a timer, allowing you to turn a dial and know your plants are getting the drink they need, and freeing your hands up to tend to other garden chores. Drip irrigation systems are not necessarily expensive; a family garden can be outfitted for less than $200. Urban Farmhouse plans and installs drip irrigation systems, and works with our clients to teach them how to use and adapt their system to meet water needs in their landscapes. Contact [email protected] to discuss your irrigation options!