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Horticulture hydration

News source/writer: Andrew Holsinger, 217-532-3941,

It's not rocket science; we all know that plants need water to thrive. But Andrew Holsinger wants to give gardeners a refresher on the ins and outs of garden hydration.

"Many environmental conditions factor into plant survival," says Holsinger, a University of Illinois Extension horticulture educator. "Hydration is one of the most important of those factors."

Plants vary in their moisture requirements, but as a general rule, vegetable crops require at least an inch of water per week. Excessively hot or windy days may require more frequent irrigation because more water is lost from the plant. Holsinger says too little water can cause not only drought stress but also increased disease or insect susceptibility.

Mulch can help conserve moisture and reduce the plant's demand for more water. For plastic mulches, the plants will need to be irrigated regardless of rainfall events. Water does not readily penetrate beneath the plastic, so it is often necessary to add drip irrigation under the plastic.

"Putting moisture in the right place, where the plant is located, is also a way to reduce weeds because you're not providing water where it isn't necessary," Holsinger says.

Drip irrigation delivers water to the base of the plant instead of on its foliage. Gardeners should avoid excessive water application on leaves to avoid fungal pathogens and diseases, some of which can cause wilting. Surprisingly, overwatering can also cause wilting, so be sure to check the soil before watering.

"For most plants in the garden or landscape, a well-drained soil is required. However, in some spaces where drainage may be an issue, a raised bed can help increase drainage," Holsinger says. "Raised beds can be used for both ornamental and edible crop plantings."

Containers can be great for growing, but they need adequate drainage holes. A more frequent watering schedule is required for containers, as they tend to dry more quickly than garden beds.

"It's rare in Illinois to see consistent precipitation throughout the season, and an attentive gardener is aware of it," he says. "Your watering schedule will have to be adjusted over the season."

As plants mature, they require more water. Therefore, if you have a limited amount of water available to dedicate to your garden, you may want to plan. Setting up zones based on water use can help to distribute water at appropriate levels to plants based on their cultural requirements.