February 2018

It’s the heat AND the humidity taking a toll in Indiana gardens

<p>Curling leaves do not always mean a plant needs to be watered. (C) Jo Ellen Meyers Sharp</p>

Curling leaves do not always mean a plant needs to be watered. (C) Jo Ellen Meyers Sharp

It’s painful to watch our plants struggle in the smothering heat and acting on our instinct can cause more problems than we cure.

Plants respond to hot weather or the lack of water in similar ways. The leaves curl, turn upside down or flatten close to the plant stem. The plant is trying to conserve moisture by reducing the parts exposed to the sun and heat.

We see this reaction on many, many plants, including trees, shrubs, flowers and food crops. Hydrangeas, impatiens, tomatoes and coneflowers are just a few examples.

Unfortunately for the plants, we respond to these symptoms with the same treatment — water, water and more water and end up drowning the plant’s roots or causing top growth to rot off.

We should water only if we know the plant needs water. If a plant’s leaves return to normal when out of the sun or during lower night temperatures, they probably don’t need water.

Another test is to check the soil. For large plants, such as shrubs and perennials, stick a trowel, spade, knitting needle or soil probe into the ground. If the instrument comes out with damp soil, don’t water. If the instrument comes out dry, water deeply.

For smaller plants, such as annuals in the landscape or in pots, rely on your index finger. Stick your finger in the soil and if it feels dry to the second knuckle, water.

Containers should be watered until the water runs from the bottom. Sometimes containers dry out completely and water drains immediately from the pot without dampening the soil. Place the pot in a bucket or tub of water to allow the soil to wick up the moisture. Or, place some ice cubes on the soil surface, away from the stems of plants. The soil is re-moistened slowly by the melting ice.

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