Plant tissues physiologically respond to stress in many ways. One sign your plant is stressed is wilting, or the loss of rigidity in the non-woody part of the plant. If plants are wilted for too long, they will eventually die.

Recent droughts over the last few summers have made wilting a common issue. Ontario farmers have seen lost profits as fruits and vegetables are unable to grow properly. Corn and soybean farmers found wilted plants leading to lower than expected production. Last summer in Vancouver the city called on residents to help water city trees and report any that look unhealthy. Summer 2018 was one of the driest Vancouver summers in nearly a century.

As we get through another summer, it’s important to understand why plants wilt, what it means and how to prevent it.

Not enough water

Even non-gardeners know that plants need water to survive. Lack of water changes the internal pressure of the plant’s cells, making the plant smaller and less full. The decrease in size and surface area is a survival tactic to reduce the impact of water loss.

Low water availability can occur for several reasons:

  • Drought conditions causing soil to be too dry
  • Low temperatures that prevent the plant’s vascular system from functioning properly
  • High salinity causing water to diffuse from plant cells
  • Too much water causing overly saturated soil (see below)
  • Disease-causing microorganisms clog the plant’s root system

Potted plants have less soil volume than plants in the ground, and therefore need more watering. Potted plants should be watered to the point that water drains all the way through the pot. Plants have different water requirements, so it’s always good to do your research.

Too much water

Seemingly contradictory, too much water can lead to wilting because it prevents the soil from getting water to the plant. Overly saturated soil prevents roots from obtaining oxygen for cellular respiration, making them unable to transport water to the plant. Too much water near plant roots can cause root rot and other fungal diseases that lead to wilting. Reducing watering and making sure plants have proper soil drainage will help prevent overwatering.

Poor lighting

Plants can wilt due to too much or too little lighting. While some plants require six hours of sunlight a day, others prefer shade to grow. Plants with too little light grow weakly, developing pale foliage. Plants can develop sunburn, where their leaves turn yellow or brown and eventually wilt and die.

Insect damage

Some insects use plants as a drinking fountain, sucking out a plant’s juices. Common garden pests like aphids, mites and squash bugs are all plant dehydrators. Plants who are already lack water are especially susceptible.

Bacteria and fungi

When your plant hosts disease-causing microorganisms, they compete for the plant’s resources. A common fungal disease is verticillium wilt, causing affected plant leaves turn yellow and wilt. Sending a soil sample to the lab can help determine what’s causing plant wilt.

Wilting might be a natural process that is not always permanent. To learn more about preventing plant wilt, contact one of the team at Soil Advocates or 289-221-0164.

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