Crown hydration is winter damage that happens to your lawn and plants during periods of thawing and rapid refreezing caused by sudden temperature shifts.
Crown hydration is the least predictable and often most devastating cause of winterkill in turfgrass. Winterkill is the death of plants like grass caused by harsh winter conditions.
How does crown hydration happen?
Before we discuss how crown hydration kills turf, we should go over what exactly it is. Crown hydration happens when grass absorbs water during a warm spell in the winter that is quickly followed by a dip into freezing temperatures, typically happening in the transition from late winter to early spring.
The water then freezes in the turf’s crown. Crown hydration damages grass at the cellular level in two ways:
- Destroys cells from the inside if the ice forms within the cells. Water expands when it freezes, so it ruptures the cells from within.
- Draws moisture from the cells if the ice forms around and outside the cells. The cells will die from dehydration if too much water is drawn out of them.
The crown is a crucial part of a grass plant, as it produces new growth. If enough cells in the crown are damaged, your grass will die.
The warmer temperatures can also start the de-winterization process in your grass too early – in other words, your lawn comes out of dormancy before it’s meant to. This makes it even more susceptible to crown hydration.
Grasses with low cold tolerance are more vulnerable to crown hydration. According to the Michigan State University Extension, annual bluegrass (used in golfing greens and fairways) is the grass most susceptible to crown hydration. In most lawns, annual bluegrass is a common cool-season weed.
How to identify crown hydration damage
Because crown hydration is one form of winterkill, crown hydration damage is the same as winterkill damage. Here is how to identify it:
- Yellow or brown grass
- Patches of dead grass
- Thinning turf
However, you will only really find out the extent of the damage once the snow has fully melted.
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Is there anything you can do to prevent crown hydration?
Crown hydration is one of the least predictable causes of winterkill, and there’s not much you can do to definitively prevent crown hydration. You can’t control how much snow and ice you’re gonna get, nor can you control if your area gets a warm spell and sudden freeze.
Here are the steps you can take to prevent crown hydration, though:
- Fix drainage issues as poorly-drained areas are the most susceptible to crown hydration. Standing water will make your grass more saturated than normal, which leads to worse crown hydration damage. You may need to level your lawn to do this.
- Dethatch your lawn before the grass becomes dormant.
- Don’t mow too low in the fall.
- Only use potassium fertilizers (avoid nitrogen-heavy ones) when fertilizing cool-season grass in late fall. This will encourage strong roots without encouraging your turf to grow close to dormancy. Grass that grows when it’s supposed to go dormant will have new growth that is more susceptible to crown hydration.
- Grow a strong lawn by taking good care of your grass the rest of the year. Strong grass is more resilient.
- Don’t force your lawn to come out of dormancy early by feeding it with quick-release fertilizer when it’s dormant. This can encourage your grass to take in water, leaving it susceptible if there’s a sudden freeze.
You can read our article about preventing winter lawn damage to learn more.
Related articles:
- “What is Winter Fertilizer?”
- “When to Dethatch Your Lawn”
- “Last Mow of the Season”
- “How Short to Cut Grass Before Winter”
How to fix crown hydration damage
Your plan of action for fixing crown hydration damage will depend on the extent of the damage:
- Care for your grass as you normally would in the spring months if the damage is minimal – just a few small patches of bare dirt or thinning turf. You can read our article, “Tips for Spring Lawn Care” for a guide on how to properly care for your lawn in the spring.
- Overseed your lawn if there is moderate damage to your turfgrass. Lay sod if the damage is extensive.
- Reseed your lawn if your lawn is severely damaged, like if it has patches of grass amidst dirt.
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FAQs
The crown is the base of perennial grass plants where all growth comes from. That’s why your grass can die if the crown gets heavily damaged.
Crown hydration is a type of winterkill. There are many other types of winterkill, such as winter desiccation.
The other types of winterkill include:
• Winter desiccation
• Direct low-temperature kill
• Ice sheets
• Snow mold (comes in gray and pink varieties)
Call a pro for a healthy and resilient lawn
One of the best ways to protect your lawn from crown hydration – or any damage, really – is by practicing good lawn maintenance throughout the year. If you don’t have the time or energy to care for your lawn, Lawn Love’s local pros can handle the mowing, seasonal fertilization, and even weed control. Hire a Lawn Love pro today.
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Main Image Credit: YARphotographer / Adobe Stock Free / License
