Hay soaking is one of the most helpful—but often misunderstood—tools in horse nutrition management.

For some horses, a simple soak can make a big difference in their overall health and comfort, especially those managing conditions like equine metabolic syndrome (EMS), insulin resistance, a history of laminitis, Cushing’s disease (PPID), or respiratory issues like heaves (RAO).

Knowing when to soak hay, how long to soak it, and the right way to do it can help you better support your horse’s individual needs. In this article, we’ll walk you through everything you need to know about soaking hay and how it can fit into your horse’s care routine.

Soaking hay can be a valuable tool in your horse’s care routine, but it’s important to understand that it’s used for two different reasons—and the right approach depends on your horse’s individual needs and health concerns.

1. Lowering Sugar and Starch Content (NSC Reduction)

Hay naturally contains water soluble carbohydrates (WSCs), including sugars and fructans. In some horses, especially those with metabolic concerns, these carbohydrates can contribute to insulin spikes and make managing their condition more challenging.

Soaking hay allows some of these water soluble sugars to leach out into the water, reducing the forage’s non-structural carbohydrate (NSC) content.

This can be especially helpful for horses with:

• Equine metabolic syndrome (EMS)
• Insulin dysregulation
• A history of laminitis
• PPID (Cushing’s disease) with insulin resistance
• Easy keepers who gain weight easily

For these horses, lowering sugar intake can be an important part of a balanced nutrition plan.

2. Reducing Dust, Mold Spores, and Allergens

Soaking hay can also help horses with respiratory sensitivities. Even high quality hay can contain small amounts of dust, mold spores, and other particles that can irritate a horse’s airways.

For horses with conditions like equine asthma (formerly known as heaves or RAO), dampening hay helps reduce the amount of dust and allergens released into the air during eating.

This can create a cleaner and more comfortable feeding environment that makes breathing easier.

This is where a lot of horse owners get it wrong—because more soaking isn’t always better:

When it comes to soaking hay, water temperature can make a big difference.

Research in equine nutrition has shown that warm water is much more efficient at removing water soluble sugars than cold water. A 30 to 60 minute soak in warm water can remove a similar amount of sugar as a 12+ hour soak in cold water.

For horses that need tighter control of NSC (non-structural carbohydrate) levels, or for owners who don’t have hours to wait, warm water can be a practical option.

However, keep in mind that soaking time also matters. Leaving hay submerged for too long—especially more than 12 to 16 hours or during warm weather—can increase the risk of bacterial growth and mold.

The goal is to find the right balance: remove excess sugars while still keeping your horse’s forage fresh, safe, and nutritious.

Soaking hay may seem simple, but a few small details can make a big difference in keeping your horse’s forage safe, effective, and consistent.

Follow these steps to get the most benefit from your soaking routine:

1. Weigh Your Hay Before Soaking

• Start by weighing your hay before it goes into the water.
• Soaking can remove some dry matter along with sugars, so knowing the original weight helps you maintain consistent forage intake and feeding amounts.

2. Fully Submerge the Hay

• Use a hay net, muck bucket, stock tank, or dedicated soaking container—whatever works best for your setup.
• The hay should be completely covered by water to allow the sugars and other soluble materials to leach out properly.

3. Use Enough Water

• Make sure there is enough water for the hay to soak fully.
• A general guideline is to use about 2 to 3 gallons of water per pound of hay, allowing enough room for proper sugar migration.

4. Time Your Soak

• Set a timer instead of guessing.
• Consistency matters, especially for horses that need careful management of sugar intake.
• Keeping your soaking routine the same helps you get more predictable results.

5. Drain Thoroughly

• Once soaking is complete, don’t forget to drain the hay well.
• If possible, give it a quick rinse before feeding.
• The leftover soak water contains concentrated sugars, dust, and debris, so it should never be reused or offered to your horse.

6. Feed Soaked Hay Promptly

• Soaked hay spoils more quickly than dry hay, especially in warm weather.
• Try to feed hay within a few hours after soaking.
• Avoid letting soaked hay sit out for extended periods where mold and bacteria can develop.

7. Dispose of Soak Water Properly

• The leftover water contains a high amount of organic material and dissolved sugars.
• Avoid dumping it near barns, stalls, or areas where it can collect and attract insects.
• Instead, direct it toward appropriate drainage areas or a compost system when possible.

Soaking your horse’s hay can be a helpful tool, but a few common mistakes can reduce the benefits or create new problems.

Keeping these tips in mind will help you maintain safe, nutritious forage for your horse:

1. Soaking Too Long in Hot Weather

• Warm temperatures speed up bacterial growth, especially when hay is left soaking for extended periods.
• Once temperatures climb above 70°F to 75°F (21°C to 24°C), it’s important to shorten soaking times and feed the hay as soon as possible after draining.

2. Reusing Soak Water

• Once hay has soaked, the water contains removed sugars, dust, and organic material.
• This water should never be reused for fresh hay or offered to livestock.

3. Assuming All Hay Needs the Same Treatment

• Not all hay has the same nutritional profile.
• Grass hays and legume hays like alfalfa can vary widely in their natural NSC (non-structural carbohydrate) levels.
• If sugar reduction is a major concern, having your hay tested is much more accurate than relying on assumptions.

4. Forgetting About Winter Challenges

• In colder climates, freezing temperatures can make soaking hay difficult.
• Tubs, buckets, and hay nets may freeze quickly, creating an extra challenge for winter feeding routines.
• Some horse owners choose alternatives like steaming hay during colder months.

5. Overlooking Nutrient Loss

• Soaking hay doesn’t only remove sugars—it can also reduce certain nutrients, including minerals like potassium and a small amount of protein.
• Horses receiving soaked hay long term may benefit from a balanced vitamin and mineral supplement to help fill nutritional gaps.

While soaking and steaming hay are often mentioned together, they actually serve different purposes. Choosing the right method depends on what you’re trying to address—whether it’s lowering sugar levels or improving respiratory health.

Steaming Hay

Hay steaming uses heat and moisture to help reduce dust, mold spores, and bacteria, making it especially helpful for horses with respiratory sensitivities.

Compared with soaking, steaming is generally more effective for improving hay hygiene.

However, steaming is not a reliable method for lowering sugar content. It does not significantly reduce NSC (non-structural carbohydrate) levels and, in some cases, may even concentrate soluble sugars near the surface of the hay.

Soaking Hay

Soaking is the better choice when the goal is reducing water soluble carbohydrates and managing sugar intake.

It can be especially helpful for horses with metabolic concerns, but it is not as effective as steaming when it comes to reducing airborne particles like dust and mold.

For horses dealing with both metabolic concerns and respiratory issues, some owners may use a combination approach or work with their veterinarian or equine nutritionist to determine the best feeding strategy.

At the end of the day the right choice depends on your horse’s individual needs, health conditions, and their overall diet plan.

If you’re managing a horse with metabolic concerns or a history of laminitis, soaking hay without knowing its starting point is really just a guess.

A hay analysis can give you valuable insight into your forage’s baseline NSC (non-structural carbohydrate), sugar, and starch levels, helping you determine whether soaking is needed and how much of a difference it can make.

For horses that are insulin resistant or prone to laminitis, many nutrition professionals recommend choosing hay that tests around 10% to 12% NSC or lower on a dry matter basis.

Soaking can be a helpful tool for reducing sugar levels, but it works best as part of a bigger nutrition plan—not as a replacement for selecting appropriate hay from the start.

Knowing what’s in your hay puts you in a much better position to make informed feeding decisions for your horse’s health.

Soaking hay is a simple and affordable management tool that can offer real benefits when it’s done correctly.

The key is matching your soaking method to your horse’s specific needs and using the right combination of time, temperature, and hygiene practices.

For most sugar reduction goals, a warm water soak of 30 to 60 minutes can be an efficient option.

Shorter cool water soaks may help reduce dust and airborne particles, while horses dealing with both respiratory and metabolic concerns may benefit from a combination approach, such as pairing soaking with steaming or evaluating their hay source.

And iff your horse has metabolic issues, insulin resistance, or a history of laminitis, it’s always best to work with your veterinarian or an equine nutritionist.