The dry lot: how big it should be, where it goes, and what to put under it.

Published 14 October 2026

What a dry lot is for

eXtension separates two ideas that people often run together. A dry lot is an exercise paddock where horses can go during high-stress periods so the pasture is not overgrazed, including heavy rain and drought. A sacrifice lot is a small enclosure sacrificed for the benefit of the rest of the pasture, used in winter and whenever pastures are saturated.

Either way the job is the same: take the traffic off ground that cannot take it. The rotational grazing guide and the acres per horse guide both lean on it, because no pasture figure holds up if the grass never gets to recover.

Washington State Extension’s small-acreage guidance for livestock adds timing: confine animals in winter and early spring, before pasture drops below 3 inches, and create the area only after the ground has dried and firmed.

How big

eXtension says a dry lot should provide a minimum of 400 to 500 square feet per horse, increasing in proportion as the number of horses grows. Its pasture-planning guidance puts the minimum at 500.

• 1 horse: 400 to 500 square feet
• 2 horses: 800 to 1,000 square feet
• 4 horses: 1,600 to 2,000 square feet
• 6 horses: 2,400 to 3,000 square feet

Those totals are simple multiplication. For comparison, Washington State’s livestock guidance runs from a 20 by 20 foot area for one animal, which is 400 square feet, to a long narrow paddock of 20 by 100 feet for several. It notes that larger areas give animals room to move and reduce the risk of injury.

Where it goes

eXtension puts a dry lot next to the pasture, typically near the barn, with a common gate opening into each pasture. That is what makes moving horses on and off in wet weather easy enough that people actually do it.

Washington State adds the site rules: high ground, near the barn and manure storage, away from wetlands, streams, ditches and wells, and slightly sloped so water drains. None of the sources I read give a numeric slope, so ask your contractor or conservation district for one that suits your soil.

Put water at the opposite end from the shelter. eXtension notes this encourages horses to move and limits erosion around the trough. In winter, keeping that water open is its own job.

What goes under it

Bare soil turns to mud, and the fix extension services describe is the same in outline: excavate, separate the soil from the stone, then build up. eXtension’s guidance for high-traffic areas gives the layers:

1. Dig out 6 to 8 inches.
2. Lay geotextile, a porous filter-type fabric, or a plastic grid. Spread it smoothly with few wrinkles so the load is shared evenly.
3. Add 4 to 6 inches of No. 4 crushed limestone over the fabric.
4. Optionally lay a second fabric between the large rock and the fine layer to keep water moving.
5. Finish with 2 to 3 inches of fine material: dense grade, screened lime, or sand.

Washington State agrees on the principle and gives two more rules. Cover the fabric with at least 6 inches of footing, overlap fabric edges by at least 6 inches, and use about twice as much footing as the mud is deep. If you are fighting 3 inches of mud, plan on at least 6 inches of cover.

For heavy-traffic areas, eXtension’s dry-lot guidance suggests crush and run covered by screenings, ground limestone or number 78 gravel. Crush and run is also used to raise low areas.

The sources describe the layers a little differently and none of them can know your soil, so treat the depths as a range and check them with your local extension office.

Keep the water out

A lot that floods is no better than a muddy field. Both eXtension and Washington State point at the same culprits:

• Roof runoff. eXtension notes that rain running off barn roofs can worsen mud if it is not directed away from high-traffic areas. Washington State recommends gutters on barns and sheds.
• Water coming from uphill. French drains, swales and berms can divert it around the lot.
• Water leaving the lot. Washington State recommends a vegetated filter strip or swale on the downhill side, and eXtension suggests a grass strip of about 25 feet around a sacrifice lot as a runoff filter.

Keeping it working

A built-up lot can fail slowly, and manure buildup is one cause the sources name. eXtension says to remove manure and old hay from a sacrifice lot every 1 to 3 days. Washington State explains why it matters on stone and sand: buildup blocks water from soaking through over time.

What these sources do not settle

None of the text I could read gives a slope in numbers or a lifespan for the surface. Soil type and rainfall change what works, and rules about runoff near water vary by place. A short call to your county extension office or conservation district is worth making before you excavate, not after.