Moisture content plays a critical role in how wood pallets perform, from strength and stability to mold resistance and export compliance. Whether you’re sourcing hardwood or softwood pallets, understanding how moisture levels vary by species and drying method can help you make smarter, more cost-effective decisions.
In this article, we will explain the differences in moisture content between hardwood and softwood. We will also discuss how these levels change during drying processes. Finally, we will look at what this means for your supply chain and your budget.
Mold Prevention Starts with Moisture Control
Mold is a common worry for pallet buyers. This is especially true in the food, chemical and pharmaceutical industries, because hygiene and product quality are very important. The key to mold prevention is moisture control.
According to Virginia Tech’s Center for Packaging and Unit Load Design, wood must be dried to below 19% moisture content to reliably prevent mold growth. This threshold is essential in warm, humid environments where mold can develop within 48–72 hours on green or air-dried wood.
Moisture Content: The Basics
Moisture content (MC) is the percentage of water in a piece of wood compared to its dry weight. For pallets, MC directly affects:
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- Strength and rigidity
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- Dimensional stability (shrinkage, warping)
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- Nail retention
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- Mold risk
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- Compliance with ISPM 15 pallets for export
Hardwood vs. Softwood: Moisture Content by Stage
| Stage | Species | Moisture Content* | Time to Reach* | Cost |
| Green | Softwood (e.g., pine) | ~100% -220 | Immediate – fresh cut | Low |
| Green | Hardwood (e.g., oak, maple) | ~85% -140% | Immediate – fresh cut | Low-Moderate |
| Air Dried | Softwood | ~20–35% | 1″ thick: 60-120 days 2″ thick: 150-240 days |
Low-Moderate |
| Air Dried | Hardwood | ~20–30% | 1” thick: 50-200 days 2″ thick: 180-320+ days |
Moderate |
| Kiln Dried | Softwood | ~15-19% average Const. grade: 15-19% |
4 days – 3 weeks faster schedules possible |
Moderate |
| Kiln Dried | Hardwood | ~8% MC average Furniture grade: 6-8% |
4 days – 3 weeks slower schedules to prevent defects |
Very High |
Source: USDA Wood Handbook and Various University Extension Offices
*Moisture content and dry times vary by climate and species
Why Moisture Content Matters in Pallet Applications
1. Green Wood: Higher Moisture, More Movement Over Time
Green hardwood and especially softwood often contain high moisture levels—sometimes exceeding 100%. Hinton’s green pine pallets are made to meet performance standards. However, moisture naturally evaporates over time. This can cause shrinkage, warping, or surface cracking as the wood dries. These effects don’t prevent use but should be considered in environments where dimensional stability is critical.
2. Air-Dried Wood: Improved Stability, Less Control
Air drying gradually lowers moisture content and can offer improved consistency over green wood. However, the final moisture level depends on time and local climate conditions. In humid areas, wood can hold more moisture. This is not ideal for automated handling systems with strict guidelines.
3. Kiln-Dried Wood: Controlled, Stable, and Mold-Resistant
Kiln drying reduces moisture content to controlled levels—typically ≤19% for pallet-grade softwood—which helps to:
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- Improve strength and load consistency
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- Minimize warping and cracking
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- Lower the risk of mold development
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- Comply with ISPM 15 pallets for export-ready compliance
The Time and Cost Trade-Offs of Pallet Wood Drying Methods
Moisture content levels and relative cost impact for green, air-dried, and kiln-dried softwood and hardwood used in pallet production.
Moisture content affects pallet performance. It also impacts how long lumber must sit before use. It influences the amount of yard space and inventory it takes up. Additionally, it can lead to hidden costs in handling or freight.
Choosing between green, air-dried, or kiln-dried wood is not just about the price. It is also about matching the materials to how they will be used.
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- Green Lumber: Hidden Costs in Weight and Mold Risk: Green lumber may seem cheaper at first. However, its high moisture content makes it heavier. This increases freight costs and handling strain. It is also more likely to grow mold, especially in humid areas. As it dries after assembly, it may shrink, crack, or warp. This can cause problems with storage, automation, or stacking.
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- Air Drying: Takes Time and Space: Air drying is a cheap, natural way to remove moisture. It works by using air and sunlight over time. However, drying can take 4 to 12 weeks or longer, depending on wood species, board thickness, and climate. During this time, lumber ties up yard space and is vulnerable to inconsistent results.
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- Kiln Drying: Quick and Controlled: Kiln drying uses heat and airflow. This process reduces moisture to specific levels, which are 19% or lower. This process takes only 2 to 5 days and ensures consistency, no matter the outside conditions. While it involves higher energy and equipment costs, it minimizes storage time, improves quality control, and supports mold-sensitive and export applications.
Choosing the Right Wood and Moisture Level
Whether your operation calls for heavy-duty hardwood pallets, cost-efficient green pine, or KD pine for ISPM 15 pallets or hygiene-sensitive environments, Hinton Lumber delivers the right solution for your application. We supply a full range of pallet options, engineered to meet your moisture, strength, and compliance requirements.
For industries where mold prevention is critical, like food and pharmaceuticals, our heat-treated, kiln-dried softwood pallets offer added protection and performance. Each load is crafted using carefully selected lumber, which is treated to keep moisture levels at or below 19%. This helps lower biological risks and extends the service life.
Moisture content matters. Fresh-cut lumber may look the same, but its moisture level inside can greatly change how a pallet works in real life. Choosing kiln-dried pine with controlled moisture helps ensure quality from production to delivery. This is especially important when mold resistance and safety rules are must-haves.
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