"Pallets have become a popular choice for garden construction because they are inexpensive and readily available, but exercise caution before using wood pallets in a garden. Understanding the stamps and markings on a pallet helps in making an educated choice.

Pallets are marked with these identifiers (Figure 16–9):

1. Country of origin

2. An International Plant Protection Convention (IPPC) logo, for pallets that are used and shipped internationally

3. How the pallet was treated (HT: heat treated, DB: debarked, KD: kiln dried, MB: methyl bromide, or a combination of these)

4. Possibly a numerical code and a logo identifying the inspector

If a pallet is unmarked, it may be safe to use. It is better, however, to reject a pallet without origin and treatment information.

Pallets that are safe for use in vegetable gardens

HT: Heat-treated wooden pallets manufactured in Canada or the United States undergo HT pest control treatment, which involves heating the pallet to a minimum core temperature of 56°C (132°F) for softwoods and 60°C (140°F) for hardwoods, for a minimum of 30 minutes in a kiln. Some pallets may be marked DB-HT.

DB: Debarked pallets means that the bark was cut off the wood using a scraping tool before the pallets were constructed. This has no effect on the wood of the pallet.

KD: Kiln-dried pallets have the moisture in the wood reduced to a level below 19%. This helps control warping and some fungal problems. The kilns do not necessarily reach the same temperatures (132°F) as wood that is labeled as HT.

Pallets that should not be used in vegetable gardens

MB: Methyl bromide is a pesticide used to treat pallets that ensures insects, weeds, pathogens, and rodents do not travel on shipped items. This pesticide has been linked to human health problems and ozone depletion. Dispose of them at a hazardous waste facility.

Christine