Raised garden beds are one of the best ways to get yourself and the kids out into the garden, growing your own food. Usually constructed of wood, raised beds are not only visually appealing, they make cultivating spring, summer and fall produce easy and fun. When choosing between fir and poplar with which to build your bed, keep the pros and cons of each in mind.
Raising the Raised Bed
Raised-bed gardening offers several advantages, including better drainage, moving desirable plants further from possibly weed- or disease-infested garden soil and reducing maintenance. Better drainage also expands the growing season by allowing earlier spring planting due to warmer soil, and better spring and fall cultivation because soil is not inundated with rainwater. Nor is it difficult, though you do want to be sure to use a suitable wood or you may end up replacing your beds every few years.
Poplar wood comes from the poplar tree (Liriodendron tulipifera), also known as the tulip poplar or the yellow poplar for its large, cup-shaped yellow flowers that bloom in May and June. The tree is native to eastern North America and hardy in U.S. Department of Agriculture plant hardiness zones 4 through 9. Though its wood is generally strong and has been used for lumber and dugout canoes, it is only somewhat durable, and can be susceptible to rot and insect attack. Be careful when first using it, as it can sometimes cause skin, eye and lung irritation, though rarely.
Firs such as Douglas fir (Pseudotsuga menziesii) are native to western North America and are adapted to cool to cold climates, hardy in USDA zones 4 through 6. An evergreen, Douglas fir is good for lumber, but not necessarily as good for raised bed gardening. While it's a bit sturdier outdoors than poplar and resists rot somewhat better, it can be very susceptible to insect attack.
While initially any wood will work to build a raised garden bed, some break down much faster than others. Because both fir and poplar woods are moderately durable but may be susceptible to insect attack, they are not the best choices for raised beds if you have another option. Trees like red cedar (Juniperus virginiana), for instance, are not usually susceptible to insects because of their strong smell, and are very durable in the garden. Hardy in USDA zones 2 thorugh 9, the lumber from this tree is a popular choice.