Gardening Articles: Care :: Tools & Equipment
The Inside Scoop on Shovels (page 2 of 4)
by David Lyon
The earliest digging tools were fashioned completely from wood. Probably the oldest known is a digging stick from 60,000 years ago unearthed in Zimbabwe. Shovels with separate blades begin to shup in the archaeological record about 5,000 years ago. Dr. Lucy Lewis Johnson of the anthropology department at Vassar College says shovels made from the shoulder blades of animals were used in northern European flint mines around 3,000 B.C. Too soft for digging, shovels of bone were probably used to remove material loosened by a pick or mattock.
Thanks to iron metallurgy, devices very similar to both our spade and shovel were going strong by Roman times. When Cato the Censor (234-149 B.C.) compiled the world's oldest surviving tool catalog, he specified that a commercial olive grove of about 150 acres required eight heavy spades, four smaller spades and an unspecified number of shovels (along with assorted axes, scythes, wedges, manure baskets and an olive-crushing mill).
At the hardware store you'll find shovels and spades in several grades, ranging from flimsy "economy" tools to industrial-grade, husky versions; the middle ground is best for most home gardeners. Most homeowner-grade shovels and spades employ hollow-back construction. "Construction-grade" tools are usually solid shank. These terms refer to how the manufacturer forms the socket to join the blade and handle.
Solid-shank tools have both blade and socket forged from a single bar of metal. Hollow-back shovels are usually stamped from a metal sheet that's rolled over to create a depression called a frog. Some shovels have a plate welded over the frog to increase strength and keep the wooden handle drier and less prone to decay.
The solid-shank construction is stronger at precisely the point where the greatest forces are exerted on the tool--the fulcrum. If you're working very heavy soil or prying lots of roots and stones, solid shank is the way to go. Hollow-back construction, however, produces a lighter, less fatiguing and less expensive tool.
Handles come in two flavors--long and short. Short handles are usually topped with a long handles are sometimes shaped to provide easy gripping surfaces. The traditional handle material is northern hardwood--usually ash, sometimes hickory. Both combine great strength with a reasonable flexibility. Some manufacturers have also introduced handles of fiberglass and epoxy, sometimes reinforced with carbon fibers. They're a little lighter than wood, less likely to break under extreme loads and resistant to water and decay.
The angle at which blade and handle meet is the lift. Spades typically have very little lift, thus maximizing the force you exert on the back of the blade with your foot. The standard lift in the North American garden shovel is about 37 degrees--a concession to the tossing (as opposed to digging) function of the tool.