Growing Great Garlic (cont)
By: Robert Kourik
Garlic Growing Know-How
There are three problems when growing garlic: drainage, gophers, and onion root maggots. Though the plants love regular irrigation, they don't like heavy or waterlogged soil. In Aaron's experience, the roots need 16 to 24 inches of well-drained soil. After rain or irrigation, if water is visible when you stick your finger in the soil, the soil is too wet, and the garlic will rot. Aaron's farm has few drainage problems, but his land, like most gardens in his area, teems with ravenous gophers who seem to crave garlic as avidly as any gourmand.
Onion root maggots can also be a problem. These maggots of tiny flies lay eggs in soil around developing cloves. The maggots then find the garlic and tunnel inside, spoiling it. Onion maggots thrive in alkaline soil.
Aaron's solution to all three problems is to grow garlic in raised beds. He built 60 raised beds, each one about 4 feet wide and 10 feet long and spacious enough for 130 to 180 garlic plants, depending on the variety.
The rough-sawn 2-by-12 redwood boards he uses are unwieldy, so it's best to build the boxes in the garden, close to the desired site. Here's how:
On level ground, butt the boards to form a rectangle with the 4-foot pieces across the ends of the 10-foot ones. Join each corner with four 16d (16-penny) hot-dipped galvanized box nails. (Pre-drilling nail holes is advised if you're using wood prone to splitting.) If redwood is not an option where you live, use similarly rot-resistant eastern or western red cedar, inexpensive hemlock, or consider the ersatz wood planks made of recycled plastic. To foil gophers (which are less of a problem in the northeastern United States), Aaron stretches 4-foot-wide 1/2-inch-mesh aviary wire across the bottom of each box, then staples it in place.
Next, fill each box with a fertile, fast-draining soil mix. Aaron's usual mixture, called Spring Garden Mix, blends topsoil with well-rotted horse or cow manure or compost, sand, and finely shredded bark. Check with your local garden center for a good source of bulk soil mix and ask for a blend similar to the one Aaron uses.
Before buying a soil mix, Aaron recommends checking with other buyers, if possible, about the reputation of the supplier's soil mix, in particular regarding freedom from weed seeds. Also check to be sure the soil mix is slightly acidic, pH 6 to 7. Soils that are alkaline and have pH 7 and above are more favorable to onion root maggots.
Because the fall season in his area can be dry until November and there is little rain after mid-April, Aaron must irrigate his crop so that it will produce full-sized heads. He finds that drip irrigation is the most efficient way to water. For each 4-foot-wide box, Aaron uses four 10-foot lines of drip-irrigation tubing equally spaced across the box's width. He prefers in-line emitter tubing with 1/2-gallon per hour (gph) emitters preinserted inside the tubing every 12 inches. The four lines of tubing are linked together at both ends of the box with more in-line tubing, and seven boxes can be connected together via solid pipe (3/4-inch solid, schedule 40 PVC irrigation pipe) as one watering unit. During the warmer parts of late spring, Aaron will irrigate for a mere 5 to 10 minutes every morning when there's no rain, or about 2 to 4 gallons (48 emitters at 1/2 gph, or a total of 24 gph) per box.