Keyhole gardens: Drought-friendly twist on raised beds

They don’t need fertilizer, use 80 percent less water than the normal backyard patch, tolerate hot climates and are easier to tend because they’re at waist level. No bending or kneeling required.

Keyhole gardening was pioneered in Africa and became popular there again recently through initiatives by humanitarian aid groups.

A keyhole garden’s primary asset is drought tolerance, although it also works in temperate climates, said Eddie DeJong, co-founder and head of business development and design for Vita Gardens in Sarnia, Ontario. The company makes keyhole garden kits.

The gardens get their nourishment from compost and water poured down an open-ended tube in the middle of the garden bed.

“The central composting basket is the key to making this an effective gardening solution,” he said.

“After the garden has been established, it should be watered primarily through the compost basket and less and less around the bed itself,” DeJong said. “This trains the vegetables to grow deep roots down to where the moisture and the nutrients are.

“Furthermore, if the garden is layered as intended, local yard waste like grass clippings, palm fronds and other materials are converted into rich soil, making the entire bed a composting nutrient factory.”

Keyhole gardens are cheap and simple to assemble. African children often build them in schoolyards or for their families.

Structural components include native and recycled materials as straw bales or bricks. “We don’t use waste lumber because it rots down too easily,” said Rose Marie Nichols McGee, president and owner of Nichols Garden Nursery in Albany, Oregon. “Tractor tires are an uncertainty because they may contain toxins.”

Some commercial kits offer a more tailored look for use on patios and decks.

DeJong said his company is working on lighter, more compact sizes for keyhole gardens, and “aluminum and composites for a modern urban look.”

Keyhole gardens have proven to be more productive for McGee than regular raised beds.

“This is particularly true of tomatoes, peppers, beets and carrots,” she said. “Some of this is probably due to the hundreds of worms the keyhole garden promotes, and an abundance of worm castings is one of the best fertilizers and soil conditioners.”