Urban agriculture is a rapidly expanding movement; a lot of people are wondering how to get started and above all how to garden without the luxury of a nice patch of ready-for-planting earth. Lasagna growing has proved to be a modern and eco-friendly solution for growing things in a poor, compact, grass-covered soil – or even on asphalt. All that without hurting your back.
The origin of lasagna 2.0
It was in the 13th century, well before the arrival of tomato sauce in Italy, that lasagna gained in popularity. Seven centuries later, in the 1990s, the American Patricia Lanza noticed during a hike in the woods that the top layers of soil were made up of alternating leaves, woody debris and dead plants – a bit like a lasagna!
She got the idea of re-creating that model in her backyard to deal with the problem of her stony clay soil and to create a garden. So she put down successive layers of her grass clippings, horse manure and her kitchen waste. The first lasagna garden was born.
The initial stage consists in covering soil with cardboard or a few thicknesses of newspaper in order to smother the weeds. Next you set down 5-centimeter layers of brown waste and green waste, dampening each layer. You finish with a good layer of potting soil. If it’s the right season, you can plant immediately. Otherwise you have to wait until the next spring. That’s all there is to it!
Some examples of brown waste (high in carbon):
- Small branches;
- Brown paper, newspaper or cardboard;
- Dead leaves;
- Egg cartons;
- Wood chips.
Some examples of green residue (high in nitrogen):
- Grass clippings;
- Fruit and vegetable peels;
- Coffee grounds;
- Bread, rice and cereals.
What’s the best recipe?
Mummy’s, of course! Although different recipes are suggested on “the internets,” the best in my opinion is still the one that allows you to put your own locally produced organic waste to good use.
Whereas cooking a catchall lasagna is an opportunity to use up your stale vegetables, your garden lasagna is an opportunity to recycle a big part of your green waste. Even wood waste like branches and tough stems can be incorporated into the bottom layers. The thickness of the layers can vary, but my suggestion is to make the layers thicker underneath and thinner on top. The important thing is to alternate carbon sources (the brown) and nitrogen sources (the green) and to finish with a nice thick layer (10 centimeters) of potting soil or compost.
And newspaper ink in all this?
Toxicity standards for newspaper inks have evolved considerably in Canada over the past thirty years. Nevertheless there’s still some confusion as to the safety of the pigments and other components used. A similar debate exists around the glue used in the manufacture of cardboard boxes. Opinion is divided, so it’s your decision.
Personally I prefer cardboard without ink or glue, and I use newspapers now and then. That said, dead leaves and straw are still two interesting options.
For more information:
- The height of your lasagna can range from 30 to 70 centimeters.
- It’s normal for it to progressively sink.
- Feel free to add earthworms.
- This technique also applies to growing in pots or tubs.
- It’s not ideal for seedlings (e.g., carrots, radishes) or for perennials.
- It’s preferable to flatten your lasagna rather than building it up into a dome.
- Vary the residue sources and make sure to tear them into shreds.
- The next spring, add another layer of compost.
- After a few years, the whole thing should have completely decomposed.