Polyculture is, obviously, the opposite of monoculture, but in permaculture (a lot of -cultures here) it means more than that. The best way to plant in polyculture is to follow the guidelines for a plant guild . A plant guild is how plants arrange themselves in nature so that each fulfills a niche. The variety of plants aren’t competing for the same nutrients and are delivering something other plants need; i.e. shade, nutrients, root exudates, leaf drop, soil in-roads via deep tap roots, etc.
When planting veggies here at Finch Frolic Garden I often mix up a handful of vegetable, herb and flower seeds that fulfill the plant guild guidelines and plant them all in one area. They come up in a mix of heights, colors, shapes and scents to fool bugs. The result is like a miniature forest.
However that sort of wild designed planting has its drawbacks. Harvesting is more time consuming (although more fun, like a treasure-hunt). Many people find peace in looking at rows of vegetables, and peace is valuable.
You can plant polyculture in rows as well. Just plant each row with a different member of the plant guild, and you’ll achieve a similar effect with insect confusion, and with nutrient conservation.
In this small, slightly sunken bed (we are in drylands so we plant concave to catch water), we planted rows of three kinds of potatoes, two kinds of shallots, a row each of bush beans, fava beans, parsnips, radish and carrots.
We covered the bed with a light mulch made from dried dwarf cattail stems. This sat lightly on the soil and yet allowed light and water penetration, giving the seedlings protection from birds and larger bugs.
The garden a couple months later. Because we had a warm and rainless February (usually our wettest month), our brassicas headed up rather than produced roots and only a few parsnips and carrots germinated. However our nitrogen-fixing favas and beans are great, our ‘mining’ potatoes are doing beautifully and the shallots are filling out well.
Every plant accumulates nutrition from the air and soil, and when that plant dies it delivers that nutrition to the topsoil. In the case of roots, when they die it is immediate hugelkultur. Without humans, plants drop leaves, fruit and seeds on the ground, where animals will nibble on them or haul them away but leave juice, shells and poo behind. When the plant dies, it dies in place and gives back to the topsoil. When we harvest from a plant we are removing that much nutrition from the soil. So when the plants are through producing, we cut the plants at the soil surface and leave the roots in the ground, and add the tops back to the soil. By burying kitchen scraps in vegetable beds you are adding back the sugars and other nutrients you’ve taken away with the harvest. It becomes a worm feast. Depending upon your climate and how warm your soil is, the scraps will take different lengths of time to decompose. Here in San Diego, a handful of food scraps buried in January is just about gone by February. No fertilizer needed!