Grow your own fertiliser and mulch
Our soil here in Derby needs lots of organic matter to loosen up the pindan and provide nutrients for growing vegetables. The easiest way to bolster our soil is to cultivate fast-growing plants that can be chopped and dropped onto the garden beds, without paying for costly inputs such as mulch or hay or compost. The wet season is the ideal time to cultivate those plants that are used for this purpose.
Layer 1 – Leaves from Gliricidia Sepium If you have plenty of green legume material it just needs to be spread thickly over the bed, if there are lots of weeds then put cardboard down first, making sure that all layers are thoroughly wet
The legume family of plants is very useful for improving the soil, primarily because the roots and leaves add nitrogen to the soil. Within this family are little annual plants such as peanuts and mung beans, tall trees such as Glyricidia Sepium (mother of Cocoa) Sesbania Grandiflora, Acacias and shrubby plants and vines such as pigeon and butterfly pea and many other varieties of climbing beans.
The peanuts and mung beans are useful as ground covers as well as providing a crop. Once harvested the remains of the plant is simply used as mulch or dug back into the garden bed.
Layer 2 Vetiver and lemon grass leaves spread over the legumes. If these long leaves are spread in the direction you intend sowing the veges they can be moved gently aside in rows so that seedlings can be planted in between and thus given protection. The vetiver grass clumps can be seen in the background with cardboard laid down on the pathway.
The leaves of Glyricidia and Sesbania and pigeon peas are very beneficial when preparing vege beds with the lasagna or layering method. With this process we can leave the weeds in place, just cover them with cardboard and wet down thoroughly then add a layer of the leaves from a nitrogen fixing tree or if you have moringa trees with lots of leaves they are also useful. The next layer can be single stem leaves such as lemongrass, vetiver or bamboo. These leaves are usually tougher than the legume foliage and take longer to breakdown, they contribute their own unique qualities to the soil such as silica in the bamboo. Not only does this method of layering add nutrients and bulk to the soil, they also increase water holding capacity and protect the soil from the fierce sun.
Lemon grass and vetiver can also provide insulation or structure to raised garden beds with the added benefits of constantly available mulch right where you need it throughout the season.
The key is to plant these supports now when there is hope of rain and speedy growth. Then when it comes time to plant out the vege beds you have supplies at your fingertips. The key plants are Lemongrass or vetiver grass, Gliricidia or Moringa trees and bamboo also the butterfly pea vine and mung beans and peanuts.