Vetiver Grass and its use as a garden mulch in Belize

From: Don Thompson, P.O. Box 104, Belmopan, Belize, Central America
Organization: Sibun Watershed Association <swa@btl.net>
Farm Location: Caves Branch, mile 43 Hummingbird Highway, south of Belmopan, Belize
Purpose of this Report: To describe how I am using vetiver grass as garden mulch
Objective: Book Offer, Vetiver Grass: An Essential Grass for Planet Earth

Introduction

First, here is an explanation of how I got started using vetiver. I originally learned about vetiver by reading about it in the Agroforester, October 1999 «Overstory» edition #45 called Vegetative Erosion Barriers. I looked up the vetiver web site and from there received an information package from Joan Miller, who at that time, was stationed in Costa Rica. Soon I decided to try planting some vetiver myself My first planting of vetiver was mid January 2000 using a few roots dug up from a V2 acre plot of vetiver planted at Central Farm (the agricultural information and research station for Belize) sometime between 1991 and 1993. Of this original planting of about 10 plants, 7 plants remain to this day, the other 3 having been dug up for re-planting in late 2001. After this first planting, I acquired two polybags of vetiver tillers in May 2000 from Belize Sugar Industries, and from this material I started a nursery to aggressively produce more plants for the tillers. This nursery was established June 2000 and was left undisturbed until June of 2001. Then these one-year-old plants were dug up and from this, vetiver tillers were planted extensively throughout my entire garden, occupying about 80% of the available garden space. Also began to establish vetiver as the sole plant material for the boundary (fence line) of a 1-1/4 acre yard of the citrus farm where I am situated. As a result, vetiver is now being established to form the foundation for my entire gardening program.

Planting System

For the first year and half, I planted solid clumps of 5 to 8 roughly prepared, tightly packed tillers into planting holes spaced about 60 cm apart. Now I prepare planting material by separating tillers into as many individual pieces as possible, washing off all soil and removing dead pieces, and finally trimming the roots and tops. I now plant the individual tillers in a trench that runs for whatever length and direction that is required. Where conditions permit, I dig the soil to only one side of the trench. Then sprinkle a small amount of slow release 17-17-17 fertilizer into the bottom of the trench. Tillers are placed in the in the trench close together 3 to 6 cm apart, not vertical, but lying on an angle against the side of the trench, with the tops pointed away from the side where the soil was not piled up. After the trench is lined with tillers, I simply take a rake and pull the piled up soil over onto the roots of the tillers leaving a small point of each tiller poking through the soil. This method I find is much faster than trying to hold each tiller in a vertical position. Very little of the plant is exposed to the open air which helps to protect the tiller from drying out in the hot sun. Initially the grass grows out on an angle but after a month has passed, the blades begin to curve up to the normal vertical. After two months there is little evidence that the tillers were planted on an angle. Planting time in Belize is between the end of May to early January. Planting after January is risky due to the fact that dry season will soon start and the plants may experience stress due to lack of moisture. The Belize dry season normally extends from February to mid May with April sometimes having no rain at all. During the dry season I do not cut vetiver grass but leave it standing to act as a windbreak. The evaporation rate during April and May is very high due to the strong afternoon easterly winds.

Mulching System

Beginning late September 2002, mature vetiver grass plants have been systematically cut for mulching material. These mature plants have grown to a height of about 170 cm and have sent out flower stalks that droop over. For cutting the grass I mostly use pruning loppers, of the type that would normally be used for cutting off small tree branches. I cut the grass right down fairly close to the base of the plant leaving a stump with stem lengths of only 6 to 12 cm. After the stump has re-grown for a few weeks I then drench the re-growth with a liquid fertilizer containing micronutrients. By doing this I figure 1 can convert inexpensive chemical fertilizer into high quality organic fertilizer once the grass is cut for mulch. Beginning back in 1997, I constructed the garden as a raised bed gardening system. The construction of the raised beds was time consuming and labor intensive. In the dry season the beds would dry out rock hard and then when the rainy season began, the beds would rapidly become covered in weeds, which were difficult to eliminate. During this period, I used wood shavings as mulch between the raised beds. Now, I have abandoned the raised bed method and have switched to a vetiver grass mulch bed system on level ground with little or no digging. The rows of vetiver are spaced about 280 cm apart and the area between the rows is covered with vetiver grass mulch. Over time the grass mulch should break down forming a bed of rich organic matter. The mulched soil between the rows of vetiver is already improving with respect to drainage, moisture-holding capacity, weed suppression, and in the fertility. Further, the rows of vetiver will function as an effective windbreak, especially tempering the hot, drying winds that blow during the dry season. In conclusion, the use of vetiver grass as applied to my gardening project, is having a positive impact on the entire ecology of the garden area. Previously, I experimented with all sorts of different gardening techniques but this vetiver mulch system is the only one that is showing clear evidence that a continuous improvement is taking place.


Don Thompson, e-mail: vetiverbelize@hotmail.com