Lavender Intercropping and Soil Management
After our second year of this project we have completed much work but have also suffered a few set backs with cover crop germination. We were able to run a second trial of lavender plants in custom soil mixes, received several visitors to the farm interested in the trials, and had continued success with the establishment of Buffalo grass as one of our cover crop trials.
1. To research multiple soil mixtures for more precisely amending soil conditions in the immediate root zones of Lavender and documenting results. (Years 1-3)
In 2016, our farm transitioned to certified organic so we added two different certified organic soil mixtures to the project to compare with the leading soil mixture of the 2015 trial. We measured the growth, bud yield, and overall plant health of 2 inch lavender starts that were transplanted into 5 gallon pots containing three different mixtures. The results of these mixtures are listed below and will continued to be measured in 2017.
Soil #1 – 25% compost, 20% sand, 5% pumice, and 50% screened composted mulch (1in. or smaller).
Total Buds (32 plants) = 2 oz.
Average Height of Growth = 8.5 in.
Average Health = Best – many branches spread 80-90% of pot width
Soil #2 – 35% compost, 40% red cinder, 10 % pumice, and 15% pecan shell hulls
Total Buds (32 plants) = 1 oz.
Average Height of Growth = 6.25 in.
Average Health = Good – many branches spread 50-75% of pot width.
Soil #3 – 75% compost, 25% native sandy loam
Total Buds (32 plants) = .5 oz.
Average Height of Growth = 3.5 in.
Average Health = Poor – very little spread of 10-20% of pot width.
2. To research multiple different cover crops for surrounding soil to match water conditions of lavender and reduce field competition. (Years 1-3)
In 2015, we were able to successfully establish Buffalo grass which is still growing well. We attempted cold stratification of both the Purple Poppy Mallow and the Prairie Zinnias seed but they did not germinate in the field that year. In the Spring of 2016, we started to see some of the Purple Poppy Mallow grow in but only at a 5% coverage of the rows where it was seeded. None of the Praire Zinnias germinated so we decided to attempt to start these in a greenhouse in trays. They still did not germinate so we are concerned the seed source may have been damaged and will attempt to find a different source in 2017. If we still cannot get germination we will purchase plant starts and transplant a section of a row to see how it performs. The Purple Poppy Mallow germinated at over 95% in the greenhouse and will be attempted to be transplanted as plugs in the Spring of 2017. The Purple Poppy Mallow has a thick tap root and are expected to do well in dry conditions once established. It is still unknown how these plants might spread over time since they both proved to be difficult to start in the field from seed.
3. To provide site visits and publish results of this research and encourage the adoption of best practices to Lavender farmers in the Southwest region. (Year 3)
We had several visitors to the farm to see our progress. Several other lavender farmers visited to see particularly how the buffalo grass was working with the lavender. We plan to have many more visitors in 2017 and return visitors if we can get all three cover crops established. We feel that these side-by-side trials will increase interest in the overall project.
After the second year of this project there has been encouraging results as to which soil mixture is performing the best in pots with lavender. We also are also encouraged by the performance of the Buffalo grass within the lavender and plan to plant the remainder of the lavender field with it. It has greatly reduced weed pressure while providing erosion control.
Impacts and Contributions/Outcomes
We have successfully increased interest and discussion in soil and cover cropping in the immediate lavender growing community. Once the other cover crops are established we hope to expand further interest in these techniques to others interested in starting to grow lavender and those looking to improve their own fields. In 2017, we will explore the process of harvesting and cleaning the Buffalo grass seed as a potential source of income for otherwise fallow or weed competing crop alleys.