The Leek variety Giant Musselburgh provides some great benefits for reducing the length of time and amount of energy involved with the seedling stage of leek production. Musselburgh leeks naturally reproduce by producing small bulbs, or plant clones surrounding the stalk of the mature leek, around the same time as the leek produces seeds on its flower stalk.
The research of comparing leek clones to plants started from seeds demonstrated that clones produce a heartier succession crop of leeks, especially with the thicker bulbs that form underground on older leeks. The thinner clones with more leaf development were slower to advance their growth after transplanting.
The examination of coppicing as an option to allow multiple cropping, while clones develop, proved that this is a possibility for farmers, but that the crop of clones was diminished, somewhat following the coppicing process. It may be that this reduction, in size and quality in coppiced clones, was due to lack of shade after the leeks were coppiced. In that case, a thicker companion crop that effectively shades the bed might have improved the number and quality of clones produced. I tried peppers as a companion crop. Choosing to try melons or cucumbers might have been a better choice, providing better shade for the coppiced leeks.
Elixir Farm is a small scale organic farm, specializing in mushroom production, grass fed beef, and high quality organic vegetable production. The farm consists of 330 acres along the Bryant Creek in Ozark County in southern Missouri.
Vegetables such as Leeks, garlic, potatoes, lettuce and other greens are grown outdoors in terraced beds and in 2 hoop houses during winter months. Cover cropping and crop rotation are important components of the farming system at Elixir Farm. Cattle are managed with rotational grazing. Crops and beef are sold primarily at farmer’s markets, and some wholesale, in St. Louis.
The farm has been organic since the 70’s and certified organic for over 30 years. Sustainable practices such as cover cropping and drip irrigation, floating row cover for frost protection, and planting on terraces (for water conservation) have been used for over 20 years. Grid tied solar power was set up here in 2007. Frost proof tanks, portable electric fence, spring fed cattle watering, and management intensive grazing were implemented in the last 7 years. Mushroom production using single tree selection for timber stand improvement has been in practice for the last 5 years.
The research in this project intended to make several comparisons related to leek production and leek clone production. I intended to assess replanted leek clones, compared with seedlings started from seeds, evaluating them for their rate of maturation and considering the amount of time and energy required for each production method.
I also intended to assess different methods of producing leek clones. Clones produced the usual way, from the base of overly mature leeks that have “bolted” and gone to seed, were compared with clones from leeks that were “coppiced”. Coppiced leeks are ones that are completely cut off at about a half inch from the soil surface. In the case of coppicing, clones continue to grow out of the leek root ball that remains in the soil.
The final objective was to establish an understanding of how many successions of leek crops are possible in the warmer seasons of the year.
Comparisons of clones and seedlings were undertaken both outdoors and in the winter hoop house. Outside, clones and seedlings at 6 weeks old were planted on opposite sides of the same terraced rows. In the greenhouse, clones were transplanted into 6 raised beds (beds are 10′ X 3′) and seedlings were transplanted into 4 beds in the same hoop house. In these comparisons, the harvested yield would be evaluated for size and quantity.
Comparisons of coppiced leeks and leeks gone to seed were conducted in the hoop house only. Six beds were coppiced and another 6 beds were left to grow their seed stalks to maturity. At the time of removing clones from these beds, I counted and evaluated the clones produced.
Over the 2 years of the research, leek crops were planted indoors and outside at different times and with different levels of success. I evaluated harvests and the labor and time investment in an effort to discover what are some of the best times of year to begin leek crops.
Leek clones reduced the time involved in leek production by at least 6 weeks. Seedling comparisons in the outdoor and greenhouse settings demonstrated no noticeable superiority to the plants started from transplanted clones. The seedlings eventually reached a similar size to the leeks started from clones, but they were slower to grow. In late spring, the delay in growth can lead to a loss of quality, as heat and dry conditions can set in and start “bolting”.
On average, leeks allowed to mature fully generated 8 or 9 useable clones from each matured plant. The clones averaged between 3 and 4 on coppiced leeks.
In the beds where leeks were coppiced, pepper plants were grown during the summer months. The beds were only 3 feet wide, so each bed had only 5 or 6 pepper plants. There was an added challenge in adding the pepper plants to the beds without disturbing many of the coppiced leeks. The usual practice of turning the soil was not possible, and may have contributed to the modest growth of both the pepper plants and the clones in this condition.
Impact of Results/Outcomes
Through use of clones, I extended the season well beyond the usual winter leeks that I have grown in the past. The winter leeks are slow growing and appear to remain nearly dormant for several weeks, but the slow growth and cool temperatures generate great flavor and nice size. By utilizing the clones of the winter leeks, a new transplanted crop was successfully managed both years, planted out in late April/ early May and an addition crop was started in late summer, to mixed success.
The summer crops are not as crisp and can be softer in a way that detracts from their quality and flavor, but most of the harvested leeks were market grade, and were profitable and worthwhile to grow.
The fall crop would need to be planted out in early august and watered heavily to endure the summer heat stress. Waiting until the weather cools would mean that they would not be full size by Thanksgiving, which is about the last moment for the leeks to take on any fall growth.
The winter crop can be planted outside at roughly the same time as the indoor crop in the hoophouse. I planted in late September and the plants grew very little before the winter weather arrived. the plants in the hoophouse maintained their condition and then took on size rapidly in early March. The outdoor leeks were subjected to several days of subzero temperatures, and their outer leaves were damaged, but in March the damage was hardly visible, as they grew new leaf material and started to increase size at the base. The result of these two crops, one indoor and one out, is basically 2 different harvest dates. The hoophouse crop is ready in April and the leeks outdoors are ready the month after. For a market gardener, this is a very useful and promising strategy.
Educational & Outreach Activities
I generated a presentation to share the results of this project. I showed the slide show and described what I learned at 5 events in the counties of Ozark, Douglas, and Howell in southern Missouri. 118 farmers have particpated in these programs so far. I am intending to participate in the state-wide organic conference during their next meeting, and present at the local extension’s horticulture program which is still being planned. After these presentations, I will have shared my project with over 250 farmers.
I will continue to refine planting dates for leek succession crops, especially regarding the fall crop, and begining it soon enough that it has time to reach full size before winter.
Another aspect which needs further attention is the combination of leek coppicing with other companion crops. I think especially in the summer that a crop with heavy foliage might increase the number of clones produced. I think shade would allow the clones to develop without additional stress of heat, lack of moisture, and soil hardpan.