Small fruits and berries, especially organically grown, are a big draw at farmers’ markets and CSA’s. However, many of these crops can have significant start up costs, may take many years to bear profitably, and can be challenging to grow, notably for new farmers who are trying to master the many components of a mixed vegetable operation. I believe litchi tomato, Solanum< sisymbriifolium, has potential as an ‘easy-entry’ small fruit for vegetable growers in the Northeast. We grew several plants on our farm last year, and CSA members who sampled the fruit universally liked them, comparing their flavor to rose hips, cherries or raspberries, and said they’d be excited to have litchi tomato as an offering in our CSA. Preliminary research into how to best grow the plants, data on yields and harvest labor, and an assessment of weed risk are important first steps in determining the viability of litchi tomato as a specialty crop. Novel fruit offerings could help boost farmers’ market sales and build customer loyalty, as well as make CSA offerings more robust and attractive to new members. Assessing weed risk is important in protecting natural resources (surrounding native ecosystems), as well as trying to ensure that the plant doesn’t become a management problem on farms.
The goal of this project is to make a preliminary examination of the feasibility of litchi tomato as a novel niche crop. There are two primary goals. (I want to figure out how to best grow this thing and make sure it won’t take over the world!) I will conduct greenhouse germination trials to better understand when to start seeds for maximum yields and also test if treated seeds germinate better. Seedlings will be planted out in the field in a randomized block design, and I will collect growth and phenological data. Yield and harvest data will be collected. To assess weed risk, small plots will be sown with litchi tomato fruits in the fall of the first year to mimic natural dispersal of the fruits. The plots will be monitored over the next year for germination, flowering, and fruit set and maturation.
Our farm is a small mixed vegetable and pastured poultry operation on six acres, marketed through a ~50 member CSA, a farmers’ market, and a local food cooperative. We raise about 400 broiler chickens and a small number of turkeys annually. While Cobblestone Farm has been a full time business for me since 2015, my husband and I have been growing for friends and family for more than a decade. Gross sales for 2016 as of November 16, 2016 are approximately $24,500. Aside from farming experience, I also have a B.S. in Ecology and Evolutionary Biology. I have conducted my own (small and unpublished) field experiments and have collected data for larger invasive species studies.
Small fruits are a missing component of our CSA offerings, and local farmers’ markets are often undersupplied in fruit. Our customers prefer organic production, yet we don’t live in a particularly high income area, so profitability of small fruits can be challenging, given the high labor costs and perishable nature of small fruits. I am excited about the possibility of offering litchi tomato as a new crop to our CSA members and market customers. We grew a small number of plants this year, and members who tried the fruits enjoyed them, describing the flavor as floral, tropical, and reminiscent of raspberries. Having small fruits to offer would make our CSA more robust, as well as be a nice draw for customers at farmers’ market. Litchi tomato has potential because of low start-up costs, ability to harvest in the first year, and long harvest window. Additionally, fruit seems to hold well at room temperature.
Rob Durgy of the Connecticut Agricultural Experiment Station will be my technical advisor. Rob will assist with general experimental design, insect identification, review of statistical analysis, and coordinating outreach efforts.
Very little information is available for growing litchi tomato for fruit, and most of it is anecdotal. I have not been able to find any technical information. Articles in gardening magazines describe litchi tomato as prolific and easy to grow, yet online comments for seed companies and gardening blogs report varying success with germination and yields. One goal of this study is to establish germination protocols that maximize yields, which is a crucial first step in determining how litchi tomato could become a viable crop.
Regarding the potential weediness of litchi tomato, weed risk assessment modeling was conducted by USDA-APHIS in response to potato growers interest in S. sisymbriifolium as a catch crop for potato cyst nematodes. The modeling categorized litchi tomato as high risk, in part due to the reported ease by which it spreads into disturbed habitat, that it is already established in 17 states, and that several other members of the genus are problematic weeds in the US. Litchi tomato is also a reported weed of rangeland in South Africa and Australia. However, while the plant is reported from our neighboring states of New York and Massachusetts (no records for CT), it is very uncommon. It is reported from four counties in New York, and three counties in Massachusetts. The most recent record found for Massachusetts was from 1955. Given that litchi tomato has occurred in the Northeast for decades yet not become problematic, one could conclude that it’s weed risk potential for our region is low. Additionally, litchi tomato is being used on a commercial scale in the Netherlands and England to control potato cyst nematodes, and I have not found reports of it becoming a problematic weed. (It is possible, however, that the plants get turned into the soil before producing viable seeds.) It is also noteworthy that litchi tomato is native to Brazil, so while it can be a persistent weed in some areas, our winters are too cold for the vegetative plant to survive beyond one year. Yet given the APHIS modeling, and that the plants are heavily armored with spines, making for a very unpleasant weed, a systematic field study of potential weediness would be prudent before growing litchi tomato on a larger scale.
3/22/17 Litchi tomato seeds were treated with HCl (strength?), 100 seeds each at 2, 4, and 6hrs, then rinsed under running water for 1 minute. Seeds were dried on paper plates.
3/24/17 Seeds were planted in 2″ soil blocks, 2 seeds per block, 50 blocks per tray. (First planting) There were four trays in total, one planted with untreated seed, the others with the 2, 4, and 6 hr treatments.
Plants were grown on heat mats set at 75 degrees, in a greenhouse with night time low set at 54 degrees.
Note: seeds were harvested from our farm the previous season, fermented as tomato seeds are, then rinsed and dried.
4/1/17 First signs of germination were recorded after 7 days. 66 seeds germinated from the untreated lot, 18 from the 2 hr treatment. Zero from the 4 or 6 hr treatments.
4/3/17 Germination: 75% from untreated lot, 28% from 2 hr treatment. Zero from 4 or 6 hr.
4/7/17 Germination: 77% untreated, 49% 2 hr, 6% 4hr, 0 for the 6 hr treatment.
4/18/17 Final germination count at 26 days after planting: 77% for untreated seeds, 51% for seeds soaked 2 hrs, 27% for the 4 hr treatment, and 0% for the 6 hr treatment.
Unheated tray thinned to 1 plant/block.
Two new trays were started with 100 seeds per tray, 2 seeds/block. (Second planting) One tray was kept on a heat mat set at 80 degrees, the other was on an unheated bench. Greenhouse minimum temp was still at 54 degrees.
4/26/17 Germination for second planting was first noted after seven days. 26 seeds germinated in the heated tray, 0 in the unheated tray.
25 plants from the 1st planting were transplanted into (dimension? – tomato) pots. 20 for field planting, 5 to examine for adventitious roots. Ten plants were measured, from top surface of the soil block to the highest leaf tip.
days after planting does not include planting day
reports of bad germ may be from unfermented seed
source of protocol for soaking seeds
Height of plants from 1st planting at 33 days from planting: 55, 60, 51, 88, 85, 58, 56, 75, 71, 62cm. Average height was 66.1cm.
12 days after sowing, germination rates for the second planting were 68% for the unheated tray and 76% for the heated tray. All plants in the heated tray were just cotyledons, where most plants in the heated tray had developed their second true leaf.