Fordhook Lima Bean Production

Emmalea Ernest, Extension Associate – Vegetable Crops; emmalea@udel.edu and Gordon Johnson, Extension Vegetable & Fruit Specialist; gcjohn@udel.edu

The original Fordhook lima bean was collected by Harry Fish in 1904 in Carpinteria, California. Carpinteria is a coastal town located just north of the Oxnard Plain. The Oxnard Plain, being surrounded by mountains on three sides and the Pacific Ocean on the fourth, enjoys a moderated climate with highs between 65 and 75°F and lows from 45 and 60°F year round. The Oxnard Plain continues to be the premier location for Fordhook lima bean production and yields can be upwards of 4 T/A.

Fordhook limas were introduced to the US at large by W. Atlee Burpee & Co. in the early 1900s and their popularity soon led to production for processing on the East Coast, particularly in New Jersey and Delaware. Yields of Fordhooks have historically been lower on the East Coast, probably because they are not as well adapted to the climate, and from early on, were plagued by downy mildew caused by Phytophthora phaseoli. Renewed interest in Fordhook production in Delaware has prompted us to produce this summary of recommended practices for Fordhook production, based on research done in the region.

The two Fordhook varieties that are available at the present time are Concentrated Fordhook (CFH) and Fordhook 242 (FH 242). Both are selections from the original Fordhook variety and have white seed. The USDA lima breeding program released a number of green seeded varieties with downy mildew resistance in the 1970s and 80s (F 1072, F 169, F 90-1), however none of these varieties are commercially available any more.

Results from Fordhook yield trials conducted over four decades at the UD Research and Education Center in Georgetown, DE are summarized in Table 1. This data represents 22 separate trials of Fordhook varieties. The average yield over all of the trials is 2521 lbs shelled beans/A. Because some trials included very poorly performing experimental varieties, this average yield is somewhat lower that what would be expected with commercial varieties. The average yield for FH 242 in the trials (7 years) was 3703 lbs/A and the average yield for CFH in the trials (3 years) was 2908 lbs/A.

Table 1. Summary of Fordhook Lima Bean Variety Trial Results 1972-2010 Including Planting Date, Days to Harvest, Yield of Shelled Beans in Lbs/A, Number of Lines Tested and Description of Trial Entries.

One oft-aired complaint about Fordhook lima beans is that they yield inconsistently in Delaware. The range of yields reported in the above table, 1079-4177 lbs/A, would seem to attest to this. There are however, some management practices that can be used to reduce the potential for yield variability.

Sites and Soils
Historically, much of the Fordhook lima bean production in the region has been done close to the coast (Delaware Bay, Atlantic Ocean) because of the moderating effect of the water on temperature. Inland sites will have greater temperature fluctuations and as a result more variable yields. Coastal sites also have heavy dews, fogs, and higher humidity that will improve pod set. However, this can create an environment favorable for downy mildew. Fordhooks will grow well on a range of soil types from loamy sands to silt loams but require good drainage. Higher moisture holding capacity soils such as silt loams or those with high organic matter content will provide for better performance.

Planting Date
Fordhook lima beans are more heat sensitive than baby limas. They should be planted at the end of June or very beginning of July so that they are not exposed to high temperatures during flowering. They can also not be planted as late in the season as baby limas, because they require, on average, 93 days to harvest, versus the 75-85 days required by baby limas. Based on the trials summarized above, the average yield for trials planted before June 20 was 2096 lbs/A, while the average yield of those planted after June 20 was 3050 lbs/A – a difference of almost 1000 lbs. Risk of split sets or delayed sets is higher with early plantings. This narrow ideal planting window often leads to a narrow harvest window which can affect plant scheduling with high volumes in a short period of time.

Stand Establishment
Fordhook lima bean seeds are large and rough handling before or during planting can cause reduced viability and stand loss. Set up planters to limit bounce in seed drop and plant at slower speeds. Ensure good soil to seed contact with proper press wheel adjustment. Plant at a 1 ½ inch depth. Soil crusting during emergence can also have a devastating effect if the cotyledons are trapped in the soil and the hypocotyl breaks in half. The resulting “headless” seedlings will not recover. Similarly, if only one of the two cotyledons emerges intact, the plant will be stunted. The large seeds are also susceptible to attack by insects and pathogens. Use high quality, treated seed and handle it gently. Make sure soil conditions are optimal for germination and emergence in terms of moisture (temperature should not be an issue in the ideal planting window) so that seedlings emerge quickly and are not exposed to excessive insect and disease pressure. Be prepared to irrigate to maximize germination and to limit the effect of crusting. Lima beans compensate well for stand loss, however, the resulting larger plants will be slower to mature and are more difficult to harvest mechanically.

Irrigation
Fordhook lima beans should not be grown without irrigation. Adequate irrigation can mitigate stress induced by heat. Peak water usage will be from flowering through early pod set where plants will be using from 0.25 to 0.33 inches of water a day.

Fertility
Fertilizing Fordhook lima beans will be similar to baby lima beans. However, because of the longer season, the higher Nitrogen (N) rate should be used, especially on sandier soils. Apply 40 lbs of N preplant or at planting and follow with a sidedressing at final cultivation of an additional 40 lbs of N. This will be 80 lbs of total N. When following peas, 20-30 lbs of total N will be adequate. Phosphorus (P) and potassium (K) requirements are the same as for baby lima beans. See the Delaware Commercial Vegetable Production Recommendations for specific P and K recommendations according to soil test levels.

Diseases and Insects
Neither FH 242 nor CFH have resistance to downy mildew. Late June and early July planting dates mean that Fordhooks will be setting pods during the cooler part of the season when downy mildew and white mold are most problematic. Effective controls are available for both of these diseases in lima bean and should be employed if necessary.

Also be aware that Fordhook limas maturing in the fall will also have more exposure to worm pests that attack pods. Stinkbugs and Lygus bugs are another concern for pod and seed damage. The large pods are very attractive to these pests at a young stage.

See the Delaware Commercial Vegetable Production Recommendations for specific guidance on lima bean disease and insect management.

Harvest
Because of the large seed, pod and seed loss at harvest will have a large effect on crop recovery and yield. All efforts should be made to reduce harvest losses. This includes making sure fields are as level as possible, there is limited ridging from cultivation, and harvesters are operated to maximize recovery.