Several different types of beans (Phaseolus spp.) make good crops for a home garden, including the Lima bean (Phaseolus lunatus). This type is usually grown for its immature to partially mature seeds, not for its green pods. Sometimes also called butter beans or Fordhooks -- Fordhooks are extra-large beans -- Lima beans are warm-season plants grown as annuals in all parts of the United States. They need a warm growing season, lots of sun and just a bit of extra care to produce a heavy crop of flavorful beans.
Step 1: Pick the Right Time
For best results, don't start Lima beans too early; the seeds need warm soil that's at least 65 degrees Fahrenheit to germinate. This is usually about three or four weeks after your area's last frost, if winters have sub-freezing temperatures where you live. If spring tends to be long and cool in your area, you can help warm the soil before planting seeds by laying black plastic sheeting over the planting area. Secure the plastic into the ground with wire earth staples pushed through its edges and plant seeds after a few sunny days have warmed the soil, cutting a small hole in the plastic for each seed.
Step 2: Choose Type and Variety
Lima bean plants have bright green, pointed-oval leaves and stiff stems. Their small flowers are white or yellow, and pods are long and flat when fully formed; pods grow to 3 to 8 inches long, depending on the cultivar. The plants come in two types, either bush beans which grow as upright plants, or vining types -- called pole beans -- which need support.
- Bush Lima bean varieties include Jackson Wonder, 68 days to harvest; Fordhook 242, 65 days to harvest; and Burpee's Bush, 75 days to harvest.
- Pole types include Burpee's Best Pole, 92 days to harvest; and Big Mama, 80 days to harvest.
If space is scarce or you find it difficult to bend over when harvesting, choose a pole Lima bean variety.
Step 3: Plant Seeds
Choose a planting site that's in full sun -- at least 8 hours daily -- and has well-drained soil. If your soil is rich in clay, mix about 2 inches of coarse sand into the top 6 inches before planting to improve drainage. To help ensure healthy plants, raise your soil's fertility before planting by adding 2 inches of compost to the area, mixing it into the top 4 to 6 inches of soil.
Plant any variety of Lima bean seed about 1 1/2 to 2 inches deep, covering each seed with lightly tamped soil or with sand or mulch to prevent soil crusting, which can slow emergence of seedlings.
For bush types, space seeds 3 to 6 inches apart in rows that are about 3 feet apart. Plant pole varieties about 6 to 10 inches apart in rows that are 3 feet apart, or construct small hills with soil, planting five or six seeds per hill, with hills about 40 inches apart.
For any type of Lima bean, it's best to allow at least 6 inches between seedlings, so the plants have room to spread as they grow. If seedlings are spaced closer than 6 inches once they emerge, do some thinning by removing weaker plants. Don't disturb nearby roots by pulling them out. Instead, use sharp shears to cut the weak plants off at the soil level, cleaning your blades between cuts by wiping them in rubbing alcohol to avoid spreading plant diseases.
For pole Lima varieties, set supports -- trellises, fencing or tripod-poles -- that are 6 to 8 feet tall firmly into the ground before planting, to avoid disturbing the plants' roots. The vines develop tendrils as they grow which attach naturally to the support.
Lima beans grow best when they receive even, regular moisture. For best results, provide extra water to the plants whenever the top inch of soil is dry to the touch. Avoid overhead watering, especially during flowering, because this can damage flowers or cause small pods to drop; use a soaker hose or drip irrigation instead.
These plants don't require fertilization and can be harmed by nitrogen-rich fertilizers. The compost provided at planting time provides enough nutrients throughout the season.
Keep weeds down by cultivating around the plants, but take care not to disturb the Lima beans' roots, which tend to be shallow. Adding 2 or 3 inches of straw or bark mulch under the plants also helps suppress weeds, while conserving soil moisture.
Start harvesting Lima beans when pods are flattened and firm and you can see swellings along the pod that indicate the presence of beans. For smaller, more tender beans, harvest when the swellings are modest-sized and the pod is still supple and green. For large, fully mature Lima beans, wait until the pod starts to dry a bit and swellings become large.
To extend flowering and Lima bean production, pick medium-sized, plump pods every few days.