How to Grow Lima Beans

Lima beans (Phaseolus lunatus), also known as butter beans or chad beans, grow in much the same way as green beans (Phaseolus vulgaris) do, though they tend to take a little longer to mature. Lima beans have the familiar compound leaves found on other beans: three (trifoliate) oval leaflets that are about 2 to 3 inches long. The plant's flowers are white or yellow and form loose clusters. The resulting pods are curved and flatter than those of common green beans.

Lima bean plants are started in the spring and have a relatively fast growth rate, taking around two to three months to mature depending on the variety. They must be fully cooked to be safe. Raw lima beans, along with the plant roots, are toxic to humans and animals.

How to Plant Lima Beans

When to Plant

Lima beans are a warm-season crop that should be planted in the spring after all danger of frost has passed. The soil should be at least 65 degrees Fahrenheit for seeds to germinate. This means you should wait roughly two weeks after your last frost to plant.

Selecting a Planting Site

The planting site should have loose soil and lots of sun. Raised bed or container growth is also an option. Don’t plant beans near members of the Allium family, as they can actually hinder root growth on the bean plants.

Spacing, Depth, and Support

Plant seeds roughly 1 inch deep and 2 to 4 inches apart. Thin seedlings to about 4 to 6 inches apart. Rows should be spaced 2 to 3 feet apart.  Seeds should emerge in 7 -18 days.

There are both bush and pole varieties of lima beans; the bush types will begin setting pods sooner. Bush types grow 2 to 3 feet tall and may need staking when they are covered in pods. Pole beans will need sturdy support, as the vines can easily grow 10 feet or more and become heavy with pods. Plant four to six seeds on each side of a trellis or teepee.

Lima Bean Plant Care

Light

You will need a spot with full sun, meaning at least six hours of direct sunlight on most days, to get the most yield from your lima beans. In addition to light for growth, full sun exposure also will help to keep the vines dry and less prone to fungal problems.

Soil

The soil should be well-draining and moderately rich in organic matter. Heavy clay soil can pose problems because lima beans have deep, expansive roots and don't like to sit in wet soil. The soil pH should be slightly acidic to neutral.

Water

Keep the soil evenly moist but not soggy until germination. Then, make sure the plants receive at least 1 inch of water per week. In hot, dry weather, mulch around the roots to keep them cool and to retain soil moisture. Pay extra attention to watering once the plants are in flower and start setting pods; they will drop the flowers/pods if they experience drought at this point.

Temperature and Humidity

Lima beans can be a bit temperamental about temperature. They don't like extremes and grow best in climates that stay between 70 and 80 degrees Fahrenheit for several months. However, they can handle warmer temperatures better than prolonged cool temperatures, and they aren't frost-hardy. Humidity typically isn't an issue as long as adequate soil moisture is maintained.

Fertilizer

Legumes generally don't need extra fertilizer, especially if the soil is already rich. However, because some lima bean varieties have a fairly long growing season, it can help to give them a side dressing of compost or composted manure mid-season. These slow-releasing sources of nutrients will help the plants continue for the rest of the season.

Pollination

Lima bean plants are self-pollinated.

Types of Lima Beans

Breeders are continually working to improve yields and come up with shorter-season varieties. Some varieties are better for long, warm-season climates, and others excel in more temperate zones. There are many heirloom varieties still being offered that perform as well as the newer varieties. Lima bean varieties include:

• 'Christmas': These large, burgundy-and-white beans have a potato-like texture. They are an heirloom variety and take 90 days to mature.
• 'Jackson Wonder': These buff-colored beans have burgundy speckles. They handle heat well and take around 66 days to grow.
• 'King of the Gardens': This popular variety has large white beans that are produced over a long season (around 88 days).
• 'Henderson’s Bush': This is an old and reliable variety with small white beans. It keeps producing for weeks and grows to maturity in around 65 days.
• 'Fordhook 242': A heavy producer of medium-size beans, this variety is a good choice for cooler climates. It takes around 72 days to grow to maturity.

Lima Beans vs. Fava Beans

Lima beans and fava beans have a somewhat similar appearance once they’re both shelled and dried. However, fava bean pods are typically bumpy while lima bean pods are smooth. Lima beans also tend to be starchier with a more mild flavor than fava beans, which some say have a cheese-like taste. 

Harvesting Lima Beans

Know when your bean variety should be ready for harvesting, as this can fluctuate from approximately 60 to 90 days. Harvest lima beans at the shelling stage or the dry stage. Lima beans are ready for shelling when the pod changes color, the beans inside plump up, but before the pod and seeds dry. If you want to harvest the beans to store as dried beans, leave the pods on the vine until they are dry and brittle, with the beans inside dry and hard. Hold the vine end when pulling off the pods to prevent damaging the vine.

Keep unshelled beans in the refrigerator for up to a week. Or shell and blanch beans to freeze for up to three months. Dried beans can be stored in an airtight container in a cool, dry spot for several years. Allow the beans to dry directly on the plant until the seeds are hard and the pods are brittle.

How to Grow Lima Beans in Pots

If you don't have garden space or the right soil conditions, container growing can be a good option. Choose a container that's at least a foot wide with a similar depth, and make sure it has ample drainage holes. An unglazed clay container is beneficial because it will allow excess soil moisture to evaporate through its walls. Water when the top inch of soil feels dry, but make sure the soil doesn't get waterlogged. Also, add stakes or another type of support structure for the container plant to climb if it's a vining variety.

Pruning

Pruning isn’t essential. But pinching back the top couple inches of growth as the plant begins to flower can help to promote a bushier habit and potentially more flowering and fruiting.

Propagating Lima Beans

Most gardeners grow lima beans from seed. And you can save seeds from a mature plant to grow the next year. This is an easy and inexpensive way to get new plants, and it will allow you to duplicate plants that were especially good producers or whose taste you liked. Here’s how:

1. Allow the pods to dry out on the plant. Cut them off when they are brittle.
2. Arrange the pods in a single layer, and continue to dry them for at least two weeks indoors in a cool, dry spot with good air circulation.
3. Remove the seeds from the pods. Put them in an airtight container, and store the container in a cool, dark, dry spot.
   

How to Grow Lima Beans From Seed

Lima bean seeds take roughly seven to 18 days to germinate. To extend your harvest, you can succession plant seeds every two to three weeks as long as your growing season is long enough. Also, consider planting varieties that mature at different times to stagger your harvest.

If you have a short growing season, you can start seeds indoors around three to four weeks prior to your projected last frost date in the spring. Use biodegradable pots that can be planted directly in the ground or a larger container, so you don't have to disturb the seedlings' roots. You also can warm your outdoor soil faster in the spring by putting a black sheet of plastic over it prior to planting seeds.

Potting and Repotting Lima Beans

Use a quality all-purpose potting mix that drains well for potting lima beans. Avoid having to repot your bean plants by selecting a container that will accommodate their mature size, as they typically don't take well to having their roots disturbed.

Overwintering

As lima beans are annuals, meaning they complete their life cycle in one growing season, no overwintering will be necessary.

Common Pests and Plant Diseases

All the usual bean pests will seek out your lima bean plants. They commonly include bean beetles and aphids. Many rodents also love tender, young bean seedlings, so fencing is recommended to keep them out of your garden. The biggest disease problem is root rot, which you should be able to avoid with well-draining soil and proper watering. If you have a particularly rainy spell, be sure to turn off any automatic irrigation.