Days to germination: 4 to 7 days
Days to harvest: 60 to 90 days
Light requirements: Full sun
Water requirements: Regular watering
Soil: Loose and fertile, with no added nitrogen
Container: Bush varieties are best
Lima beans are one of those stereotypical vegetables that kid’s are supposed to hate, but they really are extremely healthy.
Sometimes called butter beans, lima beans are extremely high in fiber, protein, and magnesium. They also contain another chemical compound that is toxic if the beans are eaten raw. Once cooked, it becomes harmless. Needless to say, no one should eat raw lima beans. Lima beans can either be cooked from fresh or after they have been dried.
Lima beans come in varieties that grow in a bush, and those that vine (also referred to as determinate and indeterminate plants). Typically the vining bean plants will take longer to mature.
Starting from Seed
Lima beans can be started indoors if you want to start your plants early, because they can only go outside well after the frost date which can mean a short growing season in some areas.
Plant your seeds in seedling pots about 3 to 4 weeks before the last frost date in your area, and keep them moist until they sprout. Seeds should be planted at least 1 to 2 inches deep in the soil. The seedlings will be a little delicate for transplanting, so you should start your seeds in paper or peat pots that can be planted without having to dislodge the plant.
Only use loose soil over the seeds to make sure they can break through the surface. They aren’t particularly strong sprouting seedlings.
It is time to put your seedlings out 3 weeks after your frost date, or you can sow your seeds out at this time if you are not using seedlings. The soil needs to be well warmed after all frost has passed (at least 65F).
Lima beans do best in sunny locations, and you will have to space your plants out depending on whether you are growing bush or vining beans. Bush beans should be 4 to 6 inches apart, and vining bean plants should be a little farther apart at 8 to 10 inches away. If you want to use a hill system for vining beans, you can plant 4 or 5 close together, but then allow at least 30 inches between each hill.
If you are putting out seeds rather than seedlings, use very loose and non-compacted soil to cover the seeds, as mentioned above.
Set up poles or a trellis for vining beans right after (or even before) you plant so that you don’t do any damage to the growing plants when they are larger. Bush beans may need cages to help keep them compact, but they shouldn’t require any more support than that.
Like with all beans, you need to stay away from nitrogen around your lima beans. That means no high-nitrogen fertilizer and no fresh manure. The extra nitrogen may seem to help because your plants will start to grow quickly but the extra growth is all leaves and no beans.
Water your beans regularly so the soil stays consistently moist. This is particularly important when the pods have formed and the beans are developing. Uneven watering can lead to split or cracked beans. Rather than water every day, add a layer of mulch to help prevent water loss from the soil.
Any type of lima bean plant will grow in a pot, but most people who do container gardening stick with bush varieties like Henderson or Fordhook. Each pot should be 8 to 10 inches across, and longer than that in depth. You’ll need several plants for a reasonable harvest if you use lima beans more than just occasionally.
Potted plants may need some fertilizer, but you should use a blend with no nitrogen to keep your plants producing beans rather than leaves.
Pests and Diseases
Various fungal spores can persist in the soil for 2 to 3 years, so you should plant your lima beans (any beans for that matter) in a different area every year to keep infections to a minimum. In particular, you need to watch for blight and anthracnose.
With anthracnose, you will see black blotches along the stems and leaves. Your seedlings may be effected right from the moment of sprouting, so make sure to start watching early. Fungicides may help but plants usually die. Pull infected plants immediately, and it may not spread.
You can buy resistant varieties of plants that will make this less of a danger, and you should also water your plants at the soil level rather than from above. Frequently wet leaves will help spread the fungus spores.
Insects are also a problem with lima beans, and can be targeted by several different species of bean beetle, caterpillar and aphids. Aphids can be washed off with water, though they are relatively harmless. Pick off beetles and caterpillars as soon as you see them, and treat your plants with a natural insecticide (ones with pyrethrins work great) to help keep them away.
Harvest and Storage
Beans are ready to pick when their pods are completely filled out. If you leave them until the pods start to dry, the beans will be tough and nearly inedible. Even if you intend to dry your beans, these are not to be left on the plant to dry. Pick them when they are ripe and still green. The pods are not edible.
Picking pods as soon as they are ready will encourage the plant to continue producing more pods. Once one or two pods pass this stage and get over-grown, the plant will usually stop blooming and stop making new pods.
Bush beans tend to ripen up all at the same time, but pole beans produce their pods over a longer period of time.
You can use your fresh lima beans right away, or dry them for longer storage. Fresh ones will last in the fridge for a few weeks, and you can also freeze them (blanche them first). For much longer storage times, dry your shelled lima beans until they are completely dried through.
Once dry, they will store in a tight-container for 8 to 10 months in a cool location.