Growing Scarlet Runner Beans
Updated: Sep 15, 2022
This legume makes for a beautiful flowering plant – but they’re also edible! Originating in North America, scarlet runner beans have a nutty flavor and dry easily for storage.
The flowers and young green pods can also be enjoyed as a leafy green addition to your favorite salad! An extra bonus is that the flowers also attract pollinators and hummingbirds.
To help ensure your Scarlet Runner Beans thrives, we’ve put together this how-to video and transcript, making it easy for you to succeed. :) We’ll cover everything you need to go from seed to harvest and every step in-between. Covering topics like:
Glossary of Scarlet Runner Beans terms
Varieties of Scarlet Runner Beans available
Starting your Scarlet Runner Beans seeds
Caring for Scarlet Runner Beans at all stages
Fertilizer and/or mulching
Transplanting best practices
Companion Plants do’s and don’ts
Common Problems and Their Solutions
Pests, Diseases and what to do about them
Harvesting and storing your Scarlet Runner Beans
Glossary of terms for scarlet runner beans
Before we get started, let’s learn a little bit about these beans!
A type of plant that has no persistent woody stem above ground.
A plant that lives for at least two growing seasons. Runner beans are botanically different than regular pole beans. They prefer cool summer weather and drop their blossoms if it gets too hot!
Varieties of scarlet runner beans
You’ve got lots of beautiful options to choose from!
This variety has intense crimson flowers and jet-black seeds.
A variety that has pink flowers.
A variety with white flowers and string-less pods.
Similar Varieties: White Dutch Runner This type has flowers and white seeds.
The pods of this variety are stringless.
Golden Sunshine: This type has chartreuse- green foliage.
Painted Lady: An heirloom variety with bi-colored red and pink or white flowers on a vigorous vine. The seeds are cream-colored, streaked with deep brown markings.
Scarlet Emperor: This variety produces heavy crops of long, stringy pods and black and purple mottled seeds.
Scarlet Runner: This variety produces burgundy and black mottled seeds.
Planting Scarlet Runner Beans
To cultivate your own beans, find a sunny spot with well-drained soil and enough space for a trellis or something similar. This will allow your beans to climb vertically as they grow.
Also, your soil needs be warm(ish) – if it’s not warm enough, seeds will rot, especially if they’re untreated. Their preferred soil temperature is between 70-90°F (21-32°C), and their ideal soil pH is between 6.0-6.8.
The seeds are relatively large and should be planted 2-3 inches (5 to 7.5 cm) apart and 1.5 inches (3.5cm) deep at the base of support.
Typically, seeds will sprout in 8-16 days, depending on their soil conditions.
For transplants, you’ll want to sow 2-3 weeks before the last frost by planting two seeds 1 inch deep in individual cell packs or containers. Then, you can thin to one plant per cell or pot.
Important: Your soil needs to be warm enough to germinate, otherwise, seeds will rot.
Caring for scarlet runner beans
We’ll tell you everything you need to know about thinning and watering best practices, along with how to fertilize and mulch your beans. We’ll also share tips for transplanting, companion plants, and growing structure options!
The ideal air temperature for beans to grow is between 60-85°F (15-30°C). Keep in mind that pod set is often poor when temperatures are higher than 90°F (32°C).
Runner beans need pollination by bees to set their seeds – so if you can attract bees to your garden, it’s in your beans’ best interest!
You’ll also want to thin your beans to be 4-6 inches (10-15 cm) apart once your plants are about 2-3 inches (2-3 cm) tall.
Also, make sure to remove all young weed seedlings by hand or with a hoe, and use mulch on each side of the row to keep weed seeds from germinating.
It’s also important to keep the root zone moist by watering your beans deeply and regularly during dry periods.
Lastly, you’ll want to water more frequently once the pods begin to develop.
A few extra considerations
Plant your beans every 2-3 weeks, starting once the frost has passed for a continuous harvest.
You’ll want to cover your seeds with a quarter to a half-inch of soil or compost. Then, keep the soil moist but not soaking wet until your seedlings emerge.
Finally, pick your beans regularly to keep your plants producing more!
FERTILIZING AND/OR MULCHING
Use 1 cup of a complete organic fertilizer for every 10 feet of row.
Please take note, though, that too much nitrogen fertilizer can delay your plants’ maturity and affect their pod production.
If your beans flower but do not set pods, the cause can sometimes be a zinc deficiency.
Try spraying your plants with a kelp-based fertilizer, and also avoid using a nitrogen fertilizer until your bean plant has developed some flowers.
In most cases, the best fertilizer to use on scarlet runners has a balanced mixture of nitrogen, phosphorous, and potassium in a ratio of 10-10-10.
A thick layer of mulch will help keep your soil moist between waterings. You can use organic material like straw, hay, or grass clippings to mulch your bean plants.
TRANSPLANTING BEST PRACTICES
Harden-off your seedlings first before you transplant them outside – and make sure to wait until after the last frost before setting your transplants into your garden.
Once that frost has passed and your soil has warmed to 50⁰F, transplant your beans.
Be sure to install a trellis before your plant your seedlings.
If you try to install the trellis after you plant, you can risk injuring or killing your bean plants.
GROWING STRUCTURE OPTIONS
Build a strong trellis that’s about 6-8 feet (2-2.5m) tall, as your bean plants will climb by twining around it. Scarlet runner bean vines will quickly and brilliantly cover fences, trellises, and other garden structures, and they can climb 10-12 feet tall – pretty cool!
Till your soil to a depth of 8 inches to get it loose and aerated. Add a layer of compost about 2-4 inches deep over your garden area, then mix it into the soil thoroughly using your garden hoe.
CELL TRAYS OR CONTAINERS
Ensure that the cell trays or containers you’re using have drainage holes. Cell trays allow your beans to develop their root system better, which is vital for their growth.
COMPANION PLANTS DO’S AND DON’TS
Common challenges and their solutions
There are quite a few pests and diseases that can potentially harm your beans. Not to worry – we’ve listed them below, along with how to either avoid or fix the problem!
These pests are usually a problem for the undersides of leaves and/or the stems of your plant. They tend to feed in groups and often spread diseases.
Solution: Use a strong water jet to wash them off your plants. Neem oil, insecticidal soaps, and horticultural oils are also effective against aphids -be sure to follow the application instructions on the packaging!
You can often get rid of aphids by wiping or spraying the leaves with a mild solution of water and a few drops of dish soap (one variation includes adding a pinch of cayenne pepper).
Soapy water should be reapplied every 2-3 days for about two weeks.
Young larvae will feed heavily on your plant’s leaves, skeletonizing them.
Solution: You can control armyworms by introducing their natural enemies into your garden or applying certain (safe) bacteria.
Its larvae will damage leaves, buds, flowers, pods, and beans. Young caterpillars are a creamy white color with a black head and black hairs.
Solution: Make sure to monitor your plants for eggs and young larvae. Certain safe bacteria can be applied to control them, but keep an eye out for natural enemies that could be damaged by using chemicals (since natural enemies are another way to keep these pests in check!).
Insects that cut off seedlings at the soil level. They’re mostly a problem with young seedlings, so mature plants aren’t as vulnerable to damage.
Solution: Place a paper cup collar (like a disposable coffee cup with the bottom cut out) around the base of your plant.
You can also control cutworms by handpicking them and controlling weeds since that’s where they lay their eggs.
Pests that create irregular round-shaped mines on the leaves. These mines are long and narrow at first but eventually become irregular-shaped patch.
Solution: Natural enemies, especially some parasitic wasps, can reduce the number of leaf miners on your plants.
Also, certain sprays (like AZA-Direct or Neemix) are good to use on your plants.
MEXICAN BEAN BEETLE
Pests that leave irregular patches of feeding damage on the undersides of leaves, which then causes the top surface of the leaf to dry out.
They will give your plant’s leaves a lacy appearance and damage flowers and small pods – which can be damaged so severely that they drop from the plant.
Solutions: Since damage is most severe during the summer months, consider planting early-maturing bean varieties to avoid the issue. If you spot these beetles, hand-pick both the adults and immature beetles from your plants, and drop them in a pail of soapy water.
Also, be sure to remove the bright yellow eggs typically laid in clusters on the undersides of leaves.
Another option is diatomaceous earth, which contains no toxic poisons and works quickly on contact.
Dust it lightly and evenly over your crop wherever the pests are found.
Finally, if the infestation is heavy, you can apply insecticidal soap to the leaf undersides.
ALTERNARIA LEAF SPOT
Small, yellow-brown spots with a yellow or green halo will first appear on the oldest leaves. As the disease progresses, leaves will begin to curl and eventually die. This disease is common in growing areas with high temperatures and frequent rainfall.
Solution: Water your plants from below to avoid having soil splash up onto the lower leaves. If you can water from below using a soaker hose or drip irrigation AND provide a well-ventilated cover for your plants to protect them from the rain, you’ll be all set.
Be sure to clean any equipment between uses to prevent the spread of bacteria, and do not prune or handle your plants when they’re wet.
Also, establish a crop rotation and stick to it. If you spot some blighty leaves (usually on the bottom of the plant closest to the soil), remove and destroy them.
Initially, small yellow/white spots appear on leaves, growing and developing raised red rust pustules (gross pimple-like growths). If the disease is severe, it can cause your plants to drop their leaves prematurely.
Solution: Water your beans in the early morning hours to give your plants time to dry out during the day.
Drip watering and soaker hoses can also be used to help keep leaves dry¸ but avoid using overhead sprinklers.
Use a slow-release, organic fertilizer on crops and avoid excess nitrogen.
Also, prune or stake your plants and remove any weeds to improve air circulation. Ensure to disinfect your pruning tools (one part bleach to 4 parts water) after each cut.
Finally, use a thick layer of mulch or organic compost to cover the soil after you’ve raked and cleaned it well because mulch will prevent the disease spores from splashing back up onto your plant’s leaves.
Small water-soaked spots will appear on your plant’s leaves, which grow and turn tan or brown with a papery texture. The stems of your plants might break if they’re weakened by the lesions, while pods will dry and shrink.
This disease typically thrives in extremely wet weather, and its spores are usually spread by splashing water.
Solution: Plant disease-resistant seeds when possible. As well, avoid using sprinklers or overhead watering instead of watering your plants from their base to keep leaves as dry as possible.
If this fungal problem is common in your garden, do NOT save your own seed from plantings. To avoid spreading this disease, keep out of your garden when plants are wet and make sure to disinfect all garden tools after use - one part bleach to 4 parts water should do the trick.
Also, don’t compost any infected leaves, fruit, or stems and thoroughly clean up garden areas in the fall (after harvest) to lessen the chance that the fungus will survive over the winter.
Finally, Neem oil spray is an organic, multi-purpose fungicide that prevents fungal attacks on plants. It’s best to apply it early, at the first sign of spring budding.
Apply it every 1-2 weeks as a preventative measure or on a 7-day schedule until the problem is managed.
A disease that causes water-soaked spots on leaves that grow and turn brown. Those spots can be surrounded in yellow, and when the lesions come together, they give plants a burned appearance. At this point, any leaves that die will remain attached to your bean plant.
Circular, sunken, red-brown lesions might also be present on the pods and sometimes ooze out during humid conditions.
Solution: When possible, try to plant only certified seeds or resistant varieties. You can also treat your seeds with an antibiotic before planting to kill off the bacteria. Finally, spray plants with a protective copper-based fungicide before symptoms appear.
Flowers will get covered in a white, cottony fungal growth. Small, circular, water-soaked dark green spots will also appear on pods, leaves, and branches, which will grow and become slimy.
The cottony white growth may be visible on lesions when there’s high humidity, and the death of branches and/or your entire plant is also possible. This fungus can survive in the soil for more than five years and is spread by wind, contaminated water, and infected seeds.
Solution: There’s no true immunity to white mold in any bean varieties, so what you’ll want to do is rotate crops with non-hosts like cereals and corn and plant your rows parallel to the direction of dominant winds to prevent the spread of the disease.
Avoid using excessive nitrogen fertilizer, and also keep your rows spaced widely apart.
If you spot white mold on your plants, potassium bicarbonate is a safe, effective fungicide that kills spores on contact. Like baking soda, it’s also an excellent preventative treatment because it raises the pH level above 8.3—an alkaline environment that isn’t ideal for the fungus to grow.
What you’ll want to do is mix 3 tbsp. of potassium bicarbonate, 3 tbsp. Vegetable oil, and 1/2 tsp. soap together into a gallon of water, then spray it onto your affected plants.
Baking soda itself has a high pH of 9, so it can also help raise the pH level of your plants and create a very alkaline environment that kills the fungus. Typically though, it’s best used as a preventative treatment rather than a fungicide.
Mix 1 tbsp. Of baking soda and a half tsp. liquid hand soap with one gallon of water, then spray the solution on affected leaves
Don’t apply it during daylight hours. It might also be best to test one or two leaves first to see if it causes sunburn to your plants.
Long red-purple lesions will appear on the roots, turning dark gray to black. Lesions will come together to form large dark areas on the roots and stems, and if they’re deep enough, they can stunt your plant’s growth, cause the leaves to wilt or drop, or even kill your plant entirely.
Typically, this fungus survives in plant debris in the soil.
Solution: Make sure you keep your soil moist and give your crops the best temperature to grow, both in the air and soil.
You can also incorporate plenty of organic matter into your soil before planting to raise its quality and keep it from compacting.
Also, if your soil is not well-draining, either amend it to improve the drainage or plant your beans in raised beds.
If you already have diseased plants, remove them first and then treat your remaining plants with fungicides to protect them.
Finally, keep your soil’s pH less than 6.5, and clean and disinfect reused plastic trays and containers properly.
This is one of the most common problems when starting plants from seed. Seedlings will emerge and appear healthy; then, suddenly, they’ll wilt and die for no apparent reason.
Damping-off is caused by a fungus that’s active when there is lots of moisture and when soils and air temperatures are above 68°F (20°C).
Solution: Keep your seedlings moist but do not overwater them, and avoid over-fertilizing as well.
Thin out your seedlings to avoid overcrowding and to promote good air circulation.
Also, when planting in containers, make sure to thoroughly wash them in soapy water and then rinse them in a 10% bleach solution after use.
Harvesting and storing
The edible beans grow up to a foot long and are especially good when picked young. As well, you can pick them often to promote continued flowering.
In general, beans can be picked once they’re plump-looking. The pods should be tender and break easily with a snap when ready.
You can either dry your beans to preserve them or cook them soon after harvesting.
You can store your beans in a perforated plastic bag in the fridge for up to a week.
Beans also freeze well – all you have to do is clean the beans, trim their ends, and snap them.
Blanch for one minute in boiling water, then plunge into ice water for another minute and then drain them thoroughly before you stick them in the freezer.
IMPORTANT: ensure that you cook these beans thoroughly! Raw runner beans contain lectin, which is a toxin that’s removed by the cooking process.