Green beans are a great addition to your market garden.

If you choose varieties that are appropriate for your farm, and give thought to planting dates, it’s possible to get high yields and keep them coming till frost.

Green beans for shelling (harvesting when dry or eating fresh out of the pod when the beans are plump) are an easy crop in the right climate.

We will be drawing on advice from Pam Dawling, author of Sustainable Market Farming, as she has many years of experience with growing green beans on her farm. 

Green Bean Varieties

Provider and Bush Blue Lake snap beans are great for productivity and flavour.

You can sow reliable quick-maturing Provider beans (50 days) for the early and late crops.

Bush Blue Lake beans (57 days) are sown during the main season.

Contender beans have more flavour than Provider, but is less productive.

Jade Beans are delicious and tender and grow well in hot weather, but will be a big fat failure in cold conditions.

Romano II is a flat bean and is a reliable producer of tasty beans whether it is hot or cool, wet or dry.

If you have a market for yellow (wax) beans, you can grow these for visual diversity, although the flavour is not much different from green beans.

Purple-podded beans look attractive while raw, although the colour fades while cooking.

Pole beans require trellises, so if you prefer to stand to harvest beans, they might be worthwhile.

If you find putting up trellises a pain, you will probably prefer to grow bush beans.

Pole beans take a few days longer to mature, but can be picked for a longer period.

Half-runner beans can be grown with or without trellises and are capable of high yields.

However, Pam and her team have not found any that they like.

Crop Requirements

A soil temperature of 77 degrees Fahrenheit  (25° Celsius) is best for germination, although a temperature of 55 to 60 degrees Fahrenheit (13 to 16 degrees Celsius) and rising works for dark seeded varieties.

Air temperatures of 65 to 85 degrees Fahrenheit (18 to 29 degrees C) are best for growth.

Like all legumes, beans produce nitrogen in their root nodules, although this may not peak until after the beans are harvested. 

To grow strong plants you can fertilize before sowing at about 120 lbs N/acre, then use the bean produced fertility for the following crop.

If your soil is already very fertile you may not need to fertilize before sowing; as excess nitrogen will produce lots of leaves but delay flowering. 

Eighty to 85% of the nitrogen produced ends up in the bean tops, so if possible turn the tops under before planting the next crop rather than moving them to the compost pile. 

The nitrogen is produced by nitrogen-fixing bacteria in root nodules, so if you are growing beans on land that has not grown legumes before, or it’s spring and you don’t want to rely on the existing bacteria waking up, adding some powdered inoculant is a good idea.  

Many Growers add this at each sewing. It is cheap and easy, especially if the beans have been soaked, as it sticks better on the wet seed. 

Just before sowing drain the soaked seed, scatter some of the black powder on the beans as if you are adding pepper to your dinner, and stir gently. Each bean needs only a few specks of the inoculant to get started.

Beans tolerate a wide pH range, like plenty of sun, and well-drained soil. They definitely do not thrive if flooded.

An open site with good air drainage will help minimize mold problems and other leaf diseases.

Crops take 50-62 days from sowing to the first harvest.

Sowing 

On average, depending on your climate, the first sowing day is 10 days before the last spring frost date. The bed can be covered with a row cover if need be.

The last sowing is in early August, with the beans maturing before the first frost in mid-October. If your climate is different, you will have to adjust your sowing dates accordingly.

When frost threatens your planting, you can cover the beans with a row cover on cold nights. This should allow you to get several more pickings before any serious cold weather arrives.

Beans are mostly self-pollinating so row covers do not stop pollination, and beans that have already set can grow to full size more quickly. 

Dark seed varieties are more resistant to rot in cold soils, so use these at least for the first spring sowing.

Ensure the soil has enough water before you sow, and if possible avoid irrigation for 2 weeks after sowing. This reduces the chances of chilling injury to the seed from the cold water, soil crusting, and even the seed rotting. 

To speed up germination if the soil or weather is at all dry, soak the seed overnight (up to eight hours) in tepid water.

In cool wet conditions, it may be better not to soak, as the seed could then rot. 

If you have to postpone the sowing after soaking the beans, rinse them twice a day and drain.

Plant within three or four days, if you wait any longer the rootlets will be too long and fragile. 

Sow 1 inch deep, a little shallow in spring for warmth, a little deeper in hot weather for moisture.

Place the seeds 2 or 3” apart. 

Use wider spacing for new seeds and closer planting for 1-year-old seed. Two-year-old beans often have a germination rate of only 50% and are not worth planting.

Green Bean Cultivation

Do not cultivate or harvest green beans while the leaves are wet. This is because Anthracnose  (a bacterial blight), and rust disease are most likely to spread under these conditions. 

Hoe or machine cultivate while the bean plants are still small, and once they grow taller and bush out, few weeds will cause trouble.

Irrigation is most beneficial during bloom, pod set, and pod enlargement.

Try to time overhead irrigation so that the leaves dry before nightfall to prevent disease.

Beans need about one inch of water per week until the end of May, then up to double that in summer. 

Crop Rotations

Beans are not planted until spring is well underway, so beds for beans can grow good cover crops ahead of the cash crop. 

Winter rye should be turned under 3 weeks ahead of sowing, to allow the allelopathic compounds to break down. 

Two weeks should be enough time between tilling and sowing the next crop if you use wheat as your cover crop.

You should avoid legume cover crops ahead of legume food crops, to reduce the likelihood of spreading pests or diseases.

For this reason, it is better to grow beans where there have not been any other legumes for 3 years.

For more information, check out Cornell University’s 2016 Production Guide for Organic Snap Beans for Processing. It includes information on soil and plant nutrition, organic IPM strategies, and pesticides along with test results showing the relative effectiveness of the products mentioned.

Succession Planning

To calculate the best planting dates for your farm, you will need four pieces of information:

1. The first possible planting date in Spring.
2. The first harvest date from each sewing you’ve done.
3. The last planting date that will provide a crop in time before fall frost.
4. The number of days you want to be picking from the same plants.

To ensure a continuous supply of green beans with a new patch coming in to harvest regularly, first determine the earliest and latest possible harvest start dates based on your climate.

Divide the time period between the first and last date into a whole number for even lengthed intervals.

For example, if there are 100 days in between your earliest and latest date, you may choose 5 intervals of twenty days.

Therefore, if you want fresh beans every 20 days, you’ll need five intervals between plantings, which is 6 sowings total.

Pests

One of the worst pests of beans is the Mexican bean beetle (MBB),  a yellow bronze beetle with 8 black spots.

Adults overwinter in surface plant debris, so it’s important to clean up well in the fall, and try not to plant your first bean crop near the site of your last one the previous year.

The MBB tend to emerge on the first cloudy day in early June. 

A way to deal with MBB is to plant a small early crop of beans deliberately at or near the site of the late beans the previous year. A week later, sow a larger production planting as far distant as possible from the first. 

Then, flame the trap crop (the first one) when there are larvae, but not yet any pupae. 

Other insects that can damage bean crops include:

• Potato leafhopper
• Seedcorn maggot
• European corn borer
• Tarnished plant bug
• Mites
• Slugs

Rabbits and deer can also cause trouble. Dogs, fences, and guns are the most effective ways to control mammal pests.

Diseases

The main defense against disease is to keep the leaves as dry as possible.

Consider orienting the rows to take advantage of the prevailing winds, planting on raised beds, using wide row spacing or in-row plant spacing.

Fungal diseases tend to be furry. 

Botrytis grey mold can be tackled with neem extract.

Sclerotinia white mold can be avoided by rotating susceptible crops with sweet corn or other grass crops.

Avoid nightshades, brassicas, lettuce, or other legumes preceding your bean crops.

Bacterial diseases of beans cause brown spots,  which may have paler margins, on leaves and pods.

Virus diseases cause leaves that are typically mottled, blistered, or curled. 

It’s a good idea to scout the fields once a week or more and keep a weather eye open while harvesting or cultivating.

This will allow you to spot small problems before they become large ones. 

Harvest

Pick beans three times a week, going for thinner than pencil-sized pods.  Depending on your climate, beans can size up in 2 days.

It’s important to train your crew to nip through the stem of a pod and not leave the cap part on the plant as removing the cap signals to the plant to continue cranking out the beans, not to stop and focus on ripening seed.

For the same reason, it is also important to pick and discard any oversize pods.

Post-harvest

Beans are liable to chilling injury if enthusiastically refrigerated.

Keep the temperature above 40 degrees Fahrenheit (4.5 degrees Celsius) or you risk the beans becoming slimy and pitted.

Store for 7 to 10 days at 95% humidity and 40 to 45 degrees Fahrenheit (4.5 to 7 degrees Celsius). 

Temperatures above 45 degrees Fahrenheit (7 degrees Celsius) are likely to lead to yellowing and the development of fibre. 

If you have any bean tips to add, please feel free to comment down below! 

Stay Local, 

Kathy & Jon

your friendly neighbourhood growers