Here I’m talking about snap beans, both bush beans and pole beans, often simply called green beans. You can get good yields all summer long until frost if you pick the right varieties and plan when to plant them.
We like Provider and Bush Blue Lake snap beans for productivity and flavor. We often sow Provider for the early and late crops, with Bush Blue Lake during the main season. Contender may have more flavor, but is less productive then Provider. It’s a tasty, very tender bean that does best when it’s hot outside but fails horribly when it’s cold outside. We plant six plantings of bush beans in a row so that we always have some that are at their best.
People who like flat beans often choose Romano II because he always makes tasty beans, whether they are hot, cold, wet, or dry. Some people like wax beans because they look different, but they don’t taste much different from green beans. Purple-podded beans look attractive while raw, although the color fades on cooking.
We have given up on pole beans as we don’t like putting up trellises. If being able to harvest while standing is better than having to set up a trellis, you’ll choose pole beans over bush varieties. Pole beans take a few more days to fully develop, but they can be picked for longer if the Mexican bean beetle doesn’t damage them. Half-runner beans can be grown with or without trellises, and are capable of high yields. We haven’t grown any we really liked.
Green beans are a favorite vegetable for many home gardeners. Their versatility and nutrients make them an essential part of any healthy diet. However, as a warm season crop green beans require moderately warm temperatures to thrive. This leaves many gardeners wondering – can green beans survive 40 degree temperatures? Let’s take a closer look.
An Overview of Green Bean Temperature Tolerance
Green beans grow best with daytime highs between 70-85°F and nighttime lows above 50°F However, they can withstand short periods in the 40s if properly cared for Prolonged exposure below 40°F can damage plants. Here’s a quick overview
- Ideal Temperature Range: 70-85°F
- Minimum Temperature: 40°F
- Frost Tolerance: Light frosts (around 40°F)
- Hardiness: Can survive short 40°F periods with care
- Damage Risk: High below 40°F or with prolonged cold
Caring for Beans in Cool Temperatures
When temperatures drop near 40°F, proactive care can mean the difference between thriving beans and damaged crops Here are tips to help beans survive
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Use Protective Coverings: Row covers, plastic sheets, or garden fabric can shield plants from cold snaps.
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Provide Mulch: A 2-4 inch layer of mulch insulates soil and protects roots.
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Water Well: Hydrated plants better withstand cold temperatures.
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Harvest Existing Beans: Pick beans so the plant’s energy goes toward protection not pod growth.
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Prune for Airflow: Remove excess foliage to allow airflow and light penetration on cold days.
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Monitor Soil Temperature: Use a thermometer to check for dips below 40°F around plant roots.
Taking these proactive steps when cool weather hits can help bean plants endure temperatures in the 40s. But avoid prolonged exposure below 40°F.
The Impact of Prolonged Cold on Beans
While beans can survive short periods of 40°F weather, extended cold exposure causes significant harm:
- Damaged blossoms and aborted flowers/fruit
- Poor pod fill and stunted development
- Leaf necrosis, yellowing, and plant decay
- Rotting stems, roots, and overall decay
- Plant death after a couple weeks below 40°F
If long stretches with highs in the 40s or nights below 40°F are forecasted, beans will need extra protection or should be harvested before the cold hits. Let’s look at timing and varietal differences next.
Bean Varieties and Planting Timing Considerations
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Plant Tolerant Varieties: Some green bean varieties better withstand cold including Blue Lake, Oregon Trail, Jade, Contender, and more. Choose one of these to improve cold hardiness.
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Delay Planting: Wait until nightly lows are reliably above 40°F before sowing beans. This avoids cold damage.
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Start Indoors: You can begin beans inside 4-6 weeks before last frost, then transplant seedlings for earlier harvests.
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Use Season Extenders: Low tunnels, cold frames, and greenhouses allow earlier planting and prolonged fall harvests.
With the right varieties and timing, you can maximize harvests while minimizing frost and freeze risks to your bean crop.
Common Questions about Green Beans in Cool Weather
Here are answers to some frequently asked questions about green beans and cooler temperatures:
Can green beans survive a light frost?
Yes, green beans can typically survive a light frost down to about 40°F thanks to their cold hardiness.
What temperature do green beans start to die?
Temperatures below 40°F will start to damage and potentially kill green bean plants if exposed for long periods.
Should I harvest green beans before a frost?
It’s advisable to harvest existing green beans before a hard frost below 32°F hits. Leave some beans to assess damage after a light frost.
Can you plant green beans in cold soil?
Green beans need warm soil at least 50-65°F to germinate and become established, so avoid sowing until soils have warmed.
Can I cover plants to protect from frost?
Yes, cloches, commercial row covers, plastic sheeting, fleece, or garden fabric can effectively shield plants from frosts and cold weather.
Conclusion
Carry on sowing beans as late as sensible
To find the last good date to plant, take the first frost date and subtract the number of days from planting to harvest. Next, go back two or three weeks, or however long you think is a good harvest period for you. If you don’t have rowcover for when it gets cold, move your planting dates back one or two weeks in case the frost comes early. Our first frost could be October 14, and counting back 60 days gets us to mid-August. We go with a last sowing in early August. We pay attention to weather forecasts, and when frost threatens, we cover with rowcover on the cold nights. Usually this lets us get several more pickings before any serious cold weather arrives. Row cover would stop pollination during the day, but it wouldn’t stop beans that have already set from growing to their full size.
Prepare for green beans
Beans tolerate a wide pH range, and like plenty of sun and well-drained soil. They don’t do well in water! An open area with good air flow will help keep mold and other leaf diseases to a minimum. Bush beans harvest in 50 to 62 days, or a little less if the soil is really warm. A soil temperature of 77°F (25°C) is best for germination. For dark-seeded varieties, a temperature of 55–60°F (13–16°C) and rising will also work. Air temperatures of 65-85°F (18-29°C) are best for growth.
Beans, like all legumes, make nitrogen in their root nodules, but the production peaks after the beans are picked. You can use about 4 oz N/100 sq ft (13 kg) of fertilizer before the beans to make the plants strong. 4g/sq m), and use the bean-produced fertility for the following crop. If your soil is already very fertile, you could skip fertilizing before sowing the beans. Excess nitrogen will produce lots of leaves but delay flowering. Between 20% and 85% of the nitrogen that is made ends up in the bean tops, so if you can, turn them under before planting the next crop instead of putting them in the compost pile.
Bean beds can grow a good stand of winter cover crops before the bean crop because they aren’t planted until well into spring. Before planting, winter rye should be turned under for three weeks. This will let the rye break down and the allelopathic compounds break down. Our research has shown that wheat is easier to mix in and doesn’t stop the next crop from sprouting as much. People usually don’t plant legume cover crops before they plant legume food crops. This is done to keep pests and diseases from spreading. For the same reason, it’s better to plant beans in places where no other legumes have grown in three years. To stay away from Sclerotinia white mold, plant nightshades, brassicas, lettuce, and other legumes, and alternate with sweet corn or other grass crops.