Step inside my garden and rarely will you see a garden bed left empty for more than a few weeks, even when all my plants are done for the season. When soil is bare and untended during the winter months, it can lead to depleted nutrients, compacted soil, and tenacious weeds that pop up at the earliest signs of spring.
That’s why I’m a fan of using cover crops to protect the soil and improve fertility over winter, particularly edible cover crops like fava beans and bell beans.
Read more: More of my favorite edible cover crops that build your soil while they grow
These cold-hardy plants easily survive temperatures of 15°F to 20°F. They’re not as hardy as Austrian winter peas (another excellent cover crop), but are pretty close and can be grown in most climates. They even love the snow and will grow right through it!
Fava beans and bell beans are easy-to-grow legume cover crops that fix nitrogen in the soil—that is, they add significantly more nitrogen to the soil than they use for their own growth. Once they start blooming, they’re cut down to the ground so other plants can take advantage of their stored nitrogen.
Is there a difference between fava beans and bell beans?
Bell beans are simply a small-seeded variety of fava beans (Vicia faba, also known as broad beans). Unlike standard large fava beans, bell beans are usually grown as a cover crop rather than a food crop. It’s not that bell beans are superior to favas—it’s just that the small seed sizes make it easier to plant them mechanically in the field, so they’re the type used on farms.
Other than that, fava beans and bell beans are essentially the same plant. They both have edible leaves and flowers that taste faintly bean-like and are best used fresh in salads, sandwiches, and creative pestos.
How fava beans enrich the soil
Fava beans can “make” fertilizer by fixing nitrogen in the soil (putting in more nitrogen than they take out). And since they can make their own nitrogen, they don’t need to be fertilized.
You see, there’s plenty of nitrogen to go around—about 80 percent of the atmosphere is free nitrogen, but it floats around in a form that plants can’t use.
Enter legumes like fava beans and bell beans: They’re unique in their ability to form a symbiotic relationship with harmless soil bacteria called Rhizobia. The legumes provide food (sugars and other nutrients) that sustain the Rhizobia. In return, the Rhizobia pull nitrogen gas out of the air and convert it into ammonium compounds that plants can consume.
Fava and bell beans store nitrogen in small white sacs on their roots called root nodules. When the plants are cut down—and more importantly, when the roots are left underground to decompose—the root nodules release the stored nitrogen for other plants to use.
That means when you plant your next crop, you can reduce (or even skip) the initial fertilizer application because those plants will already be off to a great start.
Disclosure: If you shop from my article or make a purchase through one of my links, I may receive commissions on some of the products I recommend.
When to plant for maximum soil-building benefits
Fall planting: In climates that never drop below 15°F, bell beans are ideal for late summer to mid-fall planting (typically from September to mid-October) because they germinate quickly, thrive in cold weather, and are one of the few fruiting plants that tolerate some shade. They overwinter easily and protect and replenish your soil over winter.
Fava and bell beans start flowering anywhere from 90 to 200 days after a fall sowing. This timing is ideal for planting heavy feeders like brassicas (broccoli, cabbage, kale, cauliflower) right after you turn the cover crop into the soil.
Spring planting: In harsher winter climates, you can sow fava and bell beans as a cover crop in late winter to early spring as soon as the soil is workable. I’ve found that they’re more tolerant to heat than Austrian winter peas, so they’ll happily grow into summer when peas generally start struggling.
Fava and bell bean plants typically start flowering about 40 to 60 days after a spring sowing. Timing-wise, that means a spring-sown crop should be turned into the soil between May and June, so think about how this affects your planting schedule.
If you plan to overwinter your bell beans: Sow seeds roughly four to six weeks before the first hard frost so the plants are at least 6 to 8 inches tall before growth stalls.
If you plan to grow bell beans in spring: Sow seeds once the soil temperature is at least 40°F (though germination will be faster if the soil temp is between 50°F and 75°F).
Read more: Find out when your area is expected to get its first frost
Planting schedule by growing zone
(Scroll right on mobile)
|
Zone |
Plant By |
Overwinters? |
Turn Into the Soil By |
|---|---|---|---|
|
Zones 4–5 |
Late August to mid-September |
Generally winterkills |
Turn in spring or leave crop residue as mulch |
|
Zones 6–7 |
Mid-September to October |
Overwinters with mulch or frost cloth in most years |
Turn in March to April |
|
Zones 8–10 |
October to November |
Overwinters reliably |
Turn in February to March |
How to plant fava beans as a cover crop
If your garden is less than perfect, rest assured that fava beans and bell beans can easily be grown in deficient soil or clay soil (after all, their job is to make it better). They won’t be happy in waterlogged soil though, so try to plant them where there’s good drainage.
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Step 1: Inoculate your seed.
To maximize the nitrogen-fixing capabilities of your bean crop, seeds should be inoculated before planting. Doing so helps get the right kind of Rhizobia bacteria into the soil that your plants need for their nitrogen stores.
(Inoculant has a limited shelf life since it contains live beneficial bacteria. I always recommend buying fresh inoculant each year just to be sure you get the bacteria in your soil.)
Recommended
Bean inoculants
Though it isn’t strictly necessary, you can also soak bean seeds for a few hours to speed up germination. This is especially helpful if the weather is still dry when you plant and you want the seeds to germinate quickly.
Step 2: Sow seeds about 6 inches apart and 1 inch deep.
If I was the type of gardener who spaced plants perfectly in rows, I would tell you to space your plants in rows 12 to 18 inches apart to give them room to breathe. That’s what you should do.
But when I plant a cover crop that doesn’t mind growing more densely, I prefer to broadcast the seeds over my garden bed and rake them into the soil about 1 inch deep. It’s okay if some seeds aren’t fully buried; as long as they stay moist, they’ll germinate.
In dry climates or very cold climates, adding a layer of straw mulch on top will help hold moisture between watering sessions and protect the soil over winter.
Step 3: Water thoroughly.
Keep the soil consistently moist but not soggy. Sprouts will appear that first week and grow several inches within a couple weeks (depending on soil and air temps).
If you sowed seeds in fall, keep in mind that plant growth will slow down significantly in winter. But as long your average lows stay above 15°F to 20°F, your cover crop will overwinter and resume growing in late winter to early spring once the days get longer.
Step 4: Add support for your plants.
Fava beans and bell beans are tall, thin, and top-heavy plants that require minimal staking as they grow so they don’t flop over under their own weight.
They’re well suited for those conical wire tomato cages that, ironically, don’t do a super job of supporting indeterminate tomato plants. But they’re fantastic for fava and bell beans!
You can also support them with bamboo teepees or wire plant stakes (the ring type usually sold as peony cages).
Recommended
Plant support rings
These half-circle wire plant supports can be used alone or in pairs to keep top-heavy plants from flopping over. I like the 32-inch version for supporting fava beans and bell beans.
When and how to turn the plants into your soil
Turning fava beans and bell beans into the soil means terminating the plants and letting them break down to enrich the soil.
Beans should be cut back when 25 to 50 percent of the crop is flowering. Don’t wait for the plant to make pods, because it’ll send most of its stored nitrogen to the seeds as it prioritizes filling the seeds rather than feeding the Rhizobia. That means less nitrogen will be available for your soil!
So watch for your crop to bloom and get ready to “turn it into the soil,” as they say in gardening parlance.
Traditionally, you would turn a cover crop into the soil by tilling, digging, or forking the plant material under the soil. But if you’re a no-till type of gardener, the “chop and drop” method is what I personally prefer: simply chop the plants down and spread them across the bed.
Cut them right at soil level (do not pull the plants up) so the roots stay in place underground. I find it’s easiest to do this with a pair of hedge clippers (I use the ones below).
Recommended
Hedge clippers
Lightweight and easy to use, these clippers are a staple tool in my garden shed. I use them for a variety of pruning tasks to trim, shape, or cut down plants at the end of the season.
Then wait about three to six weeks before planting your next crop. I generally recommend this because as your cover crop decomposes, some of the nitrogen in the soil will be temporarily locked up. After a few weeks, the decaying roots will release their nitrogen stores and the foliage will break down into mulch and nutrients for your next crop.
When you’re ready to plant, just push the stems and leaves aside, make your holes, and plant your seedlings. If you want to sow seeds, cover the decomposing foliage with a 2-inch layer of soil or compost (or a half-and-half blend) so you have a clean planting medium for your seeds.
Quick tip
Growing fava beans and bell beans as “free fertilizer” doesn’t mean you should skip fertilizer completely. But you may only need half as much nitrogen in an average season for heavy-feeding plants.
Recommended bell bean seeds
Growing the bell bean variety of fava beans as a cover crop or green manure (with no intention of harvesting for food) means you can buy seeds in bulk, rather than culinary fava bean varieties that are only sold 20 seeds to a packet.
Here’s what I recommend:
- Bell Beans: Sold by the pound
- Bush Bell Beans: Sold by the ounce and pound
- Small Fava: Forage-quality variety sold by the pound
- Sweet Lorane: Cold-tolerant down to the low teens (°F)
The big bean misconception
Many gardeners think that simply growing beans alongside their other plants will help pump nitrogen into the roots of these other plants.
But that’s a myth: Living legumes use most of their fixed nitrogen to grow their own leaves, stems, and flowers. They store the rest of their nitrogen in root nodules until that nitrogen is needed for seed production.
To actually get that nitrogen, you have to chop the plants down (before they set seed) and let the roots decompose in the soil instead of pulling them out. As the root nodules break down over a few weeks, they release the stored nitrogen for the next round of plants that go in.
Frequently asked questions
This post updated from an article that originally appeared on October 15, 2013.
This information is very informative. i am a Master Gardener in Mason County, Shelton, WA. A few of our MGs did an experiment in one 40 foot row in our demonstration / food bank garden this year. They planted a variety of cover crops together including rye. There were four or five different plants. The group told us it would help this years vegetables planted in this row this year. But, upon further investigating and reading, the cover crops will not help the soil for 4-5 years and they should have used a little fertilizer too. The group planted tomato plants and said it was hard to dig into the cover crops soil (after they cut it to the ground) to get the plants in. The tomatoes are not doing that well. Do you have any insight into this trial? We are trying to decide if we want to do a cover crop in other rows for next years vegetables garden. Thank-you so much. I love following your posts. I have learned a lot.
It depends on the types of cover crops your MG group planted. I primarily cover crop with fava/bell beans and Austrian winter peas, and have never had issues with digging into the soil afterward to transplant new plants (even gallon-sized plants). Legume crops are nitrogen fixers, so if the right kind of Rhizobia are present in the soil, they’ll release their stored nitrogen after being terminated (which helps the next round of crops that season, not in 4-5 years). So it sounds like your MG group planted cover crops for other reasons besides nitrogen fixing. If they planted radishes or clovers, that would definitely make it tough to get new plants in afterward. It’s the main reason I don’t recommend cover cropping with clover in a vegetable bed—it’s a very persistent ground cover with an extremely dense root system. It’s a pain to pull out of soil. You can read more about growing Austrian winter peas at https://gardenbetty.com/austrian-winter-pea-cover-crop/ and how Rhizobia works to fix nitrogen at https://gardenbetty.com/fix-nitrogen/
Dear Betty,I see you are an expert in gardening.Every summer I grow some Fava beans in my garden on the 20 of May. I grow them very tight to each other.i harvest them in late July or August .when I plant them outside I add some ground coffee and Epsom Salt. is it safe to add these two ingredients on? I am talking from Kingston/ Canada.
GREAT Issue, Linda! I grew favas (‘Windsor’ or something like that) in Western Massachusetts in the early 1970’s. We lived in a particularly cold area, and I could plant favas on a gentle south-facing slope as soon as the first two inches of soil had thawed. (I heated mostly with wood so I could spare the early leaching of fertility from ashes spread on snow to cause snowmelt.)
On of my online permaculture design students from South Africa, where they have a Mediterranean climate, astonished me by saying that local practice was not to have a winter garden. I recommended that she plant favas amongst other cold tolerant crops, especially brassicas. They had very dry summers she had established plantings of grapes and olives that thrived. It seemed to me that she could grow winter vegetables, especially favas, enough to store suitable types for summer use and grow drought tolerant crops such as artichokes and quinoa in the summer, though she would need a heat tolerant quinoa variety that may have been hard to access.
FLORIDA A while back one of your readers asked about winter crops for Florida. This varies considerably depending on the location as conditions differ not only north to south but along the panhandle. In North Central Florida I repeadly failed with winter favas, until I realized that they were developed in a rainy winter climate. From sometime in fall to sometime in spring is the Florida dry season. The beginning and end times vary significantly, but generally fire season is in spring. Peas are somewhat drought tolerant and are a good high protein winter crop there. Kale does well as a fertility preserving winter cover crop, though without much rain, little fertility leaches even from the sandy soil covering most of the state. That is another variable regarding winter crops. I also grew a lot of broccoli, pac choi (in a partly sheltered area), root crops, especially carrots, etc. I also grew moringa, which doesn’t grow in winter and some years back (before rapid climate warming) was repeatedly killed to the ground each winter. I grew winter vegetables between the moringas, often in containers so not to disturb the moringa roots. I could be more helpful with specifics about her location including distance from the ocean and the soil characteristics. The amount of land available for cultivation is also relevant as the value of tree crops and advisability of “forest gardening” (google Robert Hart) become increasingly pertinent. Feel free to send her my email address for more guidance. I’m retired and miss my online course.
BACK TO FAVAS: One of the data sheets I’ve downloaded rate pounds per acre N fixing at 71-220 for favas and 172-190 for field peas. My GUESS is that the wide range of N fixed by favas depends of soil phosphorus levels. Field peas are more likely to be grown commercially, where farmers routinely amend soil While most plant growth is limited by N availability, legume growth is limited by P availability. Field peas (soup peas), which tolerate drier conditions, may be a better choice for people with dry winters. The seed is also more cold tolerant. Both peas and favas (a species of vetch) take the same nitrogen-fixing inoculant. I feel that is worthwhile to inoculate legumes every time I plant them, even if, as is the case this fall, favas will follow peas in one of my beds.
I see that you use the term “lazy gardening” that Robert Kourik, another stellar west coast writer, put in the title of one of his books. In my view, intelligent gardening automatically becomes lazy gardening.
Well, I’ve not use favas as a green manure crop before, but your advice as convinced me, and I’ve got my seed and am ready to plop it into the ground as soon as the last of my fall crops are harvested. Thank you for that advice.
This was a wonderful article on growing fava beans. I am just getting into them and really appreciated the information.
Thank you for the great info!! Will be trying the sweet loraine this winter.
Just purchased some of the sweet lorane. I’m trying to build fertility in a plot of land which is mostly sandy out in Hendry County in South Florida. Not sure this will actually work there but happy to give it a try.
Definitely worth a try! Cover crops like fava beans are great for adding biomass to your soil. Let them build up over time and mulch your beds during the off season (with wood chips, alfalfa, or straw) to improve the soil structure each year.
I suggest one of the varieties of smooth seeded (not wrinkled) peas unless you are prepared to irrigate frequently. Even so, saving water is a major concern in Florida.
Hi there! A lot of articles say to use a garden soil inoculant containing rhizobium leguminosarum bacteria when sowing fava seeds for cover crops. Have you ever used this and noticed a big difference? Thx!
If you already have healthy soil full of microbes, the inoculant is unnecessary in my opinion. However if you’re sowing fava beans specifically as green manure and you want to ensure there will be enough nitrogen-fixing bacteria in the soil (or you’re trying to revive poor soil, or prep a virgin garden bed for planting), then inoculant is recommended.
Early to mid fall is best, but if the weather has been temperate, you can get away with seeding your fava beans later in the season. I’ve seeded my plants in winter when we’ve had unusually warm weather in SoCal. The only con to that is the lower angle of the sun in our garden, which slows their growth.
Where can I get fava bean seeds? I live in Marin County.
I get mine from Baker Creek Heirloom Seeds (rareseeds.com). They also have a brick-and-mortar store, the Petaluma Seed Bank in Petaluma. I highly recommend a visit!
How about pesticide? I tried to grow fava beans for two years, and each year the plants were covered with aphids. How to deal with it?
I occasionally use neem oil spray to control aphids, but find that aphids only appear at the end of the season when the plants are already stressed and starting to die back. If they’re attacking healthy plants, you might be underwatering or overwatering, or there may be another underlying cause like excessive nitrogen or lack of sun. If you’re using any kind of pesticide, it’s also possible the pesticide may have killed off beneficial insects that typically prey on aphids.
Question for Garden Betty or other….. How long between germination until flowering and pod production ? I am thinking of planting as a cover crop but cutting and disking under before pods are produced to gain all the nitrates produced and the organic mater as green fertilizer. thanks
Mature fava beans can be harvested in about 3 months, so I would guess they start flowering about halfway through that cycle. However, if you’re in a very cold climate, the plants continue to leaf out all fall and winter but don’t bloom until spring.
Right on — I’ll try this in the winter to fix nitrogen in my “medicinal herb” garden beds. We get fava beans in our CSA and they’re really tasty after all of the labor involved. We saute them in butter and garlic.
You can also eat fava bean pods whole — just throw them on a grill!
The top shoots are edible. I sauté them as I would pea leaves. I also harvest some if I need to thin the beans that I’ve planted.
They’re delicious! I write about that here: http://gardenbetty.com/2013/12/harvesting-and-pruning-the-leaves-and-flowers-from-your-fava-plant/
We planted our fava beans too deep this year, 6″!!!!!! Only 4 or 5 have grown a few inches in height out of 30 or 40 seeds. Will the rest grow or not? We live in central California if that helps any. I appreciate your time and help with this.
I’d say that if the majority of your seeds haven’t germinated after 10 days, they probably won’t at all.
Thanks for this — very interesting! Coudl you please tell me how long they will be productive for? I have lots in my southern hemisphere garden and they are giving us great beans, but they have crowded out/shaded everything else and I’m keen to cut them down in the next month.
Mine go all season, so I guess at least 4-5 months or so.
Put in a cover crop before winter to enrich soil. Planting Fava Beans as a Fall Cover Crop http://t.co/9lcOM9lFFr < TY for RT! @4bratz2luv
Start seeds in fall for harvest through winter/spring. Planting Fava Beans as a Fall Cover Crop http://t.co/RpoSYGdDAr < TY for RT! @Cubits
RT @theGardenBetty: Put in a cover crop before winter sets in to enrich your soil. Planting Fava Beans as a Fall Cover Crop http://t.co/9lc…
Put in a cover crop before winter sets in to enrich your soil. Planting Fava Beans as a Fall Cover Crop http://t.co/9lcOM9lFFr #gardenchat
RT @theGardenBetty: An edible crop that also nourishes the soil. Planting Fava Beans as a Fall Cover Crop http://t.co/Eu7oxN9q4k #gardencha…
An edible crop that also nourishes the soil. Planting Fava Beans as a Fall Cover Crop http://t.co/Eu7oxN9q4k #gardenchat #gardening
What a great idea! I am learning so many dimensions to gardening and was just going to toss some mulch on there but now I think i really need to plant fava beans. I love that it would be something potentially useful! Thank you!
Amy
rollermillfarms.blogspot.com
Great idea *also buys Chianti* MT @theGardenBetty: Don’t leave garden beds bare in winter: plant Fava Beans as cover http://t.co/P08rGWNzHw
Great tip! MT @theGardenBetty: Don’t leave your garden beds bare this winter: http://t.co/6U4X6mwY1C #gardenchat
Don’t leave your garden beds bare this winter: Planting Fava Beans as a Fall Cover Crop http://t.co/Qe2UECYyR0 #gardenchat #gardening
RT @theGardenBetty: Start the seeds in fall for harvest through winter and spring. Planting Fava Beans as a Fall Cover Crop http://t.co/Rpo…
Start the seeds in fall for harvest through winter and spring. Planting Fava Beans as a Fall Cover Crop http://t.co/RpoSYGdDAr #gardenchat
A natural fertilizer that’s edible to boot. Planting Fava Beans as a Fall Cover Crop http://t.co/Ec19wZ8w0D #gardenchat #gardening
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Planting Fava Beans as a Fall Cover Crop:
In the winter time, a couple of my garden beds get less sun and sta… http://t.co/svQhq1EMSC
Blogged on Garden Betty: Planting Fava Beans as a Fall Cover Crop http://t.co/NUxGAQgCQi