More Fava Bean Information:
🌷 Fava Bean Spring Planted Growing Guide
🍂 Fava Bean Fall Planted Growing Guide
🍽️ How to Prepare Fresh Fava Beans for Healthy Recipes
Cover crops like fava beans have revolutionized my gardening. They not only enrich the soil but also provide a natural mulch, reducing my need for chemical inputs.
I bet you wouldn’t say your garden soil is perfect.
On the contrary, most gardeners have a few qualms about their soil that they wish they could improve.
That’s where cover crops come in.
There are different cover crops for different soil needs. Some crops are better known for breaking disease cycles, while others are known for adding heaps of organic matter to compacted soil to make it more loamy over time.
I’ve seen the benefits of cover crops in my own garden. I love how they provide free mulch for my garden when they are cut back, and how they are supporting my heavy clay soil to be more workable.
As a bonus, cover crops are usually grown in fall and kept in place over winter into the early spring. This is an “off-season” opportunity to capture carbon in your soil. Good for your soil, good for the environment.
If you’re wanting to be sustainable, here’s the thing to remember: No herbicide is needed to kill back your cover crop.
Instead, cut back or crimp the crop. This will break the plant at the stem. Leave any plant residue on or in the soil.
Here’s how to terminate a cover crop with a fence post.
Alternatively, my method of choice is to trim it back to the soil with some clippers or scissors.
Now that you’re caught up on the benefits of cover crops, learn why I’m obsessed with fava beans.
Soil Microbes + Fava Beans = ❤️
Fava beans are BFFs with certain microbes in the soil that transform nitrogen in the atmosphere into something that the plants can use.
They literally make fertilizer out of thin air! That’s why it’s called “fixation” - microbes “fix” or “correct” the atmospheric nitrogen into something that is available to plants as a nutrient.
Learn more about how no-till farming supports nitrogen fixation
Just how much nitrogen do fava beans contribute to the soil?
A study published in 2023 showcased that a cover crop of fava beans can offer up to 133 kg of Nitrogen per hectare (or around 118 lbs per acre) to the next crop.
→ Bonus: Increased Yields: The same study found that corn - a plant that needs a lot of nitrogen as it gets established - planted after a fava bean cover crop provided a 28% increase in yield compared to corn grown without a cover crop.
How to know if nitrogen is actually being fixed?
What’s even cooler is that you can actually see the nitrogen.
While I want to keep as many roots in the ground as possible, sometimes curiosity gets the best of me and I will pull up a fava bean plant or two. If you do this and see little white nodules on the root systems, that’s a sign that nitrogen fixation is happening!
The first time I actually saw these nodules, it was a pretty exciting moment.
Cutting back fava beans and leaving the roots behind means that any residual nitrogen nodules are now available for the next crop planted in this area.
In this way, nitrogen fixation not only provides enough nutrients for the fava beans to thrive, but offers any “left-overs” to the next crop to benefit from, too.
Phosphorus Availability
It should also be noted that the nitrogen fixation process utilizes phosphorus in and of itself. However, if phosphorus is readily available in the soil, fava beans can support surrounding plants to access this nutrient easier.
As this study notes, fava bean roots release chemicals that dissolve phosphorus so that other plants growing in the area can utilize it.
Reduced erosion
Fava beans planted over winter have the benefit of preventing erosion during an otherwise vulnerable time.
Less soil erosion helps maintain the health and vitality of the soil. This leads to better crops and less need for fertilizers.
In 2023, researchers at the American Farmland Trust worked with computer models to calculate that fava beans as a cover crop in almond orchards reduced soil loss by 61%.
This will help keep farms productive over the long term, especially as climate change brings about heavier rains and prolonged droughts, which can contribute to erosion.
For my rainy winter climate, this is a huge asset. The roots of the fava beans hold the soil in place so that it’s not lost to wind and heavy rains.
Reduced compaction
The roots of fava beans have the ability to transform compacted soil into smaller pieces.
This makes it easier for water to be taken into the soil, which can prevent both flooding and drought (CSU Chico through SARE).
Think of it like trying to pour water onto a solid slab of concrete. The water will roll right off. However, if instead you were to pour water over a pebble-covered path, water would be able to seep through and get absorbed into the ground.
We want to have space within the structure of the soil for the water to permeate.
In my garden, which has heavy clay soil, fava beans really help to improve my soil’s tilth.
Between their greenery and root systems, fava beans can contribute between 20-40 tons of biomass per acre, according to the USDA.
Each year, my garden thrives due to the organic (and essentially free) mulch that fava bean plant residues provide. It’s an awesome way to get materials for chop-and-drop in my organic garden. I just scatter the plant material around any spot with bare soil.
California State University in Chico found the “Bell Bean” variety to be top performing in terms of the amount of plant matter that can be given back to the soil.
Resource competition can be a good thing
Weeds are a disadvantage to our crops due to their ability to compete for resources in the soil. Fava beans, however, actually flip the script with an Uno reverse card.
According to a narrative review from 2023, fava beans can shade out weeds, win in the fight for nutrients, and make use of the water.
This all adds up to reduce the amount of weeds that come up in the soil.
I really notice this in my garden come springtime. Where there were fava beans or other cover crops planted, the amount of weeding I need to do is drastically less than areas with unplanted soil.
Fall Growing
As a cover crop, fava beans are usually fall-sown anytime before your first frost. This can be from September through November, depending on your climate.
See my guide on fall planting fava beans for more suggestions!
Late Winter/Early Spring
Fava beans can also serve as a cover crop when sown in late winter/early spring. In most climates, these hardy beans can be planted by mid-March.
In my experience, I’ve noticed that even fava beans that seem to die back in cold temperatures will grow back from the root base.
With a 80-90 day window to maturity, another crop can be grown in the same spot before the end of the season.
As mentioned by Fatemeh Etemadi at UMass Amherst through SARE, the earlier you plant your beans in the spring, the less likely they will be to succumb to heat-induced disease. Early plantings also gives you the advantage of larger yields.
I’ve seen this in my own garden just this past year. Fava beans planted in June got diseased and didn’t yield nearly as well as the crop I planted in February.
Prep Tips:
How Much Seed to Buy?
Soil + Seed Prep
Plant Spacing
→ Tip: OSU recommends slightly oversowing your fava beans when fall planting to make up for any plants that may die off in cold temperatures.
Sow + Water
I prefer to sow fava beans directly before a good rain event. Of course, you can water your seeded beds with drip irrigation or a regular hose. In either case, be sure to water your newly sown seeds in well.
→ Reminder: Keeping the soil evenly moist after sowing ensures better seed sprouting
Sources: PW Singleton et. al University of Hawaii, USDA, Fatemeh Etemadi at UMass Amherst through SARE, Experimental Farm Network, OSU, Alberta Pulse, True Leaf Market
Source: Agronomy
In 2023, researchers at the American Farmland Trust worked with computer models to look at how farming can both support the environment and adapt to upcoming changes.
Fava beans can help mitigate climate change due to their ability to store carbon in the soil.
In California, they found that fava beans stored twice as much carbon compared to another cover crop, triticale.
Their models show that grapes paired with fava beans as a cover stored 8 times more carbon than grapes without a crop integrated with them.
For me, incorporating fava beans as a cover crop has been rewarding and overall fairly easy. Their myriad benefits—from reducing erosion to suppressing weeds—makes them a must-try for any gardener looking to enhance soil health sustainably.
If you're considering adding a cover crop to your garden, I wholeheartedly recommend giving fava beans a shot.
Their contribution to the ecosystem, paired with their ability to regenerate and thrive in various conditions, makes them a valuable ally in any gardener's toolkit. Make the most of your garden's off-season to nourish and prepare your soil for a bountiful growing season ahead. Trust me, your garden will thank you!
