Hyacinth bean vine feeding nitrogen to sweet corn?

May 13, 2024 14:38:11

Unlike pole beans, hyacinth bean vine grows extremely well here. My sweet corn is about an inch high now and I'm thinking of interplanting with hyacinth bean vine (HBV). I have many questions about this and hope to hear from people who have worked with HBV:
Has anyone out there tried this? How did that work out?
Will the vine give the corn enough nitrogen so I won't have to add fertilizer?
Will the 10' vine overwhelm the ~6' corn stalks?
Is it okay to trim the vine and use it for mulch in the irrigation furrows?
Does planting many HBV seeds mean there will be more nitrogen for the corn or will the beans take nutrients that the corn needs?
Am I missing something in thinking that (since HBV covers the soil and climbs the plants) I could avoid planting squash in the garden thus keeping nutrients for the corn?
Will excessive bean vine disrupt the pollination process?
Any other suggestions?
Thank you in advance for your help!

May 13, 2024 15:54:44

i grow hyacinth bean, but have not tried interspersing it with corn. My uncle, who introduced me to the bean, grew both but kept them very much apart, since the bean vines tend to take over everything.
They're tasty (we eat the pods like snow peas) but they require lots of processing and are hard to keep up with.
I cant respond to most of your specific questions not having mixed them, but they should be fine for chop and drop. They are subject to the same pests that will go after pole beans, if you have them, but they are very hardy. I've never found corn to be super happy without external fertilizing, whether that be planted on top of fish or various teas, compost, top dressing, etc., no matter what I plant along with it.
They may smother the corn, but they take a while to get started (in my experience) so you might be okay if you're just starting now. If anything, keep up with them and trim them back. It is a VERY vigorous grower. I probably wouldn't plant more than a few just to start.
I cant imagine it would disrupt pollination, if anything it would attract pollinators.
It's a fun plant. I used to grow the green/white flower ones but recently got my hands on the purple variety. Also, rabbits enjoy eating the vines. Just avoid anyone eating the beans after they are out of the snow-pea-pod stage, as I think I remember reading that they have to be cooked once they mature into seeds. (not 100% sure on that)

May 13, 2024 17:21:46

Very helpful to hear your experience with the vine, Tereza: thank you for your thoughtful reply.
The purple flowers and pods are all that I have grown. I’ve never eaten the small pods so I look forward to trying that. I hear the purple flowers are edible but I want those vibrant purple pods so I don’t eat them (or the beans due to the energy required to remove the toxins).
I’ve saved seeds for about 8 years. Even the old seeds seem to sprout without effort or fertility and thrive in our full sun. The vine does not overwinter here in zone 7b so it is easier to manage than vetch when I prefer not to disturb the soil too much.
The corn patch is 20’ x 16’ which is enough for 4 rows of corn, 20’ long: about 140 plants with a spacious outer edge. After harvesting last year’s corn (I didn’t rotate due to space limitations), I composted the manure of 2 horses for a month (nearly 2 tons?) right in the corn patch. I let this pile compost for 6 months before raking it into the soil. I added Yum Yum mix (2-1-1) a few days before planting seed on May 1st. The goal is to use nitrogen fixing beans to get through the 90 day growing period without adding amendments to the original soil fertility.

May 14, 2024 06:10:35

Sounds like you have the makings of an excellent corn patch with all that aged manure.
This is a link to one of my favorite Brazilian food blogs, long defunct but still fabulous. There is a translation tool at the top, which is terrible but better than nothing. It will give you a bit of an idea about how they're enjoyed here- it's country food, that city people have often never seen, the equivalent of a snow pea in warmer places where snow peas would never, ever grow. https://come-se.blogspot.com/2010/07/orelha-de-padre-lab-lab-feijao-mangalo.html
The unripe pods here are called "priest ears", you prep them by taking off the string that runs around the edge (slightly more troublesome than top-and-tailing string beans, need to use a knife on every pod), then they're cooked like a green bean. It's not as common to eat the dried beans down where I live compared to up north where it's hotter, but I have eaten them and they're tasty. I understand they're a staple bean in Cape Verde and maybe Kenya?
Don't let the toxin talk worry you too much- from what I gather it's just the same thing as lima or kidney beans, you just need to boil the beans (whether they're soft or dried or even sprouted). Believe me, if you want to eat the dry bean you'll be boiling them for a while, as they take a long time to soften up (even in the pressure cooker)-- they don't call them stone beans in Cape Verde for nothing!
We eat a lot of beans here, and I love having yet another bean (like the cowpea) that I can grow with next to no effort if push comes to shove.

May 14, 2024 06:50:07

Hi Amy,
I have heard, but I don't know for certain... so please take this with a grain of salt.

But from what I have heard, nitrogen fixing plants do not generally release much (if any) nitrogen into the soil, until there is a die back of some sort. Either its the end of the season and the plant dies, or it is a perennial and it gets pruned. So, it might not provide much benefit while its growing. I think you would need to do the chop and drop... or grow the Hyacinth one year, and then put corn there the next year.

Is there someone more versed in nitrogen fixing plants that can confirm or deny this?

May 14, 2024 07:02:38

Tereza, I think you just solved the bean vine problem by mentioning cowpeas! Other than a small test patch of hyacinth bean, I’m switching to cowpeas (or black eyed peas as they’re called here) for the following reasons:
Although pinto beans are a New Mexico staple, black eyed peas are what the old-timers plant almost exclusively in my village on the outskirts of Albuquerque. There has to be a reason why they do this but I never thought to simply trust the practice. Pintos were a failure for me (other than putting a handful in the ground before planting trees to break up the soil below).
My biggest concern is that the bean vine will cover the corn silk and prevent the corn-tassel-pollen reaching the silk strands. I don’t want to lose the whole harvest due to bean vine interference with wind-pollination. Rather than take the risk, I’ll to a little experiment by planting a test hill of about 7-10 corn seeds and 3 hyacinth beans. For my special sweet corn patch, I’ll use the black eyed peas that are much shorter (2’ - 6’ tall).
Thank you for all your encouragement and ideas Tereza! I’ll use the bean vine to fix nitrogen in the berm where it will cover my fruit tree trimmings.

Matt, I too wonder if the beans will provide nitrogen as they grow. Will they take the vital corn nutrients to get established? I too hope some expert will provide a clue here. Thank you for bringing up the topic!

May 14, 2024 07:49:36

Matt said, But from what I have heard, nitrogen fixing plants do not generally release much (if any) nitrogen into the soil, until there is a die back of some sort.

This is also my understanding of nitrogen-fixing plants.

The way to use the nitrogen is to chop and drop the hyacinth bean vine and use it as a mulch as the nitrogen is in the leaves.

May 14, 2024 10:30:33

From Wikipedia's Root nodule

Plants that contribute to N2 fixation include the legume family – Fabaceae – with taxa such as kudzu, clovers, soybeans, alfalfa, lupines, peanuts, and rooibos [and hyacinth bean vine]. They contain symbiotic bacteria called rhizobia within the nodules, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants, and this helps to fertilize the soil.

Okay, I'm finally understanding the nitrogen fixation process with the help of Matt, Anne and Wikipedia. I used to think that the root nodules that attached themselves to the legumes exuded nitrogen into the soil for all the plants: wrong. Now I see that the legume is the host to the nitrogen fixing bacteria (rhyzobia) and the legume plant enjoys all the the gifted nitrogen. The only way for other plants like the corn to get that nitrogen is to let the plant matter decompose: die back releases the stored nitrogen!
Sometimes it takes a while to understand a concept but now I really get what's happening. Thank you Matt & Anne.

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