Envy Soybean

Glycine max
Sow depth1/4 to 1 inch, depending on whom you trust (1/2 inch seems a safe bet)
Emergence7-14 days
Temperature20-30 degrees Celsius
LightFull sun. Less than 14 hours at peak.
SoilLoamy soil
Height2 feet
PollinationSelf-fertile (which doesn't mean they self-fertilize, there needs to be a breeze or a Q-tip or something involved sometimes, but mine seem to have quite a good time all by themselves, y'know, never having seen a flower on them before)
Maturity75 days. (Probably photosensitive; flowers when days get shorter. I say probably because there's a dearth of information about which varieties aren't photosensitive.)
HarvestHarvest all green pods on a plant when seeds flesh out and almost touch. Any yellow on the pod and it's past harvesting point for edamame-eating purposes; keep on plant until pod fully dries and collect seed for next planting.
Culinary UseBlanch and salt as edamame, or use beans in salad, stir fry, chili, or soup.
ProblemsSoybean rust, bacterial pustule, downy mildew, brown spot, frogeye leaf spot, bacterial blight; beanfly, pod borer, stink bug, thrips

No info whatsoever about growing indoors (of course). Apparently the "vegetable soybean" varieties have only recently become popular in the states (in the past decade, maybe), so a lot of available information for backyard gardeners says stuff like "Try this shocking new plant, you'd never have thought it is good to eat, ZOMG you'll love it!"

Fixes atmospheric nitrogen and enriches soil. Root nodules form with Rhizobium japonicum bacterium. I'm pretty certain that Rhizobium species are common soil microbes, and they are symbiotic with leguminous plants. Seeds are often inoculated with the specific nitrogen-fixing species that associates with whatever bean is being grown prior to sowing to ensure a good chance of root nodule formation. Nitrogen is fixed in root nodules--fixing nitrogen just means taking it from the air as a gas and turning it into a form that plants can use. Most plants can't do this, but beans can, with the help of Rhizobium.

So, to summarize: maintain an average room temperature, pretty much; keep soil moist, but not soaked; allow natural increase/decrease in amount of sunlight for best production (just in case my variety is photosensitive); test soil pH; use better soil. I think I should rename my blog to "Holy Cow, I Didn't Even Look At The Seven 40-Pound Bags Of Soil I Put In Here." I don't know if it's topsoil, garden soil, potting soil--well, I am almost certain it's not potting soil. I was in a daze of euphoric garden-box construction. I'll fix it, with fertilizer and compost and stuff!

Now. On to the drama.

At first, I screamed, "Oh no! Soybean rust! How unlucky could this indoor gardener beeeee????"

I fell to the ground, I sobbed, I raged, and eventually I googled. (Click above to "See?" better.)

It's not soybean rust, Phakopsora pachyrhizi. (I worked with this fungal plant pathogen during an internship in Germany. It's pretty horrible! For plants, that is.) But I think what my soybeans have is just "bacterial pustule" as opposed to some of the other likely candidates, mostly due to the lack of leaf deformity and the general health of the plant, along with other telling characteristics about how the infection presents itself on the plants. Just to give a little frame of reference on how to go about figuring out what a soybean plant might be infected with, there are 71 listed soybean diseases on Wikipedia. Most of them don't have nearly similar symptoms to what mine exhibit, but that is a pretty hefty list! But anyway, let's start with a bit of locative facts. I have three soybean plants: the single one and the couple, who live twisty-tied to the stick.

Weeks and weeks ago, I noticed the raised, slightly lighter green bumps on most of the soybean leaves, before even finishing the planter box (looong time ago). Click on the picture above to see the raised, light green bumps in better detail.

The loner, who grew the first two soybean pods, started losing its trifoliate leaves, leaflet by leaflet, from the oldest leaf up to the newest. These leaves had become generally chlorotic (yellow) prior to defoliation, and it was a pretty fast process. I didn't know what the problem was, but the onset of defoliation corresponded with the intense-light incident, so I took a hit to my ego and assumed it was my intender care and the light shock that caused the problems.

Once I started growing worried about that specific plant (which didn't show the same exact symptom progression as the other two), I also started noticing that some of the raised bumps on the others (which I had just assumed were natural to the plant, due to the uniformity and because the bumps had pretty much always been there) had started becoming brown, the areas surrounding the brown bits turning yellow. Not all mind you, just some.

But some is enough. Such infections on plants can reduce crop yields significantly, from 20% all the way to 100% (probably because the plants die). This worry drove me to do more research on the plants that I am growing, so I know what they look like when they're healthy, when they're sick, and when they're about to drop a huge load of fruit on me.

But the soybeans, back to them. Or rather, back to what is ailing them. Bacterial pustule's causative microbe is Xanthomonas axonopodis pv. glycines. ("pv." just stands for "pathovar," which means the variety of this bacterial species that infects soybean and other legumes. A lot of pathovars are just the same species of microbe found in different plants--like dogs. Same species, but each variety looks and acts differently. I'm glad they have the pv. notation here, because with Giardia, all the pathovars, basically, were named their own species: Giardia canis for isolates obtained from dogs, Giardia bovis for cattle, Giardia equii for horses, and so on, and so on. Most, I believe, are just plain ol' Giardia lamblia, which is also called Giardia intestinalis or Giardia duodenalis. It doesn't really matter what you call them, I guess--if you have an infection and start exhibiting symptoms, the name won't mean much to you, you'll just want to be left alone with a bathroom, a mound of toilet paper, and a good book.)

For those who care or for those to whom this will mean something, X. axonopodis is a gram-negative rod. Some species of Xanthomonas can degrade hydrocarbons (I won't get into the research, but during university, I used a Xanthomonas species as a positive control for hydrocarbon degradation--or, I would have, but it was extremely difficult to grow). X. axonopodis can live in soil, but it is (clearly) a plant pathogen that affects a broad range of plants, and so it could have been already present in the soil that I purchased and spread to the plants during germination or watering. Or, even, the seeds could have been infected. So many possibilities, it's crazy...

A severe X. axonopodis infection can cause defoliation. But I guess it depends on what you consider to be severe--the sources I found don't give such information. So it seems as if the lone wolf got the worst of it so far, probably because it had't yet started lateral growth prior to deciding to put energy into reproduction, thereby reducing its nutrient resources and its ability to make energy (fewer leaves, less photosynthesis, less energy, less able to survive an infection). Mostly humans can fight off illnesses (we have drugs!), and plants can too, but if they don't stop expending resources (such as fruit production), I think it's harder for them to survive an infection. And they can't verbally explain the symptoms they feel before their caretaker notices them--by the time they're noticeable, well, sometimes it's fighting an uphill battle.

I have been pinching leaves off to try to prevent the spread of whatever it is. The new leaves seem to have less symptoms, so maybe we're good.

Hopefully the plants will survive and thrive. I'll worry about pests if they come, but other than household-type pests (fungus gnats, thrips, whitefly, or some of the bacterial and fungal infections), I think I'll be fine.

Post Scriptum: Photos were taken on 8 April. The plants, now, are mostly defoliated from pinching. The duo have lateral growth--little leaves growing from the nodes. The singlet plant is thinking about growing leaves, but at the moment it's a leafless twig with a single bean pod on it (the second one fell off).

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4 Responses to Envy Soybean

  1. Man this is some good information. I want to get some soybean production going on here soon. There are so many uses for soybean, I think we have only just touched the surface on what this bean could offer.

  2. How can you be sure that your seed source is safe from genetic modification?
    Or does that not matter to you?

  3. Jo,

    In my "Seeds Say What?" post, I indicate the suppliers of my seeds. Most of them are certified organic (which costs $$ for the producer to label as such), and the others are at least heirloom varieties grown organically, if not certified.

    But, for me, I don't really care about whether a seed is genetically modified. When I was in high school, it was my dream to become a genetic engineer. But then I got bored of working in a lab.

    It isn't so much adding/deleting/modifying genetic functionality of a plant that bugs me... It's the harsh, overly-used chemicals and crazy growing practices they are subjected to when grown for the mass market. I don't care what kind of plant it is, but I want it to be grown organically (whether paid-to-be-labeled-as-certified or not).

    You can totally grow organic produce that is genetically modified. And I'm cool with that. But none of my seeds are genetically modified, so far as I know. (I would assume the beans, potato, chickpeas, and lentils are also not genetically modified, 'cause I bought 'em at an organic food store, but you never really do know.)

  4. You disappoint me.
    GM is letting the genie out of the bottle. I hope you change your mind one day soon.



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