I decided to try growing Soybeans in the UK last year after reading that potatoes grown following a crop of soybeans were less susceptible to potato scab, which is a problem that I have here. My Polyculture Update in February showed a picture of the small haul of soybeans that I harvested from six plants, that escaped the ravages of rabbits, pigeons, and chickens. I have soaked and germinated these beans, and they have now been sown. However they are part of an experiment which is in turn part of my Vegetable/Grain food production experiment. The short answer for anybody trying to work out if it’s worth Growing Soybeans in the UK is YES. I did it, but there are some challenges, which I’ll discuss below.
I soaked the soybeans in warm water overnight, and then put them into a tray with damp kitchen roll in the bottom. Germination of my own seed was excellent, with very few beans not producing roots. I had left the pods on the plants until they were really brown and dry, which made sure that they were fully ripe. Even so, I was surprised at how well they did. The picture below shows one of four trays of soybean seedlings that are currently ‘living’ in my greenhouse.
Fertility was restricted in the potting mix by incorporating plenty of sand and grit. This is to promote the growth of the Nitrogen fixing bacteria on the roots. If there is plenty of free nItrogen in the soil the plant doesn’t need the bacteria, so root nodulation is low.
Growing Soybeans in the UK without Rhizobia
One of the problems that I foresaw with growing soybeans in the UK was that our soils do not have the correct strains of Nitrogen fixing bacteria (Rhizobia). I bought a small amount of innoculant from a seed company in the USA, however when it got here, the use by date was less than 12 months away. In other words only good for one season. The innoculant produced good colonisation of the soybean roots, and I had plenty left over, so I saved some to see if the use by date could be ignored. I also grew six soybean plants in tubs. This was to allow me to save the compost, to see if I could use it to innoculate this year’s batch of plants. These six plants are the only ones that I was able to harvest beans from. (Note that once the right Rhizobium strains are present in the soil, they should be able to colonise the roots of soybeans without the use of an innoculant).
Soybean Rhizobia Experiment
I wanted to test two things;
- Would the commercial innoculant work past the sell by date?
- Would using compost in which soybeans with rhizobia had been grown be suitable as a DIY innoculant?
What I haven’t tested yet is whether there are any native strains of rhizobia which could colonise soy roots. I do have some commercial soybean seed left, so may try it just to see what happens.
In order to get answers to the two questions I have simply grown my germinated soybeans in two ways. One has had last year’s commercial innoculant sprinkled in the root zone, the other has had the top inch or so of each module topped up using compost from the two tubs that grew soybeans last year. It will be a early June before these beans are planted out. This will be the ideal time to check for colonisation of the roots.
I also intend to grow some of these plants in containers again, in order to maintain production of the soybean rhizobia, providing that the method works.
The picture below shows three trays of Rootrainers with soybeans in. There’s also a baking bean (bush).
Other Potential Problems
Just about everything that could eat the Soybeans last year, did. When I put cages over the plants to keep the rabbits out, the pigeons ate everything that grew out of the top. Luckily I spotted my chickens eating the young pods and lower leaves of the container grown plants. I was able to protect the soybeans with some rabbit mesh, which enabled me to produce some seed of my own. This pest problem is not going to be just for growing soybeans in the UK. I’m sure that the same would apply anywhere, but on a field scale the losses would be less noticeable. Protecting the soybeans throws up some interesting possibilities. They could be grown amongst soft fruit plants in a cage, or with brassicas under nets. Both crops would benefit from the small amount of Nitrogen that the soybeans would fix. I’m going to grow them in a polytunnel this year, and then rotate a crop through the whole vegetable growing area. I suspect that I will locate them with brassicas under nets, ahead of potatoes in rotation. That way the soybeans will be protected from pests, and if there is a reduced incidence of scab as a result of the soybeans, that will be a bonus.
I will post pictures of the results of this latest experiment when the soybeans are planted out.