Planting peas as a nitrogen fixer

[wbmkk]

I was my local allotment shop today and they were selling packs of 200 Peas (Meteor) for 25p.

At that price .. It would have been cheeky to refuse them.

Now I like peas as much as everybody else, so will sow them.

However ! I was thinking (not like me at all !)

If I sow them early in seed cells now, then put them in the ground in March with some protection I could perhaps grow and harvest them, while cabages are planted in between rows. When the peas finish, I can leave their roots in place to provide some nitrogen.

I know they should really be planted in double rows, so I'll get a few more seeds and plant the cabbage between the double rows of peas.

This year will be my first allotment growing season, so I want to make a good impression ... on my wife, as well as neighbouring plot holders.

thanks !

[WendyC]

There whilst it is true legumes are able to fix nitrogen from the atmosphere there is some doubt as to whether any nitrogen is left in the soil once the peas have grown and set seed pods.
I generally sow them early February.

[Potstubsdustbins]

Its my belief that if you let the peas get to maturity then they have used the nitrogen.

Potty

[Penellype]

My understanding of this is somewhat different. I'm going to get on my hobby horse now (science/evolution) so feel free to disagree with me!

I think there is a general tendency to think of things like nitrogen fixing bacteria in legume root nodules as being there "for the benefit of the plant", in the same way that people say that for instance giraffes developed long necks so that they could eat leaves which are higher up. This is completely the wrong way round. The giraffes developed long necks because when there was a shortage of food the ones with long necks survived to breed and the ones with shorter necks were less likely to do so because they starved. Similarly peas and other legumes which formed a fortuitous symbiotic relationship (sorry for scientific jargon) with nitrogen fixing bacteria survived better because of the ready supply of nitrogen available. This does not mean that the nitrogen fixing bacteria were there purely for the benefit of the peas. They are there because the nodules on the pea roots give them things they can't make themsleves such as carbohydrates made by photosynthesis. Thats what the word "symbiosos" means - advantageous to both.

When the peas die the process stops and the nitrogen is released into the soil. If you harvest the pods and then remove the roots before the plants are completely dead you will also remove the nitrogen, therefore it is best to leave the roots in the soil.

For those interested there is more information here: Nitrogen fixation - Wikipedia, the free encyclopedia

[solway cropper]

The problem with the notion of giraffes with long necks surviving does not stand up to rational scrutiny. Female giraffes are 1 metre shorter than males and young ones even smaller so they couldn't possibly have reached the higher leaves. Giraffes have few, if any natural predators so they would have no problem getting all the food they wanted. Modern type giraffes start to appear in the fossil record about 2 million years ago and there is nothing before that so whatever reason there is for their long necks it has to be far more complex than merely reaching up for leaves.

Without wishing to disparage the generality of Darwin's ideas some were nothing more than conjecture and evolutionary biology has come a long way since then.

[Ananke]

I don't know anything about nitrogen fixing or giraffe necks but I thoroughly enjoyed reading those 2 posts ^^^

[bazzaboy]

I want to make a good impression ... on my wife, as well as neighbouring plot holders.

Ace thread! If I can be a trifle pedestrian amongst it, you won't make a good impression, wbmkk, if you plant your peas and nothing comes up....
You need to protect the seed from mice (very short necked mice are the worst!) they'll even individually excavate peas out of root-trainers. Presumably they can smell them once damp and swelling and Pea Soup must be a real treat in Mouse Land: once germinated and growing they don't seem to bother so much. So protect them at that early cell/module/gutturing stage (e.g. I use modules with clear lids held tightly in place with bungee clips) which should guarantee you the seedlings to plant out in the required sequence....

Then keep watered and the result will be mighty impressive!!

[Alison]

Mice aren't a problem for everyone, don't seem to be many round here so not everybody needs to protect against them. It's often best to try the simple methods too or you can be doing loads of extra work that is unnecessary in your area.


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[george356]

The problem with the notion of giraffes with long necks surviving does not stand up to rational scrutiny. Female giraffes are 1 metre shorter than males and young ones even smaller so they couldn't possibly have reached the higher leaves. Giraffes have few, if any natural predators so they would have no problem getting all the food they wanted. Modern type giraffes start to appear in the fossil record about 2 million years ago and there is nothing before that so whatever reason there is for their long necks it has to be far more complex than merely reaching up for leaves.

Without wishing to disparage the generality of Darwin's ideas some were nothing more than conjecture and evolutionary biology has come a long way since then.

The reason why giraffes have long necks is because their heads are so far away from their bodies

I'll get me coat

[BUFFS]

My understanding of this is somewhat different. I'm going to get on my hobby horse now (science/evolution) so feel free to disagree with me!

I think there is a general tendency to think of things like nitrogen fixing bacteria in legume root nodules as being there "for the benefit of the plant", in the same way that people say that for instance giraffes developed long necks so that they could eat leaves which are higher up. This is completely the wrong way round. The giraffes developed long necks because when there was a shortage of food the ones with long necks survived to breed and the ones with shorter necks were less likely to do so because they starved. Similarly peas and other legumes which formed a fortuitous symbiotic relationship (sorry for scientific jargon) with nitrogen fixing bacteria survived better because of the ready supply of nitrogen available. This does not mean that the nitrogen fixing bacteria were there purely for the benefit of the peas. They are there because the nodules on the pea roots give them things they can't make themsleves such as carbohydrates made by photosynthesis. Thats what the word "symbiosos" means - advantageous to both.

When the peas die the process stops and the nitrogen is released into the soil. If you harvest the pods and then remove the roots before the plants are completely dead you will also remove the nitrogen, therefore it is best to leave the roots in the soil.

For those interested there is more information here: Nitrogen fixation - Wikipedia, the free encyclopedia

I just dig mine into the soil after taking all the peas off and grow some salad crops there, something quick growing to use up whats left of the summer...