[kirpi]

I have a blank space where next year's potatoes are going to go and I want an overwintering green manure to sow there.

I don't think potatoes are all that hungry for nitrogen and if they get too much you can end up with loads of foliage compared to spuds.

so - would you so a legume here or not? I'm not keen on mustard as we have club root around although I know it is good against eelworm cysts (but is that after the potot harvest and not before as such?).

Oh - decisions, decisions ...


Title typo edited for future search purposes.

[crh75]

Can't help sorry.  I always cover the potato bed in manure over winter so don't use a green manure on that bed. 

[Salmo]

Legumes are unlikely to fix nitrogen unless left until at least late April/May before digging in. I presume that you will want to dig before that. Nevertheless field beans or tares will give good bulk.

The alternative to mustard for a quick crop is phacelia. This will cover the ground to stop weeds and is easy to dig in. It usually survives the Winter but will probably be quite tatty by the Spring.

[kirpi]

Thanks Salmo - some things to think about there. It sounds like legumes would be a viable choice as I won't dig the bed over because the bed is loose enough to allow me to just plug the seed potatoes in and they will grow up through the legumes in spring and eventually smother them - or if not, I will pull and drop the legumes later into the year if the potatoes are struggling.

[Kristen]

I don't think potatoes are all that hungry for nitrogen and if they get too much you can end up with loads of foliage compared to spuds.

I found a PDF on the Potato Council's website about Green Manure. It wasn't very specific to potato growing and was mostly concerned with measuring the amount of Nitrogen that was locked up, and then released, by the process (and doing a cost-benefit equation comparing the cost of the seed and application thereof to the cost of Nitrogen fertiliser in the Spring and any extra cost of tilling (to remove weeds in spring etc.)

That said, one could form the viewpoint that the Nitrogen was seen to be beneficial, at least in the early stages of plant development of the Spuds. But it didn't explicitly say that ...

http://www.potato.org.uk/sites/default/files/%5Bcurrent-page%3Aarg%3A%3F%5D/Green%20manures.pdf

[Salmo]

I don't think potatoes are all that hungry for nitrogen and if they get too much you can end up with loads of foliage compared to spuds.

I found a PDF on the Potato Council's website about Green Manure. It wasn't very specific to potato growing and was mostly concerned with measuring the amount of Nitrogen that was locked up, and then released, by the process (and doing a cost-benefit equation comparing the cost of the seed and application thereof to the cost of Nitrogen fertiliser in the Spring and any extra cost of tilling (to remove weeds in spring etc.)

That said, one could form the viewpoint that the Nitrogen was seen to be beneficial, at least in the early stages of plant development of the Spuds. But it didn't explicitly say that ...

http://www.potato.org.uk/sites/default/files/%5Bcurrent-page%3Aarg%3A%3F%5D/Green%20manures.pdf

Potatoes need nitrogen in the early stages. Never top dress later as it will only produce excessive tops.

[Salmo]

Thanks Salmo - some things to think about there. It sounds like legumes would be a viable choice as I won't dig the bed over because the bed is loose enough to allow me to just plug the seed potatoes in and they will grow up through the legumes in spring and eventually smother them - or if not, I will pull and drop the legumes later into the year if the potatoes are struggling.

Perhaps you are missing the point of green manure. As the plants grow they use up spare nutrients and bring more up from deep down. If you dig them in they decompose and the nutrients are released to become available for your crop. The decomposing material also helps to retain moisture.

If you have seen field beans or tares growing you will know that dibbing potatoes in amongst them is not a sensible option. By the time you plant potatoes they will be 2ft high and growing fast. You might get away with it if you strimmed or ran a mower over first to make a mulch.

[kirpi]

Yes, sorry my post didn't explain that I plan to level the green manure crop and then dib in the seed potatoes so the legume roots are still in the topsoil releasing their nitrogen and the top growth forms a feeding and weed suppressing mulch and light supressing in the later stages as the spuds form.