Growing Potatoes in Clover and Seaweed


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I'm trying to figure out how to 'feed' my soil for the next crop whilst the first crop is still growing. I've got several 1m square raised beds.

I want to add some sulphur chips to the beds to help fend of scab. Then I plan to plant my leftover clover plugs to act as cover crop over winter.

In late March I'll plant my potatoes through the clover, leaving it in place as a mulch.

As the leaves of the potatoes grow up I'm guessing they'll shade out and kill off the clover. Rather than earthing up with soil I was thinking of using seaweed.

At harvest time (late August) the rotted down seaweed and clover will get mixed into the soil. Leaving the soil in good condition for planting.....what?
 
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Oliver, my line of thinking here is to create soil for the next crop whilst growing the current crop.

So, remember we talked about putting rotten wood, manure etc into containers in Autumn then growing winter pansies etc in a thin top layer of compost? That (in theory) should have produced a lovely potting compost for beans and squash when the flowers come out.

White clover is obviously a good cover crop for bare soil, so it makes sense to use that given that clover WANTS to grow in my garden. But rather than till it in, why not leave it in situ to act as a mulch? I guessed that potatoes would be more than capable of competing with the clover and the clover would reduce the need for watering and earthing up. I found an article where someone has tried this successfully.


Then I got to thinking how I could further improve the soil whilst the potatoes are growing. I know potatoes take a lot of nutrients so why not feed the soil whilst the potatoes are growing? I've read that commercial potato growers in my area put seaweed onto their fields. I have easy access to seaweed so if I use seaweed to 'earth up' when the clover dies off due to lack of light it'll help the potatoes and provide food for the next crop.

So...
  • I've added sulphur chips prior to planting potatoes to reduce risk of scab (lowering ph)
  • I've tilled in (whilst harvesting potatoes) clover
  • I've tilled in rotted down seaweed.
So intuitively it sounds like I've got some good soil for the next crop. But then it all gets a bit hazy because I'm not sure whether it's 'complete' - does anything else need adding? @Meadowlark - you're the rotation/covercrop guy - do you have any insight? Keep in mind that I don't have a lot of land - I'm working with small raised beds.
 
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Here is the nutrition of a single potato to give some ideal of what a potato tuber pulls out of the ground. This does not include the vines and leaves. These are weight percentages.

Protein converted to Nitrogen: 0.325%
Phosphorus: 0.057%
Potassium: 0.421%
Calcium: 0.012%
Magnesium: 0.023%
Sodium: 0.006%
Iron: 0.00079%
Zinc: 0.00030%
Copper: 0.00011%
Manganese: 0.00016%

--------------------------------------------------------------------

So according to them a medium sized potato weighs about 213 grams.

Nitrogen: 213g * 0.00325 = 0.69225 g of Nitrogen per potato * 8 potatoes per plant = 5.538 g of Nitrogen per plant.
Phosphorus: 213g * 0.00057 = 0.12141 g of Phosphorus per potato * 8 potatoes per plant = 0.97128 g of Phosphorus per plant.
Potassium: 213g * 0.00421 = 0.89673 g of Potassium per potato * 8 potatoes per plant = 7.17384 g of Potassium per plant.
Calcium: 213g * 0.00012 = 0.02556 g of Calcium per potato * 8 potatoes per plant = 0.20448 g of Calcium per plant.
Magnesium: 213g * 0.00023 = 0.04899 g of Magnesium per potato * 8 potatoes per plant = 0.39192 g of Magnesium per plant.

I'm kinda surpised to see such a low phoshorus requirement and that the nitrogen is that high.

If seaweeds NPK is 2.2 : 0.4 : 3.5, then that seems to be the perfect fertilizer for potatoes as far as the npk ratio goes but we aren't calculating for the vines and leaves because I have no information on those.
 
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Oliver, my line of thinking here is to create soil for the next crop whilst growing the current crop.

So, remember we talked about putting rotten wood, manure etc into containers in Autumn then growing winter pansies etc in a thin top layer of compost? That (in theory) should have produced a lovely potting compost for beans and squash when the flowers come out.

White clover is obviously a good cover crop for bare soil, so it makes sense to use that given that clover WANTS to grow in my garden. But rather than till it in, why not leave it in situ to act as a mulch? I guessed that potatoes would be more than capable of competing with the clover and the clover would reduce the need for watering and earthing up. I found an article where someone has tried this successfully.


Then I got to thinking how I could further improve the soil whilst the potatoes are growing. I know potatoes take a lot of nutrients so why not feed the soil whilst the potatoes are growing? I've read that commercial potato growers in my area put seaweed onto their fields. I have easy access to seaweed so if I use seaweed to 'earth up' when the clover dies off due to lack of light it'll help the potatoes and provide food for the next crop.

So...
  • I've added sulphur chips prior to planting potatoes to reduce risk of scab (lowering ph)
  • I've tilled in (whilst harvesting potatoes) clover
  • I've tilled in rotted down seaweed.
So intuitively it sounds like I've got some good soil for the next crop. But then it all gets a bit hazy because I'm not sure whether it's 'complete' - does anything else need adding? @Meadowlark - you're the rotation/covercrop guy - do you have any insight? Keep in mind that I don't have a lot of land - I'm working with small raised beds.
I tried that this season. I loved the fact that ground backsplash was noticeably reduced by the secondary plants. And I did not buy clover. Just let it grow. Many plants are simply resistant to fungi that attack tomato for example. Brilliant function in that regard. I was straining my shoulders patting myself on the back. But at maturity, complications set in. Low level moisture, increase in insect pressure since hiding was enhanced, and like weeds, resources were consumed by non-target plants . Root competition. Next year I am going back to the fluffy mulch. Or straw. Depends on what is available these days. Were I to use clover as you seek to do, I would suggest letting it mature to seed, even across a season, before digging or planting. You need to help the clover establish, even if you are lucky enough to have it spread. Even then it won't feed much, but there are cooling and disease control benefits here at 33 lat.

As to seaweed, it can be too expensive. If it is cheap then by all means go for it. It's just that it is best used in a certain way when it is expensive, that being as a source of growth regulating phyto-hormones and trace minerals and micro nutrients. The hormones are why it seems magical. We are well inland here and more likely to get algae problems from the freshwater plants that might be used locally. The golf courses suffer that fate when they pump stream water for example.
 
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I tried that this season. I loved the fact that ground backsplash was noticeably reduced by the secondary plants. And I did not buy clover. Just let it grow. Many plants are simply resistant to fungi that attack tomato for example. Brilliant function in that regard. I was straining my shoulders patting myself on the back. But at maturity, complications set in. Low level moisture, increase in insect pressure since hiding was enhanced, and like weeds, resources were consumed by non-target plants . Root competition. Next year I am going back to the fluffy mulch. Or straw. Depends on what is available these days. Were I to use clover as you seek to do, I would suggest letting it mature to seed, even across a season, before digging or planting. You need to help the clover establish, even if you are lucky enough to have it spread. Even then it won't feed much, but there are cooling and disease control benefits here at 33 lat.

As to seaweed, it can be too expensive. If it is cheap then by all means go for it. It's just that it is best used in a certain way when it is expensive, that being as a source of growth regulating phyto-hormones and trace minerals and micro nutrients. The hormones are why it seems magical. We are well inland here and more likely to get algae problems from the freshwater plants that might be used locally. The golf courses suffer that fate when they pump stream water for example.
Thanks for that. Good to know. I'm close to a beach so seaweed is free. I might try clover in one small bed just in case it's different in my climate.
 
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Here is the nutrition of a single potato to give some ideal of what a potato tuber pulls out of the ground. This does not include the vines and leaves. These are weight percentages.

Protein converted to Nitrogen: 0.325%
Phosphorus: 0.057%
Potassium: 0.421%
Calcium: 0.012%
Magnesium: 0.023%
Sodium: 0.006%
Iron: 0.00079%
Zinc: 0.00030%
Copper: 0.00011%
Manganese: 0.00016%

--------------------------------------------------------------------

So according to them a medium sized potato weighs about 213 grams.

Nitrogen: 213g * 0.00325 = 0.69225 g of Nitrogen per potato * 8 potatoes per plant = 5.538 g of Nitrogen per plant.
Phosphorus: 213g * 0.00057 = 0.12141 g of Phosphorus per potato * 8 potatoes per plant = 0.97128 g of Phosphorus per plant.
Potassium: 213g * 0.00421 = 0.89673 g of Potassium per potato * 8 potatoes per plant = 7.17384 g of Potassium per plant.
Calcium: 213g * 0.00012 = 0.02556 g of Calcium per potato * 8 potatoes per plant = 0.20448 g of Calcium per plant.
Magnesium: 213g * 0.00023 = 0.04899 g of Magnesium per potato * 8 potatoes per plant = 0.39192 g of Magnesium per plant.

I'm kinda surpised to see such a low phoshorus requirement and that the nitrogen is that high.

If seaweeds NPK is 2.2 : 0.4 : 3.5, then that seems to be the perfect fertilizer for potatoes as far as the npk ratio goes but we aren't calculating for the vines and leaves because I have no information on those.
Thank you! My typical routine is to put a couple of inches of garden compost on all my beds in December so that should take care of what the vines ad leaves have taken out. So I think I have a plan - drop the clover and stick to seaweed!
 
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Thanks for that. Good to know. I'm close to a beach so seaweed is free. I might try clover in one small bed just in case it's different in my climate.
You may have salt issues. It would be interesting to know. I found out that plants requiring boron often have a history that indicates they developed near oceans. Googling boron loving plants or what boron is used to fertilize may open the back door to lists and successful planting of unexpected varieties.
 
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A while back I read in passing that a commercial potato grower in the West of Scotland (my area) collected seaweed from the local beach and spread them on their potato fields. That's what got me looking further into this.

I found this:

" Potatoes are particularly fond of seaweed. The population explosion on Ireland's West coast before the famine was pretty much based on the link between potatoes and seaweed where soils were 'built' over generations using seaweed, sand and manure. I have seen potato plants growing in piles of seaweed alone and still produce very good yields"


I've found articles claiming that people successfully grow potatoes in nothing but seaweed.

I've used seaweed in my compost heap and I've always washed it first, but I have read that it doesn't absorb much salt so really there's no need to wash it. I think I'll keep washing though just to be safe.

Apparently seaweed is slightly alkaline. I had a bit of scab last year so part of my strategy was to keep ph levels low. Yet if potatoes do so well in seaweed I have to rethink that.

BTW if you google "clover living mulch' you'll find a lot of people claim success with this. I found some studies by farmers. But nothing specifically for potatoes though. I have a mini food forest so I think I'll see how clover works there.
 
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Here is the nutrition of a single potato to give some ideal of what a potato tuber pulls out of the ground. This does not include the vines and leaves. These are weight percentages.

Protein converted to Nitrogen: 0.325%
Phosphorus: 0.057%
Potassium: 0.421%
Calcium: 0.012%
Magnesium: 0.023%
Sodium: 0.006%
Iron: 0.00079%
Zinc: 0.00030%
Copper: 0.00011%
Manganese: 0.00016%

--------------------------------------------------------------------

So according to them a medium sized potato weighs about 213 grams.

Nitrogen: 213g * 0.00325 = 0.69225 g of Nitrogen per potato * 8 potatoes per plant = 5.538 g of Nitrogen per plant.
Phosphorus: 213g * 0.00057 = 0.12141 g of Phosphorus per potato * 8 potatoes per plant = 0.97128 g of Phosphorus per plant.
Potassium: 213g * 0.00421 = 0.89673 g of Potassium per potato * 8 potatoes per plant = 7.17384 g of Potassium per plant.
Calcium: 213g * 0.00012 = 0.02556 g of Calcium per potato * 8 potatoes per plant = 0.20448 g of Calcium per plant.
Magnesium: 213g * 0.00023 = 0.04899 g of Magnesium per potato * 8 potatoes per plant = 0.39192 g of Magnesium per plant.

I'm kinda surpised to see such a low phoshorus requirement and that the nitrogen is that high.

If seaweeds NPK is 2.2 : 0.4 : 3.5, then that seems to be the perfect fertilizer for potatoes as far as the npk ratio goes but we aren't calculating for the vines and leaves because I have no information on those.
You have to remember that potatoes are not root veg; they are tubers which grow on stolons from the stem.
 
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You may have salt issues. It would be interesting to know. I found out that plants requiring boron often have a history that indicates they developed near oceans. Googling boron loving plants or what boron is used to fertilize may open the back door to lists and successful planting of unexpected varieties.
I pile the seaweed high & never have salt issues.
Firstly, it rains a lot here, which will wash a lot of the salt out, but secondly, what we're after are the nutrients picked up from the sea by the seaweed.
 
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I pile the seaweed high & never have salt issues.
Firstly, it rains a lot here, which will wash a lot of the salt out, but secondly, what we're after are the nutrients picked up from the sea by the seaweed.
We too have that problem with rain. Wherever it rains a lot the soil lacks dissolvable nutrients. Plus with the calcium gone we get acid clay, like 5.0pH below the surface.
 

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