4

There is a list of at least 13 things that do not go into the compost pile. Most I know and understand. I just found a list that included potatoes.

Potatoes do what to a pile of compost? Feces, meats, dairy are obviously a no no but potatoes?

The only problem I can see is that a chunk of potato with an eye will grow. Is that the only reason?

stormy
  • 40,098
  • 3
  • 31
  • 75
  • 1
    lol @stormy, think of no till potatoes – black thumb Sep 04 '18 at 01:24
  • 1
    When I think potatoes I think of pushing my fingers and hands into the soil to locate tubers. There is no way one can enjoy harvesting potatoes without also 'tilling' that soil! No Till...?? – stormy Sep 04 '18 at 07:03
  • Once I've grown potatoes in the soil of my greenhouse garden, I will not be growing any of that family/genus again in that soil for two years. I've run out of room and next year I get to finally grow potatoes in pots, doing that tower thing that I go on about. I've seen this done yet have not grown potatoes this way myself. I'll probably continue to grow potatoes, tomatoes, egg plant...peppers in potting soil in pots. Trying to remember these details is tough even having drawn maps. I messed up this year with my cucumbers and used the same bed as last year. – stormy Sep 04 '18 at 07:10

3 Answers3

7

I take it you're not Irish!

The only reason for not composting potato peelings is that they are a potential source of the fungus that causes potato blight. Blight spores can survive only on living plant material. Potato peelings can provide this when the buds in the eyes of potato skins grow into potato plants. To ensure that the peelings don't sprout, bury them well down in the compost and ensure that you turn the heap regularly. If you do this, it is fine to compost the peelings.

and ...

In most of the United States and Canada, Phytophthora infestans requires a living host to survive between seasons. Usually it lives in infected potato tubers, which can survive in storage or the soil (to become volunteers) after harvest or anywhere potatoes might be discarded. Tubers that have been discarded at any stage of crop production or handling (harvest, storage, shipping, spring cleanup, or planting) are known as "culls." Culls may survive if they are not destroyed (frozen, crushed, composted, or buried at least 2 feet beneath the soil surface). Infected tubers that are planted or cull tubers that survive the winter may be sources of the pathogen that initiate epidemics the following season.

https://www.gardenorganic.org.uk/faqs/potato-peelings http://vegetablemdonline.ppath.cornell.edu/factsheets/Potato_LateBlt.htm

Graham Chiu
  • 23,044
  • 5
  • 36
  • 92
  • I am impressed hugely, Graham. This was the definitive answer. I get it. I thought they were picking on potatoes when other plants get similar blights, but this taught me something that makes perfect sense. This is also why I always pay the bucks for certified seed potatoes. I am hoping these potato towers work next year. We are also in the process building a potato cellar, really no other way to preserve them, garlic, onions, carrots? Thank you! – stormy Sep 04 '18 at 07:50
  • I am half Scot. The Lauderdale Clan? – stormy Sep 04 '18 at 07:51
  • "really no other way to preserve them" - it depends on your climate, but in the UK the traditional method for storing *farm-grown* potatoes was simply to make a heap of them (typically a "ridge" about 5 feet high by as long as necessary), cover with straw to keep them clean, then cover with a layer of earth to keep the frost out. See https://www.mediastorehouse.com/mary-evans-prints-online/potato-clamp-589476.html. It works just as well at a garden-sized scale. No need for temperature controlled buildings, nitrogen-enriched atmosphere, etc, etc!! – alephzero Sep 04 '18 at 17:31
3

They can start growing again in the compost. That in itself isn't a big deal, since you an always pull up the plants, shred them, and recompost them.

The more serious issue is that you may be infecting the compost with assorted fungus and virus diseases, Potato blight is the most obvious risk but potatoes can also carry viruses that affect related species, e.g. tomatoes. Viruses will never be killed by composting - if you want to recycle the organic waste, burn it and use the ash. If you get potato blight fungus in your soil, it will take years to eradicate it.

Note, the diseases are carried in the leaves and stems, not just in the edible bits of the plant! Composting kitchen waste containing cooked potatoes is unlikely to be a problem.

alephzero
  • 11,339
  • 1
  • 14
  • 22
  • By this logic one would assume the list of no-no's to add to compost be a lot longer. Ash is one of the no-no's to add to compost piles! Healthy plants are able to protect themselves from disease and insects. Rare to have healthy plants succumb to disease or insects. They do but still rare. I had two thick gorgeous 25 foot rows of tomatoes. Virgin soil. Late blight blew in on the wind. 3 days flat to total kill no fruit was spared. Systemic, through and through. Could've been on the asparagus starts? transported from the nursery or friend's garden soil? No problem ever since. – stormy Sep 04 '18 at 07:23
  • You and Graham had literally the same answer. I gave him the points because I shouldn't be allowed to make decisions at this hour! – stormy Sep 04 '18 at 07:58
  • 2
    Blight is a fungus not a virus – Graham Chiu Sep 04 '18 at 10:05
  • @GrahamChiu Oops, so it is. Answer edited! – alephzero Sep 04 '18 at 17:35
  • @Stormy " Healthy plants are able to protect themselves from disease" ... read up on the history of the Irish potato famine! – alephzero Sep 04 '18 at 17:37
  • 1
    I have to read up on the Irish potato famine. I have a feeling they did not practice any sort of rotation in those days and that is what caused this famine, this rampant disease of a very important mono crop. Even healthy plants if planted year after year in the same soil as its genus had been planted and grown every year, will succumb to disease. It is a wonder the potatoes lasted as long as they had...I gotta go check this out, thanks, alephzero! – stormy Sep 05 '18 at 06:51
0

I think it all depends on the temperature that the compost reaches. Cold will not kill a potato since they are exothermic; they store heat in their mass which helps them resist cold. Heat from a compost heap will dramatically weaken them - a good compost pile will reach 70 deg C pretty easily, weakening the tubers in the pile and making them vulnerable along with many fungi. And since at the time we are composting new potato haulms and recycling our old stored sprouty spuds there is plenty of fresh material going to the compost it's an ideal time to dispose of them. Right now my compost is running extremely hot with grass clippings, squash vines, spuds, ragweed, pigweed, ... A week ago it was six feet high, now down to three feet. A year from now when I use it there will be no sign of spuds at all.

From the point of view of an institution providing general advice, I guess they have to take into account all types of households: some will take composting seriously, keep a hot pile and will ignore the advice, others will end up with a slimy mess, a source of infection for other serious gardeners and the agriculture industry. It's probably best for general advice to err on the side of caution.

Colin Beckingham
  • 19,612
  • 1
  • 12
  • 43
  • I once lived fairly near the ocean and had property on a tidal river. I had insanely wonderful soil. In the middle of the winter, lots of snow, I was able to dive into my potato beds and pull up incredible potatoes. I even had a potato cellar. Zone 5/Maritime influence. All my other vegetable gardens the soil froze and those left over spuds did as well. In the spring they are a gooey gob. A few little potatoes might not freeze and actually come up in the spring but most freeze and turn to stinky goo. Love to have soil tests to discern virus, bacterial or fungus. – stormy Sep 04 '18 at 10:08