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community weblog

Household waste could make for sweeter tomatoes

Household waste could make for sweeter tomatoes. Research has found that the flavour and aroma of tomatoes improve when compost made from food and garden organics is added to the soil.
posted by chariot pulled by cassowaries on Oct 21, 2026 at 1:31 PM

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I guess we have a similar system here in Toronto, Canada because our organic waste bins can accept a lot of things like meat, diapers, or pet waste. I'm not sure who ends up buying the compost but I think any sales are a bonus from these materials being diverted from the dump because our dump space keeps filling up and it is hard to get new dumps made.
posted by any portmanteau in a storm at 1:52 PM

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This is true as far as I've experienced. For decades my grandpa would bury road-kill behind his barn near Geneva N.Y. The back of the barn faced south, and when I was about five or so, he set up a trellis and my grandma planted some kind of beefsteak tomato back there. Over the years those tomatoes were the biggest and sweetest I've ever eaten. In my 55 years on this Earth, I've never tasted their equal.
posted by Dhertiiboi at 2:17 PM

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I think any sales are a bonus from these materials being diverted from the dump because our dump space keeps filling up and it is hard to get new dumps made

I don't know if it's the same in Canada, but in Australia one of the big drivers of composting waste is not landfill space but reducing methane emissions -

if fruit, meat, lawn clippings, dog poo etc decompose in landfill, they release a lot of methane, which is a much more powerful greenhouse gas than carbon dioxide [for climate change, methane is between 28 and 80 times as powerful as CO2].

Forced-aeration compost (electrically powered air blowing through tubes through the compost) massively reduces the methane emissions.

So the main reason to do this kind of compost is to help reduce climate change.
posted by chariot pulled by cassowaries at 2:20 PM

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Better tomatos is a good enough reason for me. I like tomato sandwiches.
posted by NishanStepak at 2:33 PM

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Well, hell, this kind of sounds like a "no shit" kind of thing.

Because - where do you think nutrient-rich soil COMES from? It comes from microbes and worms breaking down organic matter and the nutrients in that matter leaching back into the dirt - so that new plants can be fed by it again. That's what compost is.
posted by EmpressCallipygos at 2:43 PM

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I'm sure environmental concerns are there but we only pay lip service to reducing climate change here in Canada. We used to send our garbage to Michigan in the USA and then stopped* when we opened our current dump but that only has about a decade until its full. The more we can divert from getting to the dump throught things like separate organic waste processing the longer that dump can remain open.

* The City of Toronto stopped sending its publicly collected waste there but apparently private companies still truck waste to the USA to be dumped because it is cheaper than dealing with it here.
posted by any portmanteau in a storm at 2:47 PM

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I guess we have a similar system here in Toronto, Canada because our organic waste bins can accept a lot of things like meat, diapers, or pet waste

Not necessarily, ours go to an anaerobic digester to break down for biomethane which then gets immediately combusted for electricity generation. Not sure what they do with the residues, which are substantial.
posted by biffa at 3:15 PM

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My compost has a large dose of foodwaste, since all my kitchen scraps go on the heap. And my tomatoes are delicious.

Can't help noticing the pathetic, underripe, pale appearance of the tomatoes in the top photo. And then the comment from the grower that they're more interested in yield than taste. I expect that because buyers can't tell if a tomato will taste great from appearance, supermarkets will not charge a premium, and no economic incentive reaches the grower. I see attempts to deal with this: there are little tomatoes sold in branded plastic boxes that promise (and deliver) a sweeter, better taste. But for anything that's just sold as "tomatoes", unbranded, and visually indistinguishable, they'll be as tasteless as possible before people stop buying them.
posted by i_am_joe's_spleen at 4:54 PM

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Well, hell, this kind of sounds like a "no shit" kind of thing.

Compost intended to be used directly on plants that people are going to eat, should always be a "no shit" kind of thing, just sayin'. :)
posted by notoriety public at 6:09 PM

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"Can't help noticing the pathetic, underripe, pale appearance of the tomatoes in the top photo. "

Years ago, I worked at a produce wholesaler for a summer. The warehouse had a tomato sorter -- they went down a conveyor and were sorted by color into bins. Most were very green, far from ripe. Those went into a room with added ethylene gas to force fast ripening, and came out red. Picking them green can't help the taste either. I suppose rock hard green tomatoes survive their long distance travel.
posted by jjj606 at 7:31 PM

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Right in the middle of my garden bed sits a discarded SUV tyre (one of the big chonky off-road ones) with a discarded satellite TV dish on top for a lid and a brick to hold that down against wind and critters. The dish nicely covers the whole tyre and the bolt holes where its mounting hardware used to be drain the water that falls on it.

I collect our food scraps, used tea bags and tea leaves, coffee grounds, and the paper towels I oil my cast iron cookware with in an upright two litre ice cream tub on the kitchen bench. That tub is lined with the bag a loaf of bread came in, which starts out partly rolled condom-style to match the height of the tub; I unroll it to keep the scraps contained as their level rises above the tub walls. There's a folded sheet of paper towel with one end under the bag and the other poking out just above the tub wall to trap and wick away any leakage from minor damage to the bag.

This arrangement comfortably holds about five litres of food scraps once the bag reaches full unroll. Our household generates that amount every week or two, which is less time than it takes for the collection to start emitting bad smells or attracting vinegar flies. The stuff in the bottom does get mouldy and gross but by the time it has there's more than enough new scrap piled on top to keep any stink well contained.

When the bag is full I twist the top closed and pull it out of the tub, then take it out to the garden and dump the contents into the tyre. Turning the bag partway inside out as I empty it avoids needing to touch any ick. I take the emptied bag inside again, rinse it out, roll the sides back down and put it back in the tub. If rinsing reveals that it's now got a hole in it, I replace it with a fresh bread bag from our big bag of plastic bags. If the paper towel in the tub shows signs of having had to absorb anything distressingly organic I put it inside the bag and replace it with a fresh one.

Those scraps are the only thing I put in that tyre. I make no attempt to maintain anything like an optimal carbon:nitrogen ratio for composting but even so, it took about six months of doing this for the tyre to get half full. Once it had, I got some compost worms from a friend, scraped back the middle of the rot pile with a trowel, dumped them in and pushed rotting scrap back over them. They've bred up beautifully now and the tyre never gets more than about a quarter full.

The design intent was for compost worms to breed up to match the rate at which our house can supply them with food scraps, and for the open bottom to induce earthworms to create an underground distribution network that spreads the resulting enrichment through the whole garden bed. And it's worked. Our landfill bin never stinks because all our food waste gets diverted from it, emptying and cleaning the scraps container is quick and easy enough that even somebody as lazy as me has no cause to resent it, and that bed is bountiful.
posted by flabdablet at 11:55 PM

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.....Huh.

Flabdablet, you've given me an idea - we have three compost bins in the community garden that used to be tended by one of our longtime members, and fed by neighbors' compost scraps. But that member has been a lot less active in the garden lately, and then the city started getting more active with its own municipal composting program - and so now the compost bins have just been sitting there, and have started attracting rats because nothing else is happening. But they're all 3/4 full so taking them apart would be a huge pain in the ass.

But you've got me wondering if we shouldn't at least try dumping a lot of worms in there first.
posted by EmpressCallipygos at 5:24 AM

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Don't bother collecting earthworms, get proper compost worms (generally sold as a three-species community of reds, blues and tigers). Little buggers are voracious. If earthworms were interested in food as rich as your compost they'd already have chewed it up by now.

If the compost in the bins is sitting directly on earth, I expect you'll find it subsiding pretty steadily and that you'll also see noticeable soil fertility, scent and structure improvement spreading out from them over time as the earthworms pick up where the compost worms leave off.
posted by flabdablet at 5:41 AM

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Also: a rat is going to have much more trouble chewing its way through a steel belted truck tyre than a typical flimsy polythene compost bin. In my experience, they also interpret a tyre sunk three inches into the ground as an insuperable barrier and don't bother trying to tunnel underneath to get inside. Doesn't have to be rat proof, just less rat easy than anything else nearby.

I think of my worm tyre as a mouth for my garden soil. Mmm, rotting kitchen scraps, num num num.
posted by flabdablet at 6:19 AM

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I have three compost piles, one I'm taking from, one I'm feeding, and one just cooking. They get switched once a year, so I don't have to turn them except for removing the outer un-rotted layer from the oldest pile. They get grass clippings, leaves, and kitchen waste I collect in a covered bucket, plus a little active compost for starter.

My garden isn't good for tomatoes, since I have black walnut trees (I grow beans, peppers, and cucumbers), but I get tons of super delicious tomatoes from plants in tree-sized pots full of compost.
posted by Miss Cellania at 6:56 AM

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Our bins are DIY and built out of wood and chicken wire. They've just been subjected to some benign neglect for a couple years, since the couple who were our "Compost Czars" are just too busy for the upkeep. I'm more thinking the worms could eat things down to a point where disassembling them would be easier, since we're all kind of thinking that getting rid of them is best but the cleanout of what's currently in there is going to be such a mammoth task that we've been procrastinating.

....The sunnier plots in the garden always get a lot of people planting tomatoes - but a lot of that is because "hey, I know, tomatoes" is a common thought for people with community garden plots. I went that route myself when I first started out, because I was thinking more like "what do I eat a lot" before thinking about "what can this plot sustain". Turns out that the light in my own plot isn't that great for tomatoes - but I've had good luck with beans, peas, and cucumbers in recent years.

....that one tomato I got one year was really good, though.
posted by EmpressCallipygos at 7:04 AM

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My compost bin is a wire one, which attracts rats which I don't mind in my yard but they have started coming on my patio. Your solution sounds way better.
posted by The_Vegetables at 8:44 AM

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notoriety public: "Well, hell, this kind of sounds like a "no shit" kind of thing.

Compost intended to be used directly on plants that people are going to eat, should always be a "no shit" kind of thing, just sayin'. :)"

Come to London, where we have lovely river sewage vegetables!
posted by goo at 8:57 AM

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DIY and built out of wood and chicken wire

Might get quite disappointing results from compost worms then, unfortunately. Ventilated walls make for a rot pile that easily and often dries out too much for them to work it, so the only place much activity ever happens is right in the middle of the very bottom of the pile.

That might not matter much if the piles are big enough. What sort of volume are we talking per bin?

I've experimented with a lot of outdoor worm farm designs over the years and if the aims are to then a big fat car tyre sat flat on the earth or sunk a couple inches into it is pretty much optimal. All it needs is a reasonably secure lid and it's good to go.

The first big win over the traditional waist-high Gedye bin is that the size of those demands so stridently to be overfilled, which means they often are, after which the rot goes anaerobic and slows down and smells bad. Anaerobic rot is also acidic enough to restrict worms to working just its edges or kill them if they can't get out from under it.

The tyre's higher surface area to volume ratio keeps the interior aerated enough that it just won't sustain anaerobic rot. I've yet to make mine do it for more than a couple of days after dumping some very wet and sloppy bags of scraps in there.

The tyre's wide patch of contact with the earth releases much less rot aroma at ground level than the narrow lip around the bottom of a Gedye bin, so it's less attractive to rodents as well as being harder to tunnel into. And the whole thing being generally closer to the ground stabilizes the internal temperature better as well.

I was super pleased when it occurred to me that this old satellite TV dish I'd taken off the roof years ago would make such a good lid for a worm tyre. Those four existing bolt holes both ventilate and water the interior to what seems miraculously close to just the right amount and I very rarely end up adding extra water by hand.

Like a bought one, except mine works.
posted by flabdablet at 10:21 AM

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In pre-conquest Tenochtitlán, then one of the world's top 3 largest cities, chinampa market gardens definitely grew tomatoes and peppers in shit. All known historical accounts agree that these veggies tasted fantastic.
posted by Headfullofair at 12:51 PM

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What sort of volume are we talking per bin?

It's a three-bin system like this, and I'd guess they're about four feet on each end instead of 3 feet. With only the chicken wire for the walls and wood for the framing (the top is solid though).
posted by EmpressCallipygos at 3:30 PM

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If a setup like that has been neglected for a while, and the edible bits inside are attracting rats instead of breaking down, by far the most likely causes are drying out and lack of turning. I wouldn't expect compost worms to help much with that. Dry environments are not really their thing.

In your shoes I'd probably try to use the contents of those bins as mulch rather than compost, so spread it over rather than dig it in. Each full bin would be 64 cubic feet, which is enough to cover 256 square feet to a depth of three inches, so they'd probably last you a while.

You could get a worm tyre mouth going to make a place to put anything you find in there that still looks food-like enough to be a rat attractant.

This plan would not work if the bins currently contain weeds whose seed they never cooked enough to kill. If that's what you're looking at then working with the bins to re-moisten and turn them might be your best bet. If you can get a good hot rot going again and turn and re-moisten it every few days for a month or so, you'll probably end up with enough nice compost to fill just one of your bins.

You might even surprise yourself and come to enjoy the process as much as your former czars did. Shovel work sounds like a pain in the arse but there's something absurdly satisfying about stirring and drawing out the chimney stake from a properly working compost heap to release a rising column of sweet-smelling steam.
posted by flabdablet at 12:38 AM

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