Urine as a Fertilizer

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Gardening, Vegetable Gardening
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How do I spend my Saturday mornings you ask? Answer: scanning the peer reviewed literature for articles about using human urine as a nitrogen source in the garden, i.e. taking a leak in the watering can. As we’re currently hosting some excellent classes at our house taught by Darren Butler, a big proponent of what he calls “pee-pee-ponics,” I thought I’d take a look at the science of urine use.

Urine offers a free and readily available (at least after a night of beer drinking) alternative to organic nitrogen fertilizers such as blood meal. We’ve got a perpetual nitrogen deficiency in our vegetable beds and I hate buying industrial ag sourced items like blood meal. Urine is a great alternative.

To use urine in the garden you’ve got to dilute it with water, at least ten to one. Straight urine will burn your plants. Thankfully we don’t worry about our sauerkraut taking on a urine flavor:

Use of Human Urine Fertilizer in Cultivation of Cabbage (Brassica oleracea)––Impacts on Chemical, Microbial, and Flavor Quality by Surendra K. Pradhan, Anne-Marja Nerg, Annalena Sjöblom, Jarmo K. Holopainen and Helvi Heinonen-Tanski

Human urine was used as a fertilizer in cabbage cultivation and compared with industrial fertilizer and nonfertilizer treatments. Urine achieved equal fertilizer value to industrial fertilizer when both were used at a dose of 180 kg N/ha. Growth, biomass, and levels of chloride were slightly higher in urine-fertilized cabbage than with industrial-fertilized cabbage but clearly differed from nonfertilized. Insect damage was lower in urine-fertilized than in industrial-fertilized plots but more extensive than in nonfertilized plots. Microbiological quality of urine-fertilized cabbage and sauerkraut made from the cabbage was similar to that in the other fertilized cabbages. Furthermore, the level of glucosinolates and the taste of sauerkrauts were similar in cabbages from all three fertilization treatments. Our results show that human urine could be used as a fertilizer for cabbage and does not pose any significant hygienic threats or leave any distinctive flavor in food products.

As the study above noted, too much nitrogen (from any source) can cause pest outbreaks. And we do need to be judicious in our urine application in alkaline soils such as here in Los Angeles as urine has a high pH:

From Human urine – Chemical composition and fertilizer use efficiency by H. Kirchmann and S. Pettersson:

Stored human urine had pH values of 8.9 and was composed of eight main ionic species (> 0.1 meq L–1), the cations Na, K, NH4, Ca and the anions, Cl, SO4, PO4 and HCO3. Nitrogen was mainly (> 90%) present as ammoniacal N, with ammonium bicarbonate being the dominant compound. Urea and urate decomposed during storage. Heavy metal concentrations in urine samples were low compared with other organic fertilizers, but copper, mercury, nickel and zinc were 10–500 times higher in urine than in precipitation and surface waters. In a pot experiment with15N labelled human urine, higher gaseous losses and lower crop uptake (barley) of urine N than of labelled ammonium nitrate were found. Phosphorus present in urine was utilized at a higher rate than soluble phosphate, showing that urine P is at least as available to crops as soluble P fertilizers.

With some common sense urine application (i.e. not too much), it clearly makes a good fertilizer:

Stored Human Urine Supplemented with Wood Ash as Fertilizer in Tomato (Solanum lycopersicum) Cultivation and Its Impacts on Fruit Yield and Quality by Surendra K. Pradhan, Jarmo K. Holopainen and Helvi Heinonen-Tanski:

This study evaluates the use of human urine and wood ash as fertilizers for tomato cultivation in a greenhouse. Tomatoes were cultivated in pots and treated with 135 kg of N/ha applied as mineral fertilizer, urine + ash, urine only, and control (no fertilization). The urine fertilized plants produced equal amounts of tomato fruits as mineral fertilized plants and 4.2 times more fruits than nonfertilized plants. The levels of lycopene were similar in tomato fruits from all fertilization treatments, but the amount of soluble sugars was lower and Cl− was higher in urine + ash fertilized tomato fruits. The β-carotene content was greater and the NO3− content was lower in urine fertilized tomato fruits. No enteric indicator microorganisms were detected in any tomato fruits. The results suggest that urine with/without wood ash can be used as a substitute for mineral fertilizer to increase the yields of tomato without posing any microbial or chemical risks.

So go forth and pee (and dilute!). You can also, of course, just pee on the compost pile.

Many thanks to the always useful Google Scholar, one of my favorite gardening resources.

Derek Jarman’s Garden

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Garden Design, Gardening
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Photo by angusf

Avant-garde filmmaker Derek Jarman spent the last years of his life, after an HIV diagnosis, tending a bleak, wind-swept patch of land opposite a nuclear power plant on the southern coast of England. With just a few hardy plants and some scavenged pieces of wood he put together a stunning garden. He wrote a book about it called, simply, Derek Jarman’s Garden. You can also view a flikr photo set here.

Photo by angusf

Jarman’s friend Howard Sooley, writing in the Guardian, described the garden and cottage:

Prospect Cottage sits more or less in the middle, parched by baking sun and drying winds in summer, with no shade to be had for miles in any direction. In winter, sea storms rage, while biting Siberian winds push through the shingle and up through the floorboards of the fisherman’s cottages strung out along the road to the lighthouse.

You can’t take life for granted in Dungeness: every bloom that flowers through the shingle is a miracle, a triumph of nature. Derek knew this more than anyone.

Gardens give us food, medicine, solace, and the best of them, like Jarman’s, remind us of the impermanence of our lives and the inevitability of change.

Scott’s Pepsi-G Stove

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Design, Preparedness
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If you’ve ever backpacked any distance you’ll appreciate the need to reduce weight, taken to its logical extreme by the sort of folks who cut their toothbrushes in half. This ultra-light subculture, to our benefit, seems to be populated by engineering types who like to create useful lists and detailed instructions. And, even if you don’t backpack, these innovative ideas can be used in your emergency preparedness plans.

One of my favorite ultra-light backpacking gadgets is the Pepsi can stove, which has reappeared on the interwebs, after a prolonged absence, here.

To make a Pepsi stove you take the bottom of a 12 oz Pepsi can and the bottom of a Guinness Draught can and, after a series of precise cuts and pin pricks you end up with a nifty cooking stove that uses denatured alcohol or methanol (both easily obtained at any hardware store) as fuel.

Efficiency-wise, if you consider the ratio of weight to heat output, you’re better off with a commercial backpacking stove and fuel canisters. But such stoves are expensive and the fuel canisters are only available at camping and sporting goods stores. The nice thing about the Pepsi can stove is that it’s almost free to make and you can find the fuel at any hardware store. I keep both a Pepsi can stove and a MSR backpacking stove in my backpack. That way I’ve got a backup in case one fails to work.

Mrs. Homegrown here:

I thought I’d toss in a little more detail for those of you unfamiliar with the concept. A Pepsi can stove is tiny and very light weight, good for two things–ultralight backpacking and as a simple cooking device for what some people call a bug out bag–emergency gear that is ready to grab and go.

I’ve taken one with me backpacking, as my only stove. It works fine, but it is limited in its capabilities. It can boil a cup or so of water at a time, enough to make one person a hot drink, or enough water to rehydrate a pouch of something. You certainly can’t make pancakes over one, and if you have a family to serve, you might want to consider carrying more than one of these stoves.

My camping set up included the stove, a sawed off Foster’s can (you know, those extra large beer cans) as a cooking pot, a circle of chicken wire to balance the Foster’s can upon over the stove, and a bit of foil to block wind. It all tucked inside the Foster’s can for transport and weighted hardly anything. Oh, and I kept the fuel in one of those plastic collapsible water bottles.

As Erik says, a lightweight camping stove and proper fuel canister is a much more flexible and powerful option, but little Pepsi can stoves can’t be beat for price or weight.

Here’s our 2006 post on the same subject–along with a nice photo of ours burning.

Emergency Supplies: It’s all about the lids

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Domesticus, Preparedness
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Above you see one five gallon bucket transformed into a toilet, and another into a food storage container, by virtue of specialty lids.

The toilet seat lid I have here is called Luggable Loo Seat Cover and, miraculously, it is made in Canada. I bought it at REI.

The other lid is called a Gamma Seal, and it is USA made. Do I see a trend, here? Anyway, this I found at an Army surplus store. The Gamma Seal is a two part lid that fits most 3-7 gallon buckets. One part of the lid is an adapter ring that snaps on the rim bucket. (“Snaps” is a euphemism for “Fits on after straining, swearing, hammering and finally calling for the husband.” In the end, Erik held it down while I beat it–er–I mean, snapped it into place.)  The lid itself spins and seals with a gasket. This gives it a nice, bug and moisture proof seal for all sorts of storage needs, transforming your ordinary buckets into superbuckets.

The set up above is actually a birthday gift for a friend who’s expressed interest in being better prepared for emergencies. Especially as regards what we like to call “Toilet Freedom.” Okay, so a toilet doesn’t scream birthday–but you know, she’s used to us and our ways.

We’re giving her the black bucket and matching loo seat with a plastic bag full of wood shavings inside and a tp roll, so it’s ready to rock as a composting toilet. (For more on composting toilets, see this post of ours  or go straight to the source, The Humanure Handbook.)

The green bucket holds enough preservative-filled, ready-to-eat food to hold her for a day or two without access to cooking water or a stove. I deliberately chose foods that she wouldn’t be tempted to eat prior to the natural disaster/zombie attack. Not gross things–you don’t want to be challenging your stomach in an emergency–but kind of boring things, such as plain crunchy granola bars, as opposed to the tempting, chewy, chocolate-dipped variety. There’s also some raisins in there, pop-top tuna cans, applesauce cups and peanut butter crackers.

There’s plenty of room for her to add more, depending on what she wants to be prepared for. And there are so many types of emergencies to choose from! I mean really, where do we start? She might want to add some dehydrated stuff and drink mixes for situations in which she has plenty of water and a fire source. It’s nice to have hot food, even if it is packed with sodium. Or for longer emergencies, she might want to consider storing fast cooking dry goods, like white rice and lentils, and high calorie foods, like oil, peanut butter and honey.

Sealed buckets like this are also a good place to store other things you’ll need in an emergency, including medications, first aid kits, extra glasses and copies of important documents.

A few snacks in a five gallon bucket won’t feed a person forever, but it’s a start. It can make the difference between misery and comfort for the first day or two after a disaster. In disaster preparedness, don’t let the perfect get in the way of the good. Do what you can. Everything helps.

With these two buckets we’ve got food and sanitation covered. The third big category–and perhaps the most vital of all– is stored water, which our friend already has under control. For tips on water storage, see our recent post on water storage.

So-So Tomatoes Become Excellent When Dried

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Domesticus, Food, Solar
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As we reported earlier, we weren’t thrilled with our cherry tomato choice this summer. They were just plain dull. They were also rather large for a cherry, more like mini-plum tomatoes, which made them awkward for salads. But they were healthy plants, and very, very prolific. In situations like this it is good to remember that tomatoes which don’t taste good off the bush often cook or dry well. The ratio of skin and seeds to pulp in these tomatoes made them a bad candidate for sauce, so we’ve been drying them.

And man, are they good dried. Like tomato candy. It’s very hard not to snack on them, but I’m trying to save them for the depths of winter, when I really miss tomatoes.

We have maybe a couple of quarts of them now. Several years ago we had an absolute disaster involving a pantry moth, its many offspring, and one big jar of dried tomatoes. For this reason I’m storing the dried tomatoes in a series of small jars, to offset the risk. Another good tip for fending off moths is to freeze any food stuff which you suspect might be at risk for 4 days to kill moths and their larvae.

How did we dry our tomatoes, you ask? Usually we use our homemade solar dehydrator, but this year we’ve got a friend’s electric dehydrator on loan. It seemed wicked to run the thing day and night, but it dries a lot faster, and with less work overall, than our solar set-up. (Oh, the wonders of Modern Living!) The one thing I did not like, though, was the constant noise. The dehydrator sounds a little like a running microwave, not loud, but persistent. I was always half-consciously expecting to hear the microwave “ding!” at any moment.

So, while the electric dehydrator let us process this crop of tomatoes in record time, I don’t think we’re going to ever buy one ourselves. Old Betsy, the wonky wooden dehydrator, suits us well enough.