One of my advice questions was answered without references given, and I can only assume it's anecdotal. Is it expecting too much on this site to ask/expect people to provide references to back up their answers?

To answer my own question to some extent, I think that the answers containing reliable references (articles at university horticultural extensions/research studies, etc.) will indicate higher answer quality and will help improve the quality of the site.

That's not to say that people should be discouraged from answering from anecdotal experience, because sometimes it may be the only information available.


To begin, a related question exists to evaluate claims' authority, any input here would very likely inform any decisions over there.

As to 'should answers need sources?', the answer is a mixed one. Gardening is a blend of prior knowledge mixed with the experience gained through improvising. In some cases, the personal experimentation is what will give the edge to a great answer. In other cases, it can result in unfortunate consequences. Here I would draw an analogy with cooking a fantastic tasting meal, but inadvertantly downing everyone at the table with food poisoning.

There are three ways to break this up:

  • Questions requiring expertise and experience, but that are unlikely to carry unintended consequences
  • Questions requiring expertise and experience, but whose unforeseen/unlikely unintended consequences are not incredibly substantial
  • Questions requiring expertise and experience, and are likely to carry unintended, serious consequences

In the first case, I would cite my response to how to keep critters away; put up a statue of an owl. This has worked for me, maybe it won't for you or the pests you're dealing with, but at the end of the day no plants or persons will be any more or less harmed as a result of following the advice. Anecdotal answers are fine, backing them up is a plus.

In the second case, I would cite my response to how to keep critters off your irrigation; spray hot pepper oil on the equipment. In most cases I cannot see how this would carry consequences, but perhaps the oil eats through some cheap plastic tubing. No plants or people are really that harmed, no expensive equipment was really damaged. Anecdotal answers work, but some fact-checking and thinking about the possible unintended consequences (and probably voicing them in the answer) is a bit requisite for a thorough answer.

In the last case where the consequences might be severe, I would cite the question about making compost tea while avoiding e. coli. While I am glad it has one source. As a question-asker, I personally would not trust that source or consider the answer to be authoritative (particularly, because it cites only one source to assuage the concerns of someone worried about food poisoning). It has nothing to do with their credentials, it is because these questions voice a concern about bacteria and other pathogens. Similarly, while losing a random basil sprout isn't a big deal, losing an incredibly rare flower or heirloom variety of tomato (perhaps imported by your great grandfather from Italy) would certainly change the weight of any given answer. [Here I would refer to the list offered through Aaronut] on Cooking.se3.

  • While I don't believe it is necessary to make every answer conform to the authority criteria, I think it is typically in everyone's best interest to first evaluate the type of question (and the possible consequences of implementing a given answer).
  • If the question falls into that third category, and I asked it, I am unlikely to accept any answer that doesn't at least try to show it's work.
  • If you have been making compost tea the same way for 30 years and have never contracted a food-bourne illness, that's fantastic; but please be very thorough in explaining what you do, and reference other guides to really explain it so that I don't try to follow your method and screw up.

The only problem is trying to diagnose where exactly the question falls. I think another question should be asked to address the scope of the site in this regard. For instance, although food safety guidelines are an important aspect of Cooking.se, asking about nutrition is considered out of scope. I am not sure this exact concept comports, but a similar consideration might be fruitful.


Well, while there might be references online, most people who are knowledgable in this area might not even be aware of them. For them, their knowledge mostly comes from experience and hanging around folks who are more experienced. In my opinion, expecting/forcing them to provide a reference for every single claim will only turn this into skeptics.SE and make people disinterested in participating.

At some level, you rely on trust. How do you know if the random article that was linked to is actually scientific or some dude jotting down his anecdotal advice? You don't go to Shirlock Homes on DIY.SE and say "umm dude, you got a reference for using screws instead of nails?" No. You trust that people are here to give their honest advice. Sometimes that advice might be wrong, but there will always be someone who comes by and says that it is wrong and corrects them, or fills in missing info. This would not happen if there were no experts.

Moreover, you should only take the answers here as a guidance. If you want solid references, you ought to try to find them yourself based on the pointers given in the answers.

  • I didn't mean to imply that people are being dishonest, it's just that often anecdotal evidence isn't correct because human perception is often easily distorted or tricked. Of course there are varying quality levels of references, ranging from personal blog posts to large-scale controlled studies. A strong reference would add confidence to the answer. – glenviewjeff Jun 17 '11 at 14:05
  • +1 - that and the fact that there probably are no references for some of these questions. – JonH Jun 17 '11 at 14:05

+1 to what mfg said.

I would also add, if you're trying to get answers with authoritative references:

The more specific the question, the more likely you are to get references. Your question "Is it possible to indefinitely limit growth of trees, hedges, and shrubs?" could be improved to provide us with information on the species you're trying to limit.

You've asked a general question and gotten some general advice. The truly authoritative answer to your question is, "it depends". Some species tolerate pruning better than others.

If you had asked "Is it possible to indefinitely limit the height and width of my arborvitae hedge?" it would be easier to quote chapter and verse from a book that one of us has on doing exactly what you want. If you substitute a different species, the answer might simply be "No, that tree will not tolerate pruning".

Unsure of the species? Post a question with pictures, your location, and some description and someone here will probably know exactly what you've got.


I probably answered your question regarding something to the effect of limiting the growth of a plant. I think if you want a bunch of references from other sites, state so in your answer. In most cases, references are not always trust worthy though.

I actually like when people give their own personal advice based on there experience. There are a lot of people on this site (gardeninig) who know what they are talking about, so I generally trust the person answering the question.

If you don't like the personal advice, I guess you can take that and do some searching via the web / books based on the advice given. You may be able to get more / better information. But forcing references is definately not the key.

  • please don't take this personally; it's not an indictment. I am only wondering what the standards should be here. As I said in the comment to @yoda, it's not about trust, but about science and evidence. – glenviewjeff Jun 17 '11 at 14:08
  • @glenviewjeff - ohh I know I completly understand, its hard to tell my tone from my post. I am definately not taking it personally. – JonH Jun 17 '11 at 15:01
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    I completely agree. I want anecdotal advice, and I get exasperated when someone answers a question with text quoted from elsewhere. I want what's worked for someone else; if I wanted advice directly from a book, I'd go look it up myself! I often follow the advice in my RHS and other books, but gardening is all about trial and error ... what the book 'says' doesn't always work. It often takes experimentation to find the best method. – Shanna Jun 24 '11 at 5:51

Like this answer, I sometimes just answer to put my two cents in, I don't feel bad if my answers linger one or two votes, nor do I suppose that my grandpa is rolling over in his grave for his wisdom not being authoritative. What would make him roll over in his grave is if his wisdom was despised for not being authoritative.

On this lettuce question I accepted the answer that I found to be most authoritative (although the other answers were very good and I upvoted them all), and I think I'll wait on most of my other questions to accept an answer until I hear something expert sounding.

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